Tungsten alloy wire and preparation method and use thereof, tungsten carbide alloy filament

Abstract

The present invention relates to the technical field of filament cathode materials, and in particular to a tungsten alloy wire, a preparation method and use thereof, and a tungsten carbide alloy filament. The tungsten alloy filament comprises the following components: the tungsten alloy comprises the following components: 0.0005-0.3wt% carbon element, 0.25-2.6wt% M element, 0.05-0.5wt% oxygen element, the remainder being tungsten element and inevitable impurities, and the components do not contain thorium element; the initial recrystallization temperature of the tungsten alloy wire is 48%Fc-56%Fc, and / or, the average size of its 80%Fc recrystallized grains is (1-15) μm. The tungsten alloy wire does not contain thorium element and does not have radioactive pollution problem. Its initial recrystallization temperature is between 48%Fc and 56%Fc. Its processing performance is greatly improved compared with thoriated tungsten material. Compared with thoriated tungsten wire, the wire has fewer flaw detection crack points. It is used as the matrix of tungsten carbide alloy filament. After carburization, the tungsten matrix has fine grains. The filament is not easy to break during the production and use of magnetron coils (i.e., filaments), and the production yield and quality are improved.

Description

Technical Field

[0001] The invention relates to the technical field of filament cathode materials, and in particular to a tungsten alloy wire and a preparation method and application thereof, and a tungsten carbide alloy filament. Background Art

[0002] The filament cathode is the electron emitter and is widely used in the field of microwave oven magnetrons. The performance of the filament cathode has a great influence on the working characteristics and life of the magnetron and is regarded as the heart of the magnetron. Existing filament materials are mainly made of tungsten-thorium oxide materials or tungsten-rare earth oxides, for example:

[0003] The Chinese invention patent with application number CN201010299139 and publication date April 3, 2013, discloses a doping method for powder for magnetron coils. The process of the invention includes steps such as doping, stirring, and steam drying. It is characterized in that a neutralizing additive ammonia NH3·H2O solution is added to the thorium nitrate solution, and the prepared mixed solution is evenly sprayed onto the surface of the blue tungsten WO2.9 placed in the doping pot and stirred. The doping pot is evacuated and heated with water, while stirring while heating. In a vacuum state, the powder is dried by steam heating, and finally a doped tungsten-thorium oxide powder with uniform doping and low impurity content is obtained;

[0004] The invention patent (application number CN201010299139) adds thorium oxide to pure tungsten, and the service life of the magnetron coil material can reach more than 1000 hours of continuous operation. However, the cathode product made of this composite material has a high brittle-ductile transition temperature and is difficult to process and form, which can easily lead to the magnetron cathode breaking during production and transportation. In addition, the recrystallization temperature is low, and the magnetron coil will undergo abnormal recrystallization growth during the carbonization process, and often break during use and transportation, causing the magnetron to fail. At the same time, thorium is a radioactive element. Using thorium as the main added raw material will pollute the environment during smelting, production, transportation and use, and the final product made will also have potential adverse effects on the health of those who come into contact with it.

[0005] In summary, the traditional tungsten-thorium filament is radioactive, which not only pollutes the environment, but also has potential adverse effects on the health of the final product. In addition, the existing tungsten-thorium filament has a low recrystallization temperature, many cracks in the wire, and the magnetron coil will grow abnormally during the carbonization process, which often causes it to break during production, use and transportation, resulting in low product yield and poor quality. How to solve the above problems is the difficulty that technicians in this field are committed to overcoming. Summary of the invention

[0006] To solve the problems existing in the above-mentioned prior art: the traditional thorium tungsten filament is radioactive, which not only pollutes the environment, but also has potential adverse effects on the health of the contactors. In addition, the tungsten matrix of the existing thorium tungsten filament after carburization is a fully recrystallized structure with coarse grains, which will cause the filament to break easily during the production and use of the magnetron. In addition, the thorium-containing tungsten material also has the problems of poor processing performance and many wire defects. The present invention provides a tungsten alloy filament and a preparation method, and the specific technical scheme is as follows:

[0007] The present invention provides a method for preparing tungsten alloy wire, and its technical solution is:

[0008] The tungsten alloy comprises the following components: 0.005-0.3wt% carbon element, 0.25-2.6wt% M element, 0.05-0.5wt% oxygen element, and the balance is tungsten element and inevitable impurities, and the components do not contain thorium element; the M element is selected from one or more combinations of La, Y, Sc, Nd, Sm, Lu, Ce, Gd, Tb, Dy, Ho, Pr, Er, Tm, Yb, Eu, Hf, and Zr;

[0009] The preparation process of the tungsten alloy wire includes the steps of doping powder making, powder pressing, sintering, and pressure processing in sequence; in the pressure processing step, the sintered tungsten alloy billet obtained after sintering is refined to an intermediate specification wire with a diameter of 1.5 to 3.5 mm; then the intermediate specification wire is subjected to oxidation annealing at (1200 to 1500)°C, and the annealing speed is (3 to 10) m / min; after oxidation annealing, the intermediate specification wire is further processed to the required wire diameter specification, so as to obtain the tungsten alloy wire;

[0010] Wherein, the initial recrystallization temperature of the tungsten alloy wire is 48%Fc-56%Fc, and / or the average size of its 80%Fc recrystallized grains is (1-15) μm.

[0011] In one embodiment, the sintering step adopts a high-temperature sintering method to obtain a tungsten alloy sintered billet; the heating curve of the high-temperature sintering is: heating from room temperature to A1 at a certain rate, and keeping warm at A1 for a certain time; heating from A1 to A2, the heating time is H3; keeping warm at A2 for H4 hours; wherein A1 is (950-1250)°C, H3 is (1.5-2.5)h, A2 is (1300-1500)°C, and H4 is (2.5-4.5); heating from A2 to A3 at a certain rate, A3 is (1700-1900)°C; keeping warm at A3 for a certain time; heating from A3 to A4 at a certain rate, A4 is (2050-2250)°C; keeping warm at A4 for a certain time; cooling naturally from A4 to obtain.

[0012] In one embodiment, the heating curve of the high temperature sintering is: from room temperature to A1, the heating time H1 is (5-8) h, A1 is (950-1250) ° C; keep warm at A1 for H2 hours, H2 is (1-3); from A1 to A2, the heating time is H3, H3 is (1.5-2.5) h, A2 is (1300-1500) ° C; keep warm at A2 for H4 hours, H4 is (2.5- 4.5); heating from A2 to A3, heating time is H5, H5 is (1~3)h, A3 is (1700~1900)℃; keeping at A3 for H6 hours, H6 is (1~3); heating from A3 to A4, heating time is H7, H7 is (1~3)h, A4 is (2050~2250)℃; keeping at A4 for H8 hours, H8 is (5~10); cooling naturally from A4, the result is obtained.

[0013] In some embodiments, the M element exists in the form of oxide, and the average size of the oxide particles in the tungsten alloy wire is (100-500) nm.

[0014] In some embodiments, the density of the sintered tungsten alloy billet is 17.5-18.3 g / cm 3 ; The average size of the oxide particles of the sintered tungsten alloy billet is less than 2.0 μm.

[0015] The present invention provides a tungsten alloy wire, which comprises the following components: 0.0005-0.3wt% of carbon element, 0.25-2.6wt% of the M element, 0.05-0.5wt% of oxygen element, and the remainder is tungsten element and inevitable impurities, and the components do not contain thorium element; wherein the M element is selected from one or more combinations of La, Y, Sc, Nd, Sm, Lu, Ce, Gd, Tb, Dy, Ho, Pr, Er, Tm, Yb, Eu, Hf, and Zr; the initial recrystallization temperature of the tungsten alloy wire is 48%Fc-56%Fc, and / or the average size of its 80%Fc recrystallized grains is (1-15)μm.

[0016] In some embodiments, the M element exists in the form of oxide, and the average size of the oxide particles in the tungsten alloy wire is (100-500) nm.

[0017] In one embodiment, the M element exists in the form of an oxide, and the carbon element exists in the form of a carbide or a single carbon substance; the oxide of M is selected from one or more combinations of lanthanum oxide, yttrium oxide, scandium oxide, neodymium oxide, samarium oxide, lutetium oxide, cerium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, praseodymium oxide, erbium oxide, hafnium oxide, and zirconium oxide; the carbide is selected from one or more combinations of lanthanum carbide, zirconium carbide, yttrium carbide, hafnium carbide, and tungsten carbide.

[0018] In one embodiment, the wire diameter of the tungsten alloy wire is 800 μm or less, and the number of flaw detection cracks is less than 5 per 100 meters.

[0019] In one embodiment, the components of the tungsten alloy wire further include a T element; the T element is a metal element, and the T is selected from at least one of K, Re, Mo, Fe, and Co; the mass content of the Re in the tungsten alloy wire is less than 1000 ppm.

[0020] The present invention also provides a use of the tungsten alloy wire as described above. After the tungsten alloy filament is carbonized, it is used as a cathode alloy wire for a microwave heating device.

[0021] The present invention also provides a tungsten carbide alloy filament, which is obtained by carbonizing the above tungsten alloy wire.

[0022] Based on the above, compared with the prior art, the present invention has the following advantages:

[0023] The tungsten alloy wire of the present invention does not contain thorium element and does not have the radioactive pollution problem of traditional thorium tungsten filaments;

[0024] The recrystallization temperature of the tungsten alloy wire of the present invention is between 48%Fc and 56%Fc, and its processing performance is greatly improved compared with thoriated tungsten materials. Compared with thoriated tungsten materials, the wire provided by the present invention has fewer flaw detection crack points, and is applied as a matrix of tungsten carbide alloy filaments. After carburization, the tungsten matrix has fine grains, and the filament is not easy to break during the production and use of the magnetron coil (i.e., the filament), thereby improving the production qualification rate and quality.

[0025] Other features and beneficial effects of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other beneficial effects of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 A schematic diagram of a portion of the structure of the carburized tungsten alloy filament provided by the present invention;

[0028] Figure 2 A schematic structural diagram of a cross section of a carburized tungsten alloy filament provided by the present invention;

[0029] Figure 3 This is a schematic structural diagram of the longitudinal section of the carburized tungsten alloy filament provided by the present invention;

[0030] Figure 4 for Figure 2 The enlarged view of point A in the middle;

[0031] Figure 5 A partial structural schematic diagram of a cross section of a carburized tungsten alloy filament provided by the present invention;

[0032] Figure 6 The metallographic image of Comparative Example 1 provided by the present invention at 44% FC;

[0033] Figure 7 The metallographic image of Comparative Example 1 provided by the present invention at 46% FC;

[0034] Figure 8 The metallographic image of Comparative Example 1 provided by the present invention at 48% FC;

[0035] Fig. 9 The metallographic image of Comparative Example 1 provided by the present invention at 50% FC;

[0036] Fig.10 The metallographic image of Example 1 provided by the present invention at 48% FC;

[0037] Fig.11 The metallographic image of Example 1 provided by the present invention at 50% FC;

[0038] Fig.12 The metallographic image of Example 1 provided by the present invention at 52% FC;

[0039] Fig.13 A schematic diagram of the crystal structure of Comparative Example 1 provided by the present invention;

[0040] Fig.14 A schematic diagram of the crystal structure of Example 1 provided by the present invention;

[0041] Fig.15 A diagram showing the channel distribution of the cross section of Example 1 provided by the present invention;

[0042] Fig.16 A diagram showing the channel distribution in the longitudinal section of Example 1 provided by the present invention;

[0043] Fig.17 A diagram showing the channel distribution of the cross section of Comparative Example 1 provided by the present invention;

[0044] Fig.18 A schematic diagram of the process flow of preparing a heating device from tungsten alloy wire provided by the present invention;

[0045] Fig.19 This is the conversion relationship diagram between FC% and degrees Celsius;

[0046] Fig. 20 Schematic diagram of the high temperature sintering process.

[0047] Reference numerals:

[0048] 100 substrate 200 carbonized layer 210 channel

[0049] 220 outer edge of the filament 211 first channel 212 second channel DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and cannot be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have the same meanings as these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined in the present invention.

[0052] The present invention provides a tungsten alloy wire, and its technical solution is as follows:

[0053] The tungsten alloy comprises the following components: 0.0005-0.3wt% carbon element, 0.25-2.6wt% M element, 0.05-0.5wt% oxygen element, and the remainder is tungsten element and inevitable impurities, and its components do not contain thorium element; wherein, the M element is selected from one or more combinations of La, Y, Sc, Nd, Sm, Lu, Ce, Gd, Tb, Dy, Ho, Pr, Er, Tm, Yb, Eu, Hf, and Zr; the M element exists in the form of oxide, and the carbon element exists in the form of carbide or carbon element.

[0054] The initial recrystallization temperature of the tungsten alloy wire is 48%Fc-56%Fc, and / or the average size of the 80%Fc recrystallized grains is (1-15) μm.

[0055] For component composition:

[0056] The present invention adds one or more oxides of M and carbon elements. Since the oxides of M and carbides in the tungsten matrix react at high temperatures (the working temperature of the tungsten carbide alloy filament is a high temperature condition), for example, lanthanum oxide reacts with tungsten carbide to generate lanthanum atoms, and the size of the generated lanthanum atoms is much smaller than that of lanthanum oxide particles. In this way, the migration and diffusion speed of lanthanum atoms in the tungsten matrix will be very fast, thereby improving the diffusion speed of M metal atoms.

[0057] In summary, compared with thoriated tungsten filaments, the present invention uses M oxide combined with carbon element (carbide or carbon element), which can achieve the same or even higher electron emission capability as thoriated tungsten at a lower operating voltage (excitation temperature), and it is easier to ensure the balance between the loss and migration of rare earth atoms in the carbide layer of the filament, thereby ensuring the stability of the filament electron emission.

[0058] For the starting recrystallization temperature characteristics:

[0059] The initial recrystallization temperature of the tungsten alloy wire provided by the present invention is higher than that of the thoriated tungsten wire, which is 48%Fc to 56%Fc in the present application, while the thoriated tungsten wire is about 46%FC (2020°C).

[0060] The average size of 80%Fc recrystallized grains of the tungsten alloy wire provided by the present invention is finer than that of thoriated tungsten wire. The average size of 80%Fc recrystallized grains of the tungsten alloy wire of the present application is (1-15) μm, and the average size of 80%Fc recrystallized grains of thoriated tungsten filament is (16-150) μm.

[0061] The above characteristics of high initial recrystallization temperature and small average size of 80% Fc recrystallized grains make the tungsten matrix structure of the filament produced by the tungsten alloy wire of the present invention finer than that of the thorium tungsten filament after carburization in the magnetron;

[0062] There is a carbonization process in the preparation of tungsten alloy wire into carbonized layer filament. The carbonization temperature is 2000-2500℃. The original thoriated tungsten filament is carbonized at this temperature (analysis shows that the reason is that its initial recrystallization temperature is too low), and the grain structure will show recrystallization phenomenon. The grains are coarse, resulting in the filament being brittle and having poor seismic resistance after carbonization. It is very easy to break the wire during the assembly, production, transportation and subsequent use of the microwave oven.

[0063] Compared with the thoriated tungsten filament, the initial recrystallization temperature of the filament material produced by the present invention is higher than that of the original thoriated tungsten filament, and the average size of the 80% Fc recrystallized grains is smaller than that of the original thoriated tungsten filament. After the tungsten alloy wire of the present invention is carburized, the filament structure is still a fine-grained structure, and the brittleness is less than that of the traditional thoriated tungsten filament material. The tungsten alloy filament with a fine-grained structure has better anti-seismic performance than the thoriated tungsten filament. The filament breakage rate of the magnetron produced by the present invention is much lower than that of the magnetron produced by the traditional thoriated tungsten.

[0064] Optionally, the initial recrystallization temperature of the tungsten alloy wire may be 48%-52% FC, such as 48% FC, 50% FC, 52% FC, and the like.

[0065] Optionally, the average size of 80%Fc recrystallized grains of the tungsten alloy wire can be (1-8) μm, (8-12)% μm, (12-15) μm, etc., for example, 4.0 μm, 8.5 μm, 13 μm, etc.

[0066] Regarding the average size characteristics of the oxide particles in the tungsten alloy wire: the average size of the oxide particles in the tungsten alloy wire is (100-500) nm.

[0067] The average size of the oxide particles of the tungsten alloy wire of the present application is (100-500) nm.

[0068] The reason why the oxide particle size of the tungsten alloy wire of the present application is controlled within the specified range of the present application is that the oxide particle size of the tungsten alloy wire determines the oxide particle size of the filament after carbonization. If the oxide particles of the wire are too coarse relative to the specified range of the present application, it will be more difficult for the oxide particles of M to migrate to the surface of the filament during the use of the magnetron, which will make it easier to break the balance between the loss and replenishment of rare earth elements on the surface of the filament, and thus the electron emission of the magnetron will be more unstable.

[0069] Optionally, the average size of the oxide particles may also be (100-300) nm, (300-500) nm, etc., for example, 200 nm, 300 nm, 450 nm, etc.

[0070] The present invention also provides a preferred embodiment of a method for preparing tungsten alloy wire to achieve the above-mentioned recrystallization temperature range and average size range parameters of oxide particles:

[0071] It includes the following steps:

[0072] Step 1, obtaining a finished powder raw material through a doping process, a reduction process and a powder making process in sequence; wherein the doping process is solid-liquid doping or solid-solid doping;

[0073] Step 2, powder pressing: using isostatic pressing to press powders of different particle sizes into green compacts, and pre-sintering the green compacts at low temperature in a hydrogen atmosphere to increase the green compact strength; wherein the powders are pressed into green compacts with a unit weight of 1.5 to 5.0 kg at a pressure of 160 to 240 MPa;

[0074] Step 3: High temperature sintering: high temperature sintering or vertical melting sintering is used to obtain a density of 17.5-18.3 g / cm 3 The sintered billet is to obtain the tungsten alloy material in billet form;

[0075] The heating curve of the high temperature sintering is:

[0076] From room temperature to A1, the heating time H1 is (5-8) h, and A1 is (950-1250) °C;

[0077] For example, H1 is (5-7) h, (7-8) h, etc., and another example is 6 h, 7.5 h, etc.; A1 is (950-1050) ° C, (1050-1250) ° C, etc., and another example is 1000 ° C, 1100 ° C, etc.;

[0078] Keep warm at A1 for H2 hours, H2 is (1~3);

[0079] For example, H2 is (1-2)h, (2-3)h, etc., and another example is 1.5h, 2.5h, etc.;

[0080] From A1 to A2, the heating time is H3, H3 is (1.5~2.5)h, A2 is (1300~1500)℃;

[0081] For example, H3 is (1.5-2.0) h, (2.0-2.5) h, etc., and another example is 1.5 h, 2.0 h, 2.4 h, etc.; A2 is (1300-1400) ° C, (1400-1500) ° C, etc., and another example is 1350 ° C, 1500 ° C, etc.;

[0082] Keep warm at A2 for H4 hours, H4 is (2.5~4.5);

[0083] For example, H4 is (2.5-3.0)h, (3.0-4.0)h, etc., and another example is 2.8h, 3.5h, etc.;

[0084] From A2 to A3, the heating time is H5, H5 is (1-3) h, A3 is (1700-1900) °C;

[0085] For example, H5 is (1-2)h, (2-3)h, etc., and another example is 1.6h, 2.0h, 2.5h, etc.; A3 is (1700-1800)℃, (1800-1900)℃, etc., and another example is 1750℃, 1850℃, etc.;

[0086] Keep warm at A3 for H6 hours, H6 is (1-3);

[0087] For example, H6 is (1-2)h, (2-3)h, etc., and another example is 1.5h, 2.5h, etc.;

[0088] From A3 to A4, the heating time is H7, H7 is (1-3)h, A4 is (2050-2250)℃;

[0089] For example, H7 is (1-2)h, (2-3)h, etc., and another example is 1.5h, 2.5h, etc.; A4 is (2050-2150)℃, (2150-2250)℃, etc., and another example is 2100℃, 2200℃, etc.;

[0090] Keep warm at A4 for H8 hours, H8 is (5-10);

[0091] For example, H8 is (5-7)h, (7-10)h, etc., and another example is 6h, 8h, etc.;

[0092] It is obtained by natural cooling from A4.

[0093] Step 4: Pressure processing:

[0094] 4.1 In the pressure processing step, the tungsten alloy sintered billet obtained after sintering is refined into an intermediate specification wire with a diameter of 1.5 to 3.5 mm;

[0095] 4.2 Then, the intermediate specification wire is subjected to oxidation annealing at (1200-1500)°C, and the annealing speed is (3-10) m / min; for example, the annealing speed is (3-7) m / min, (7-10) m / min, etc., and for example, 3 m / min, 5 m / min, 7 m / min, etc.; the oxidation annealing is (1200-1350)°C, (1350-1500)°C, etc., and for example, 1250°C, 1400°C, etc.;

[0096] 4.3 After oxidation annealing, continue to process the intermediate specification wire to the required wire diameter specification to obtain tungsten alloy wire (also known as black wire); among them, multiple passes of rotary forging and drawing are used for fine diameter processing; the oxidation annealing process is carried out in the oxidation annealing equipment, and the annealing speed refers to the speed of the wire passing through the annealing tank, which means the length of the wire passing through the annealing tank per unit time.

[0097] Step 5, white wire cleaning: Use electrolytic cleaning to clean the tungsten alloy wire into tungsten alloy white wire that can be processed into microwave oven heating device filament;

[0098] Step 6, Winding: Wind the white wire into a spring-shaped filament structure for heating devices to obtain tungsten alloy wire.

[0099] Important control points for the preferred embodiment of the preparation method:

[0100] (1) Oxidation annealing treatment of intermediate specifications:

[0101] The present application provides a specific treatment method for oxidation annealing in the above-mentioned pressure processing step, so that the initial recrystallization temperature of the tungsten alloy is controlled within the above-mentioned required range (48%Fc~56%Fc): a stress relief oxidation annealing at a temperature of 1200~1500°C is added at the middle specification of the wire of 1.5~3.5mm, so that the initial recrystallization temperature of the tungsten alloy wire is effectively controlled within 48%Fc~56%Fc; in this preparation process, if the oxidation annealing process is removed, the initial recrystallization temperature of the tungsten alloy wire exceeds 56%Fc, and the excessively high initial recrystallization temperature will be detrimental to the electron emission performance of the tungsten carbide alloy filament under the working conditions of the magnetron.

[0102] (2) By controlling the time from A1 to A2 and the sintering time at A2 (1300-1500°C) during the sintering process:

[0103] In the high-temperature sintering stage of the tungsten blank, the present invention provides a sintering process. By controlling the time of heating from A1 to A2 and the sintering time at A2 (1300-1500°C) in the sintering process, the sintering neck of the tungsten blank is allowed to grow rapidly, the holes are closed, and the oxide particles in the holes are prevented from being squeezed from the unclosed connecting channel to another hole during the shrinkage of the sintering cavity of the blank. On the basis of ensuring the density of the sintered blank, the size of the oxide particles of the sintered blank is controlled, thereby controlling the oxide size of the tungsten alloy wire or the filament after carbonization;

[0104] Among them, the oxide particle size distribution range of the tungsten alloy sintered billet obtained by the above sintering process is 100-2000nm, and the average size of the oxide particles is 600-1000nm, and the average size of the oxide particles of the tungsten alloy wire is (100-500)nm; optionally, the average size of the oxide particles can also be (100-300)nm, (300-500)nm, etc., for example, 200nm, 300nm, 450nm, etc.

[0105] Without the above sintering process, the oxide particle size distribution range of the sintered tungsten alloy billet is 400-5000nm, and the average size of the oxide particles is 1200-2000nm. The average size of the oxide particles of the further refined tungsten alloy wire is also relatively coarse (about 500-900nm).

[0106] Among them, the mechanism of the sintering process affecting the size of the oxides of the billet, tungsten alloy wire, and filament after carbonization, and the influence of the size of the oxides of tungsten alloy wire and filament after carbonization on the performance of the filament are as follows:

[0107] The reason why the oxide particle size is controlled within a smaller range is that the oxide particle size of the billet directly determines the oxide size of the tungsten alloy wire or the filament after carbonization. If the wire oxide particles are coarser, it will be more difficult for the particles to migrate to the filament surface during the use of the magnetron, which will make the balance of rare earth element loss and replenishment on the filament surface easier to break, making the magnetron electron emission more unstable.

[0108] The adjustment of sintering process affects the growth rate of sintering neck and pore closure of tungsten blank. The sintering process provided can reduce the possibility of oxide particle aggregation, thereby reducing the oxide particle size of sintered blank. Fig. 20 As shown, the specific principle of the high temperature sintering process is explained as follows:

[0109] The isostatically pressed green compact is a dense accumulation of powders with a porosity of about 35-45%. We can simply imagine these pores as holes with multiple channels connecting them, and the oxide particles are evenly distributed on the inner surface of the holes.

[0110] During the high-temperature sintering process, the tungsten particles bonded together form a "sintering neck". As the sintering temperature increases, the sintering neck continues to grow and blocks the channels connecting the holes, which produces isolated holes. These isolated holes will gradually become round, making the surface area inside the holes smaller, which in turn causes the originally similar-sized small oxide particles to gather together to form larger oxide particles. As the high-temperature sintering proceeds, the holes further shrink through diffusion, and the oxide particles distributed on the inner surface of the holes can only further gather to form one or several larger oxide particles.

[0111] Some of the smaller holes merge with adjacent large holes due to diffusion, or shrink before the connecting hole channels are closed. The oxide particles in these small holes will be pushed to the adjacent unclosed holes, making the unclosed holes contain more oxide than other places, which in turn causes the oxide particles to be larger than other places.

[0112] 1. Preferred component characteristics for tungsten alloy wire:

[0113] (1) Preferably, the tungsten alloy wire is composed of the following components: 0.0005-0.3wt% carbon element, 0.25-2.6wt% M element, 0.05-0.5wt% oxygen element, and the remainder is tungsten element and inevitable impurities.

[0114] Among them, the M element can be 1.28-2.6wt%, and the tungsten alloy filament made of the tungsten alloy material with this composition ratio is better for use in microwave ovens <800W. The M element can be 0.25-1.28wt%, and the tungsten alloy filament made of the tungsten alloy material with this composition ratio is better for use in microwave ovens >800W. Furthermore, the M element can be 0.25-0.86wt%, and the tungsten alloy filament made of the tungsten alloy material with this composition ratio is better for use in microwave ovens >1000W.

[0115] (2) The oxide of M is selected from one or more combinations of lanthanum oxide, yttrium oxide, scandium oxide, neodymium oxide, samarium oxide, lutetium oxide, cerium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, praseodymium oxide, erbium oxide, hafnium oxide, and zirconium oxide; the carbon element is present in the tungsten alloy material in the form of carbide or carbon element, and the carbide is selected from one or more combinations of lanthanum carbide, zirconium carbide, yttrium carbide, hafnium carbide, and tungsten carbide. For example, the oxide of M can be selected from lanthanum oxide, or a combination of lanthanum oxide and yttrium oxide, or a combination of lanthanum oxide and zirconium oxide, or a combination of lanthanum oxide and scandium oxide, or a combination of lanthanum oxide and hafnium oxide, etc.

[0116] Preferably, the components of the tungsten alloy material further include T, and the T is a solid solution metal element or a dispersed metal element, and the T is selected from at least one of K, Re, Mo, Fe, and Co. Further preferably, the mass content of the Re is less than 1000 ppm.

[0117] It should be noted that:

[0118] “La, Y, Sc, Nd, Sm, Lu, Ce, Gd, Tb, Dy, Ho, Pr, Er, Tm, Yb, Eu, Hf, Zr” in the text are element symbols in the periodic table, representing the metal elements lanthanum, yttrium, scandium, neodymium, samarium, lutetium, cerium, gadolinium, terbium, dysprosium, holmium, praseodymium, erbium, thulium, ytterbium, europium, hafnium and zirconium in the periodic table respectively; “K, Re, Mo, Fe, Co” in the text are element symbols in the periodic table, representing the metal elements potassium, rhenium, molybdenum, iron and cobalt in the periodic table respectively; W is the symbol of tungsten in the periodic table; C is the symbol of carbon in the periodic table; in addition, “M” and “T” are only reference symbols and do not represent elements in the periodic table and are only used for reference.

[0119] 2. Preferred structural features of the above tungsten alloy wire:

[0120] (1) The wire diameter of the above tungsten alloy wire can be 800μm or less:

[0121] In the pressure processing step, the tungsten alloy wire provided by the present invention has good processing performance and can be processed into wires with fine wire diameter specifications (i.e., fine wire diameter tungsten alloy wire), and the wire diameter tolerance can be controlled within a very small range.

[0122] Furthermore, the wire diameter of the tungsten alloy wire can reach 600μm or less, 550μm or less, or even 500μm or less. The wire diameter of the tungsten alloy wire can be 450-550μm, such as 470μm, 490μm, 500μm, 520μm, etc., or 700-800μm, such as 750μm, 760μm, 780μm, etc.

[0123] (2) The number of crack points detected by the above tungsten alloy wire is less than 5 (per 100 meters). Further, the number of crack points detected by the tungsten alloy wire can be less than 2 per 100 meters, such as 0 per 100 meters, 0.5 per 100 meters, 1 per 100 meters, etc.

[0124] Tungsten alloy wire has fewer crack points during flaw detection, a high filament yield rate, and is not prone to wire breakage.

[0125] 3. After the tungsten alloy wire is carbonized, a tungsten carbide alloy filament can be obtained. The present invention also provides the following preferred implementation scheme of the method for preparing the tungsten carbide alloy filament:

[0126] Step 1, cathode assembly: assemble the spring-shaped filament structure and components, ceramics, lead pieces and other parts into a cathode structure through heat treatment;

[0127] Step 2, welding: welding the filament structure in the cathode structure and the component end cap together;

[0128] Step 3, carbonization: placing the cathode structure into a carbonization tank for carbonization, introducing carbon-containing hydrocarbon gas after exhausting, and passing a direct current of a certain current value through the cathode structure for heating, so that the filament structure is carbonized in the hydrocarbon gas, and the filament structure is carbonized to form the tungsten alloy filament;

[0129] Step 4, white ball assembly: assemble the cathode structure, anode cylinder, antenna end cap and other components together;

[0130] Step 5, blackening treatment: exhaust the white ball, evacuate it, and age it at high temperature to complete the black ball manufacturing and launch performance activation;

[0131] Step 6, heating device assembly: Assemble the black ball, heat sink, magnet, tube shell, etc., and finally obtain a heating device component containing the above-mentioned tungsten alloy filament. In this way, the obtained heating device component can be installed in the equipment (such as a microwave oven) for use.

[0132] Among them, the tungsten alloy filament carbonization treatment of the present application is used to obtain a tungsten alloy filament such as Figure 1-5 As shown: it includes a substrate 100 and a carbonized layer 200 covering the periphery of the substrate 100; channels 210 are distributed on the carbonized layer 200, and the channels include a first channel 211 and a second channel 212;

[0133] At least part of the first channel 211 is distributed along the radial direction of the cross section of the filament; and / or at least part of the first channel 211 points to the center of the cross section of the filament. The second channel 212 divides the carbonized layer 200 into a layered structure stacked along the radial direction, and then divides the carbonized layer 200 into a block structure through the first channel 211 designed to intersect with it, and the carbonized layer 200 forms a layer block.

[0134] It should be noted that:

[0135] like Figure 1 The filament structure, Figure 2 The cross section of the filament and Figure 3 As shown in the longitudinal section of the filament, the “radial distribution along the cross section of the filament” and “at least part of the first channel 211 points to the center of the cross section of the filament” mentioned herein. For the radial distribution and the center of the circle: it means that the end point of the first channel 211 close to the substrate 100 and the end point close to the edge of the filament are connected to form a first straight line, and the angle between the first straight line and the tangent line of the intersection of the outer edge 220 of the filament is (60-90)°.

[0136] like Figure 5 As shown, for the "circumferential distribution along the cross section of the tungsten alloy filament" described in this article, the circumferential distribution means connecting the end points of the second channel 212 into a second straight line, and the angle between the second straight line and the straight line where the filament radial direction is located is (-45 to +45) degrees.

[0137] In the present invention, the first channel 211 is quasi-vertical and quasi-radially distributed to the outer edge 220 of the filament (i.e., the outer edge of the carbonized layer 200), but this does not mean that the first channel 211 is a straight structure, nor does it mean that the two end points of the first channel 211 need to pass through to the outer edge of the substrate 100 and the carbonized layer 200 (i.e., the outer edge 220 of the filament).

[0138] In the present invention, the second channel 212 is distributed along the annular direction or is cross-arranged with the first channel 211, which does not mean that the second channel 212 is a standard arc structure, and does not mean that the second channel 212 is continuously connected to pass through the entire outer ring. It can be a quasi-annular distribution composed of multiple sections of second channels 212 separated from each other, or a cross-distribution of multiple sections of second channels 212 separated from each other and the first channel 211, so that the carbonized layer 200 is divided into a layered structure stacked along the radial direction.

[0139] The present invention also provides the following embodiments and comparative examples:

[0140] The weight formula of the raw material components and the element ratio of the prepared filament material of the embodiments and comparative examples provided by the present invention are shown in Table 1 below:

[0141] Table 1

[0142]

[0143]

[0144]

[0145] Specifically, according to the formula in Table 1, the raw material components in the embodiment and the comparative example are prepared according to the following preparation method to prepare a tungsten alloy filament and a heating device:

[0146] Example 1

[0147] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H20 solution and stir to neutralize, spray the prepared mixed solution evenly onto the blue tungsten placed in the doping pot and stir; wherein, the volume ratio of lanthanum nitrate solution to ammonia NH3·H20 solution is 5:1;

[0148] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0149] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten-lanthanum doped powder with uniform doping and low impurity content is obtained;

[0150] 4. Reduce the tungsten-lanthanum doped powder into tungsten-lanthanum powder of suitable particle size in a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C;

[0151] 5. Put the obtained tungsten-lanthanum powder and tungsten carbide into a high-speed powder mixer for solid-solid powder mixing for 2 hours, and sieve to obtain mixed tungsten-lanthanum alloy powder;

[0152] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0153] 7. Use high temperature sintering method, and use the method of rapid heating and extended insulation time at the intermediate insulation point: the sintering temperature curve is:

[0154] From room temperature to A1, the heating time H1 is 6h, A1 is 1100℃; keep warm at A1 for H2 hours, H2 is 2; heat up from A1 to A2, the heating time is H3, H3 is 2h, A2 is 1400℃; keep warm at A2 for H4 hours, H4 is 3.5; heat up from A2 to A3, the heating time is H5, H5 is 2h, A3 is 1800℃; keep warm at A3 for H6 hours, H6 is 2; heat up from A3 to A4, the heating time is H7, H7 is 2h, A4 is 2100℃; keep warm at A4 for H8 hours, H8 is 6; cool naturally from A4, and you're done.

[0155] Among them, by controlling the medium frequency sintering time, the pore closing and shrinking speed of the billet is controlled, so as to obtain the oxide particle size <2.0μm and the density 18.0g / cm 3 Sintered billet.

[0156] 8. Use multiple rotary forging and drawing processes to process the 17mm diameter sintered billet into 2.0mm specification wire, and then perform oxidation annealing on the oxidation annealing equipment. The annealing conditions are: temperature 1400℃, annealing speed 5m / min; after annealing, continue to process into 0.52mm±0.005mm diameter rare earth tungsten alloy black wire;

[0157] Among them, the multi-pass rotary forging and drawing processing adopts conventional drawing process, and the process parameters are multi-pass rotary forging to a wire diameter specification of 3.7mm, then drawing to 2.0mm, and then further processing to 0.52±0.005mm tungsten lanthanum alloy black wire after annealing.

[0158] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten-lanthanum alloy white wire that can be processed into the filament of microwave oven heating devices;

[0159] 10. Wind 0.50mm tungsten-lanthanum alloy white wire into a spring-shaped cathode filament for heating devices, with 10 turns and a pitch of 1.29±0.03mm;

[0160] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0161] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0162] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0163] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0164] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0165] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0166] Example 2

[0167] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-yttrium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H2O solution and stir to neutralize, and evenly spray the prepared mixed solution onto the blue tungsten in the doping pot for stirring; wherein, the volume ratio of lanthanum nitrate-yttrium nitrate solution to ammonia NH3·H2O solution is 5:1.

[0168] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0169] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1-0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten lanthanum yttrium doped powder with uniform doping and low impurity content is obtained;

[0170] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten lanthanum yttrium doped powder is reduced into tungsten lanthanum yttrium powder of appropriate particle size;

[0171] 5. Put the obtained tungsten lanthanum yttrium powder and tungsten carbide into a high-speed powder mixer for solid-solid powder mixing for 2 hours, and sieve to obtain the mixed tungsten lanthanum yttrium alloy powder;

[0172] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0173] 7. Use high temperature sintering method, and use the method of rapid heating and extended insulation time at the intermediate insulation point: the sintering temperature curve is:

[0174] From room temperature to A1, the heating time is H1 for 5h, A1 is 950℃; keep warm at A1 for H2h, H2 is 3; from A1 to A2, the heating time is H3, H3 is 1.5h, A2 is 1300℃;

[0175] Keep warm at A2 for H4 hours, H4 is 4.5; heat up from A2 to A3, the heating time is H5, H5 is 1h, A3 is 1700℃; keep warm at A3 for H6 hours, H6 is 3; heat up from A3 to A4, the heating time is H7, H7 is 1h, A4 is 2050℃; keep warm at A4 for H8 hours, H8 is 10; cool naturally from A4, and you're done.

[0176] 8. The 17 mm diameter sintered billet was processed into a 2.0 mm specification wire by multiple rotary forging and drawing processes, and then oxidative annealing was performed on an oxidative annealing device, wherein the annealing conditions were: temperature 1200°C, annealing speed 3 m / min; after annealing, it was further processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum yttrium alloy black wire; other conditions were consistent with Example 1.

[0177] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten-lanthanum-yttrium alloy white wire that can be processed into microwave oven heating device filament;

[0178] 10. Wind 0.50mm tungsten-lanthanum-yttrium alloy white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0179] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0180] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0181] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0182] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0183] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0184] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0185] Example 3

[0186] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-zirconium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H2O solution and stir to neutralize, and evenly spray the prepared mixed solution onto the blue tungsten placed in the doping pot and stir; wherein, the ratio of lanthanum nitrate-zirconium nitrate solution to ammonia NH3·H2O solution is 5:1;

[0187] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0188] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten lanthanum zirconium doped powder with uniform doping and low impurity content is obtained;

[0189] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten lanthanum zirconium doped powder is reduced into tungsten lanthanum zirconium powder of appropriate particle size;

[0190] 5. The obtained tungsten lanthanum zirconium powder and tungsten carbide are placed in a high-speed powder mixer for solid-solid mixing for 2 hours, and then sieved to obtain a mixed tungsten lanthanum zirconium alloy powder;

[0191] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0192] 7. Use high temperature sintering method, and use the method of rapid heating and extended insulation time at the intermediate insulation point: the sintering temperature curve is:

[0193] From room temperature to A1, the heating time H1 is 8h, A1 is 1250℃; keep warm at A1 for H2 hours, H2 is 1; from A1 to A2, the heating time is H3, H3 is 2.5h, A2 is 1500℃;

[0194] Keep warm at A2 for H4 hours, H4 is 2.5; heat up from A2 to A3, the heating time is H5, H5 is 3h, A3 is 1900℃; keep warm at A3 for H6 hours, H6 is 1; heat up from A3 to A4, the heating time is H7, H7 is 3h, A4 is 2250℃; keep warm at A4 for H8 hours, H8 is 5; cool naturally from A4, and you're done.

[0195] 8. The 17mm diameter sintered billet is processed into 2.0mm specification wire by multi-pass rotary forging and drawing, and then oxidized annealing is carried out on the oxidation annealing equipment, wherein the annealing conditions are: temperature 1500℃, annealing speed 10m / min; after the annealing is completed, it is further processed into 0.52mm±0.005mm diameter tungsten lanthanum zirconium alloy black wire;

[0196] 9. The 0.52 mm black wire is cleaned by electrolytic cleaning to become a 0.50 mm ± 0.005 mm tungsten lanthanum zirconium alloy white wire that can be processed into a filament of a microwave oven heating device; other conditions are consistent with Example 1.

[0197] 10. Wind 0.50mm tungsten lanthanum zirconium alloy white wire into a spring-shaped cathode filament for the heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0198] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0199] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0200] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0201] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0202] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0203] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0204] Example 4

[0205] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-scandium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H2O solution and stir to neutralize, spray the prepared mixed solution evenly onto the blue tungsten placed in the doping pot and stir; wherein, the ratio of lanthanum nitrate-scandium nitrate solution to ammonia NH3·H2O solution is 5:1.

[0206] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0207] 3. Under vacuum, the powder is dried by steam heating, with a steam pressure of 0.1-0.3MPa and a vacuum degree in the pot of ≤-0.02MPa, and finally a tungsten-lanthanum-sc doped powder with uniform doping and low impurity content is obtained;

[0208] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten-lanthanum-scandium doped powder is reduced into tungsten-lanthanum-scandium powder of appropriate particle size;

[0209] 5. Put the obtained tungsten lanthanum scandium powder and tungsten carbide into a high-speed powder mixer for solid-solid powder mixing for 2 hours, and sieve to obtain the mixed tungsten lanthanum scandium alloy powder;

[0210] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0211] 7. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0212] 8. Using multiple rotary forging and drawing processes, the 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum scandium alloy black wire; wherein the process and conditions of this step are consistent with those of Example 1;

[0213] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten lanthanum scandium alloy white wire that can be processed into microwave oven heating device filament;

[0214] 10. Wind 0.50mm tungsten-lanthanum-scandium alloy white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0215] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0216] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0217] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0218] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0219] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0220] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0221] Example 5

[0222] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-hafnium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H2O solution and stir to neutralize, and evenly spray the prepared mixed solution onto the blue tungsten placed in the doping pot and stir; wherein, the ratio of lanthanum nitrate-hafnium nitrate solution to ammonia NH3·H2O solution is 5:1;

[0223] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0224] 3. Under vacuum, the powder is dried by steam heating, with a steam pressure of 0.1-0.3MPa and a vacuum degree in the pot of ≤-0.02MPa, to finally obtain tungsten, lanthanum and hafnium doped powder with uniform doping and low impurity content;

[0225] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten lanthanum hafnium doped powder is reduced into tungsten lanthanum hafnium powder with a suitable particle size and a content of 0.3% La2O3+0.2% HfO2;

[0226] 5. The obtained tungsten lanthanum hafnium powder and tungsten carbide are put into a high-speed powder mixer for solid-solid powder mixing for 2 hours, and sieved to obtain a mixed tungsten lanthanum hafnium alloy powder with a content of 0.3% La203+0.2% Hf02+0.5% WC;

[0227] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0228] 7. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0229] 8. The 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum hafnium alloy black wire by multiple rotary forging and drawing processes; wherein the process and conditions of this step are consistent with those of Example 1;

[0230] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten lanthanum hafnium alloy white wire that can be processed into microwave oven heating device filament;

[0231] 10. Wind 0.50mm tungsten-lanthanum-hafnium alloy white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0232] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0233] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0234] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0235] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0236] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0237] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0238] Example 6

[0239] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-hafnium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H2O solution and stir to neutralize, and evenly spray the prepared mixed solution onto the blue tungsten placed in the doping pot and stir; wherein, the ratio of lanthanum nitrate-hafnium nitrate solution to ammonia NH3·H2O solution is 5:1;

[0240] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0241] 3. Under vacuum, the powder is dried by steam heating, with a steam pressure of 0.1-0.3MPa and a vacuum degree in the pot of ≤-0.02MPa, to finally obtain tungsten, lanthanum and hafnium doped powder with uniform doping and low impurity content;

[0242] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten lanthanum hafnium doped powder is reduced into tungsten lanthanum hafnium powder with a suitable particle size and a content of 2.0% La2O3+1.0% HfO2;

[0243] 5. The obtained tungsten lanthanum hafnium powder and tungsten carbide are put into a high-speed powder mixer for solid-solid powder mixing for 2 hours, and sieved to obtain a mixed tungsten lanthanum hafnium alloy powder with a content of 2.0% La203+1.0% Hf02+2.0% WC;

[0244] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0245] 7. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0246] 8. The 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum hafnium alloy black wire by multiple rotary forging and drawing processes; wherein the process and conditions of this step are consistent with those of Example 1;

[0247] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten lanthanum hafnium alloy white wire that can be processed into microwave oven heating device filament;

[0248] 10. Wind 0.50mm tungsten-lanthanum-hafnium alloy white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0249] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0250] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0251] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane gas) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0252] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0253] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0254] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0255] Example 7

[0256] 1. According to the formula in Table 1, add a certain amount of lanthanum nitrate to 5L deionized water, stir for 10 minutes to fully dissolve, then add 1L ammonia NH3·H20 solution and stir to neutralize, spray the prepared mixed solution evenly onto the blue tungsten placed in the doping pot and stir; wherein, the volume ratio of lanthanum nitrate solution to ammonia NH3·H20 solution is 5:1;

[0257] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0258] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten-lanthanum doped powder with uniform doping and low impurity content is obtained;

[0259] 4. Reduce the tungsten-lanthanum doped powder into tungsten-lanthanum powder of suitable particle size in a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C;

[0260] 5. According to the formula in Table 1, add 5L of deionized water into the doping pot and heat it to 80°C, then add a certain amount of ammonium rhenate, stir for 10 minutes to fully dissolve, add a certain amount of tungsten lanthanum powder into the ammonium rhenate solution and stir for 30 minutes, then dry the powder by steam heating under vacuum, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally obtain rhenium-doped tungsten lanthanum powder with uniform doping and low impurity content;

[0261] 6. Reduce the rhenium-doped tungsten-lanthanum powder into tungsten-lanthanum-rhenium alloy powder with a particle size of 1.5 μm in a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C;

[0262] 7. The obtained tungsten-lanthanum-rhenium alloy powder and tungsten carbide are placed in a high-speed powder mixer for solid-solid powder mixing for 2 hours, and the mixed tungsten-lanthanum-rhenium alloy powder is obtained by sieving;

[0263] 8. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0264] 9. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0265] 10. The 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum rhenium alloy black wire by multiple rotary forging and drawing processes; wherein the process and conditions of this step are consistent with those of Example 1;

[0266] 11. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten lanthanum rhenium alloy white wire that can be processed into microwave oven heating device filament;

[0267] 12. Wind 0.50mm tungsten-lanthanum-rhenium alloy white wire into a spring-shaped cathode filament for a heating device, with 10 turns and a pitch of 1.29±0.03mm;

[0268] 13. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0269] 14. Weld the filament in the cathode structure to the end cap of the assembly.

[0270] 15. Place the cathode structure into the carbonization tank for carbonization, exhaust the gas, introduce carbon-containing hydrocarbon gas (specifically methane), and heat the cathode with a direct current of a certain current value (current value is 16A) to complete the carbonization of the filament in the hydrocarbon gas.

[0271] 16. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0272] 17. The white ball is evacuated and aged at high temperature to complete the manufacture of the black ball and activate its launch performance.

[0273] 18. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0274] Comparative Example 1:

[0275] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of thorium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H20 solution and stir to neutralize, and evenly spray the prepared mixed solution onto the blue tungsten placed in the doping pot and stir; the ratio of thorium nitrate solution to ammonia NH3·H20 solution is 5:1;

[0276] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0277] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally thorium tungsten doped powder with uniform doping and low impurity content is obtained;

[0278] 4. The thoriated tungsten doped powder is reduced into thoriated tungsten powder with a particle size of 1.5 μm in a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C;

[0279] 5. The obtained thoriated tungsten powder is put into a V-type powder mixer for mixing for 2 hours, and then sieved to obtain the mixed thoriated tungsten powder;

[0280] 6. Use isostatic pressing to press 1.5μm thoriated tungsten powder into a compact weighing 3.0kg at a pressure of 180MPa, and pre-sinter the compact at low temperature in a hydrogen atmosphere to increase the strength of the compact;

[0281] 7.Use high temperature sintering to obtain thorium oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0282] 8. The 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter thoriated tungsten alloy black wire by multiple rotary forging and drawing processes; wherein the process and conditions of this step are consistent with those of Example 1;

[0283] 98. Use electrolytic cleaning to clean 0.52mm black wire into 0.50mm±0.005mm thoriated tungsten alloy white wire that can be processed into microwave oven heating device filament;

[0284] 10. Wind 0.50mm thoriated tungsten white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0285] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0286] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0287] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (methane gas) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0288] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0289] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0290] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0291] Comparative Example 2:

[0292] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-yttrium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H20 solution and stir to neutralize, spray the prepared mixed solution evenly onto the blue tungsten placed in the doping pot and stir; wherein, the ratio of lanthanum nitrate-yttrium nitrate solution to ammonia NH3·H20 solution is 5:1.

[0293] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0294] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1-0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten lanthanum yttrium doped powder with uniform doping and low impurity content is obtained;

[0295] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten lanthanum yttrium doped powder is reduced into tungsten lanthanum yttrium powder with a particle size of 1.5 μm;

[0296] 5. The obtained tungsten lanthanum yttrium powder is put into a V-type powder mixer for mixing for 2 hours, and then sieved to obtain a mixed tungsten lanthanum yttrium alloy powder;

[0297] 6. Use isostatic pressing to press the 1.5 μm tungsten-lanthanum-yttrium alloy powder into a green compact weighing 3.0 kg at a pressure of 180 MPa, and pre-sinter the green compact at a low temperature in a hydrogen atmosphere to increase the green compact strength;

[0298] 7. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0299] 8. Using multiple rotary forging and drawing processes, the 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum yttrium alloy black wire; wherein the process and conditions of this step are consistent with those of Example 1;

[0300] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten-lanthanum-yttrium alloy white wire that can be processed into microwave oven heating device filament;

[0301] 10. Wind 0.50mm tungsten-lanthanum-yttrium alloy white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0302] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0303] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0304] 13. Place the cathode structure into the carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (specifically methane) after exhausting, and apply direct current of a certain current value (current value is 16A) to heat the cathode to complete carbonization of the filament in the hydrocarbon gas.

[0305] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0306] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0307] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0308] Comparative Example 3:

[0309] 1. According to the formula in Table 1, add 5L of deionized water to a certain amount of lanthanum nitrate-scandium nitrate solution, stir for 10 minutes to fully dissolve, then add 1L of ammonia NH3·H2O solution and stir to neutralize, spray the prepared mixed solution evenly onto the blue tungsten placed in the doping pot and stir; wherein, the ratio of lanthanum nitrate-scandium nitrate solution to ammonia NH3·H2O solution is 5:1.

[0310] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0311] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1-0.3MPa, and the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten lanthanum scandium doped powder with uniform doping and low impurity content is obtained;

[0312] 4. In a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C, the tungsten-lanthanum-scandium doped powder is reduced into tungsten-lanthanum-scandium powder with a particle size of 1.5 μm;

[0313] 5. The obtained tungsten lanthanum scandium powder is put into a V-type powder mixer for mixing for 2 hours, and then sieved to obtain a mixed tungsten lanthanum scandium alloy powder;

[0314] 6. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0315] 7. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0316] 8. Using multiple rotary forging and drawing processes, the 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum scandium alloy black wire; wherein the process and conditions of this step are consistent with those of Example 1;

[0317] 9. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten lanthanum scandium alloy white wire that can be processed into microwave oven heating device filament;

[0318] 10. Wind 0.50mm tungsten-lanthanum-scandium alloy white wire into a spring-shaped cathode filament for a heating device; the number of turns is 10, and the pitch is 1.29±0.03mm;

[0319] 11. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600 degrees Celsius.

[0320] 12. Weld the filament in the cathode structure to the end cap of the assembly.

[0321] 13. Place the cathode structure into a carbonization tank for carbonization, introduce carbon-containing hydrocarbon gas (preferably methane gas) after exhausting, and apply direct current of a certain current value (preferably 16A) to the cathode for heating, so that the filament is carbonized in the hydrocarbon gas.

[0322] 14. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0323] 15. Exhaust the white ball, evacuate it, and perform high-temperature aging to complete the manufacture of the black ball and activate its launch performance.

[0324] 16. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component (i.e., heating device) containing the above-mentioned filament, and put it into a microwave oven for use.

[0325] Comparative Example 4

[0326] 1. According to the formula in Table 1, add a certain amount of lanthanum nitrate to 5L deionized water, stir for 10 minutes to fully dissolve, then add 1L ammonia NH3·H2O solution and stir to neutralize, spray the prepared mixed solution evenly onto the blue tungsten placed in the doping pot and stir; wherein, the volume ratio of lanthanum nitrate solution to ammonia NH3·H2O solution is 5:1;

[0327] 2. Evacuate the doping pot and heat it with water (heating temperature 80°C, vacuum degree -0.025MPa), stirring while heating;

[0328] 3. Under vacuum, the powder is dried by steam heating, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally tungsten-lanthanum doped powder with uniform doping and low impurity content is obtained;

[0329] 4. Reduce the tungsten-lanthanum doped powder into tungsten-lanthanum powder of suitable particle size in a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C;

[0330] 5. According to the formula in Table 1, add 5L of deionized water into the doping pot and heat it to 80°C, then add a certain amount of ammonium rhenate, stir for 10 minutes to fully dissolve, add a certain amount of tungsten lanthanum powder into the ammonium rhenate solution and stir for 30 minutes, then dry the powder by steam heating under vacuum, the steam pressure is 0.1~0.3MPa, the vacuum degree in the pot is ≤-0.02MPa, and finally obtain rhenium-doped tungsten lanthanum powder with uniform doping and low impurity content;

[0331] 6. Reduce the rhenium-doped tungsten-lanthanum powder into tungsten-lanthanum-rhenium alloy powder with a particle size of 1.5 μm in a reduction furnace with four temperature zones at 650°C, 750°C, 850°C and 900°C;

[0332] 7. The obtained tungsten-lanthanum-rhenium alloy powder and tungsten carbide are placed in a high-speed powder mixer for solid-solid powder mixing for 2 hours, and the mixed tungsten-lanthanum-rhenium alloy powder is obtained by sieving;

[0333] 8. The powder with a particle size of 1.5 μm was pressed into a green compact with a single weight of 3.0 kg at a pressure of 180 MPa by isostatic pressing, and the green compact was pre-sintered at a low temperature in a hydrogen atmosphere to increase the strength of the green compact;

[0334] 9. Use high temperature sintering to obtain oxide particles with a particle size of <2.0μm and a density of 18.0g / cm 3 The sintered billet; wherein the process and conditions of this step are consistent with those of Example 1;

[0335] 10. The 17 mm diameter sintered billet is processed into a 0.52 mm ± 0.005 mm diameter tungsten lanthanum rhenium alloy black wire by multiple rotary forging and drawing processes; wherein the process and conditions of this step are consistent with those of Example 1;

[0336] 11. Use electrolytic cleaning to clean the 0.52mm black wire into 0.50mm±0.005mm tungsten lanthanum rhenium alloy white wire that can be processed into microwave oven heating device filament;

[0337] 12. Wind 0.50mm tungsten-lanthanum-rhenium alloy white wire into a spring-shaped cathode filament for a heating device, with 10 turns and a pitch of 1.29±0.03mm;

[0338] 13. Assemble the filament, components, ceramics, lead pieces and other parts into a cathode structure through heat treatment at a temperature of 600°C.

[0339] 14. Weld the filament in the cathode structure to the end cap of the assembly.

[0340] 15. Place the cathode structure into the carbonization tank for carbonization, exhaust the gas, introduce carbon-containing hydrocarbon gas (specifically methane), and heat the cathode with a direct current of a certain current value (current value is 16A) to complete the carbonization of the filament in the hydrocarbon gas.

[0341] 16. White ball assembly: Assemble the cathode structure, anode cylinder, antenna end cap and other components together.

[0342] 17. The white ball is evacuated and aged at high temperature to complete the manufacture of the black ball and activate its launch performance.

[0343] 18. Assemble the black ball, heat sink, magnet, tube shell, etc. to finally obtain the heating device component containing the above-mentioned filament, and put it into a microwave oven for use.

[0344] Comparative Example 5

[0345] The difference between this comparative example and Example 1 is only that:

[0346] In this comparative example, in the multi-pass rotary forging and drawing process, the sintered billet with a diameter of 17 mm is directly processed into a tungsten-lanthanum-tungsten alloy black wire with a diameter of 0.52 mm ± 0.005 mm, and the wire diameter of the intermediate specification is not processed by the oxidation annealing process. Other processes and process conditions are consistent with those in Example 1.

[0347] Comparative Example 6

[0348] The difference between this comparative example and Example 1 is only that:

[0349] In this comparative example, the temperature rise curve of the high temperature sintering is: from room temperature to A1, the temperature rise time H1 is 6h, A1 is 1100℃; keep warm at A1 for H2 hours, H2 is 2h; heat from A1 to A2, the temperature rise time is H3, H3 is 3h, A2 is 1400℃; keep warm at A2 for H4 hours, H4 is 2h; heat from A2 to A3, the temperature rise time is H5, H5 is 2h, A3 is 1800℃; keep warm at A3 for H6 hours, H6 is 2h; heat from A3 to A4, the temperature rise time is H7, H7 is 2h, A4 is 2100℃; keep warm at A4 for H8 hours, H8 is 6h; cool naturally from A4, and obtain. Other processes and process conditions are consistent with those in Example 1.

[0350] The tungsten alloy wires, tungsten alloy filaments and devices (microwave ovens) containing the filament components prepared in the above embodiments and comparative examples were tested for relevant performance indicators under the same test conditions. The test results are shown in Tables 2-7 below:

[0351] Table 2

[0352]

[0353]

[0354] Table 3

[0355]

[0356] Note: The yield rate statistics refer to the yield rate from billet to finished filament.

[0357] Table 4

[0358]

[0359]

[0360] Table 5 Data comparison table of Example 1, Comparative Example 1 (Thorium Tungsten) and Comparative Examples 5-6

[0361]

[0362]

[0363] Table 6 Comparison of the results of Example 1 and Comparative Example 6

[0364] project Initial recrystallization temperature Fc% 80% Fc recrystallized grain size μm Example 1 50% FC 5.05 Comparative Example 5 60% FC 2.12

[0365] Table 7 Comparison of the results of Example 1 and Comparative Example 7

[0366]

[0367] In Table 2-7, the test standard for the recrystallization temperature range item is GB T 23272-2009 Tungsten wire for lighting and electronic equipment; FC is the size of the fusing current, and the conversion method for FC% and Celsius is as follows: Fig.19 The high temperature performance test method in Article 4.3.2.2 of the national standard GB / T23272-2009 for tungsten filaments for lighting and electronic equipment shows a reference relationship between FC% and temperature, which can be used for conversion; the electron work function is measured according to the Richardson linear method; the working life of the tungsten alloy filament is tested according to the life test method in Article 6.5.2 of the national standard GB / T 23152-2008 for heating devices for household microwave ovens, wherein the standard requires continuous operation of heating devices for microwave ovens to be >500h; wherein, the preparation process of steps 10-14 in the embodiment and the test nodes for each test item are as follows: Fig.18 shown.

[0368] 1. Comparing Example 1 with Comparative Example 1, Comparative Example 1 is a thoriated tungsten filament, and the initial recrystallization temperature of Comparative Example 1 is lower than the range defined in this application:

[0369] The metallographic conditions of Example 1 and Comparative Example 1 at different fusing currents are as follows Figure 6-12 As shown: it can be clearly seen that the recrystallization temperature of Example 1 is 50% FC (about 2120°C), and the recrystallization temperature of Comparative Example 1 is 46% FC (about 2020°C). It can be seen that the initial recrystallization temperature of the filament material of the present invention is higher than that of the original thoriated tungsten wire material;

[0370] 1.1. The effect of the recrystallization starting temperature on the grain width of the carbide layer 200

[0371] The grain size of the filament after carbonization in Example 1 and Comparative Example 1 is as follows: Figure 13-14 As shown: Fig.14 In Example 1, the filament structure after carbonization is still a fine-grained structure. Fig.13 The grains of the filament structure after carburization in Comparative Example 1 are obviously larger. From the data, the number of grains of the tungsten substrate 100 after carburization in Example 1 is 4000 / mm 2 , Comparative Example 1 is 100 pieces / mm 2 The grain width of the carbonized layer 200 of Example 1 is 6.83 μm, and that of Comparative Example 1 is 9.81 μm.

[0372] 1.2. The initial recrystallization temperature affects the grain width of the tungsten alloy filament, thereby affecting the channel distribution of the carbide layer 200, thereby affecting the emission performance:

[0373] The distribution of the channels 210 of the filaments after carbonization in Example 1 and Comparative Example 1 is as follows: Figure 15-17 As shown, Fig.15In the carbonized layer 200 of the cross section of the filament after carbonization in the embodiment 1 shown, there are many first channels 211 quasi-vertical to the edge of the filament, and the second channels 212 intersect with the first channels to form a quasi-ring distribution, and the carbonized layer 200 forms a layer block. Fig.16 In the carbonized layer 200 of the longitudinal section of the filament after carbonization in the embodiment 1 shown, there are many first channels 211 which are perpendicular to the edge of the filament; Fig.17 In the carbonized layer 200 of the cross-section of the filament after carbonization in Comparative Example 1, the number of first channels 211 perpendicular to the edge of the filament is significantly reduced, and there are very few parallel second channels 212. The reason for this is that the grain width of the carbonized layer in Comparative Example 1 is relatively large, and the number of its channels 210 is related to the size of the grains, and the grain size affects the formation of the channels 210.

[0374] In Example 1 of the present invention, the layered structure in the carbonized layer 200 separated by the second channel 212 is where the oxide of M is distributed, the first channel 211 is vertically distributed with the edge of the filament, connecting the inside of the substrate 100, the second channel 212 and the edge of the filament, and the second channel 212 is combined with the first channel 211, which is beneficial to the outward migration of rare earth atoms and timely replenishment of rare earth elements evaporated from the surface, thereby improving the stability of material emission.

[0375] 1.3. The initial recrystallization temperature affects the grain width of the tungsten carbide alloy filament, thus affecting the wire breakage rate, etc.:

[0376] The recrystallization temperature of the thoriated tungsten filament is relatively low. After the filament is carburized, the recrystallized grains of the tungsten matrix of the filament will be coarse, and the filament will be brittle, resulting in poor anti-seismic performance of the magnetron, and the filament is more likely to break, which in turn causes the magnetron to fail to work. Among them, it can be clearly seen from the data of Comparative Example 1 that the breakage rate and working performance of the thoriated tungsten filament are significantly worse than those of Example 1.

[0377] Similarly, when the recrystallization temperature of the tungsten alloy wire of the present application is lower than the specified range of the present application (48%Fc~56%Fc), the grains of the recrystallized structure of the tungsten matrix of the filament will be coarser after the filament is carburized, and the filament will be brittle, resulting in poor seismic performance of the magnetron, the filament will be more likely to break, and the breakage rate will be worse than that of the embodiment.

[0378] 2. Comparison of Example 2 and Comparative Example 2, Example 4 and Comparative Example 3:

[0379] 2.1 The difference between Example 2 and Comparative Example 2 is that: Comparative Example 2 does not add carbide raw materials, and there is no carbon in its components; By comparing the results of the two, it can be seen that: compared with Example 2, the recrystallization temperature of Comparative Example 2 is lower, the grain width of the carbide layer is larger, and the carbide layer 200 has a block structure, which is reflected in the performance: its emission performance stability deteriorates, the electron emission performance deteriorates, and the working life is shortened.

[0380] 2.2 The difference between Example 4 and Comparative Example 3 is that: Comparative Example 3 does not add carbide raw materials, and there is no carbon in its components; By comparing the results of the two, it can be seen that: compared with Example 4, the recrystallization temperature of Comparative Example 3 is lower, the grain width of the carbide layer is larger, and the carbide layer 200 has a block structure, which is reflected in the performance: its emission performance stability deteriorates, the electron emission performance deteriorates, and the working life is shortened.

[0381] The mechanism is analyzed as follows: in the embodiment of the present invention, by adding one or more oxides and carbides of M or carbon, the oxides and carbides of M in the tungsten matrix will react at high temperature, and the generated M metal atoms are much smaller than the particles of M oxides. The migration and diffusion speed of M metal atoms in the tungsten matrix will increase. Therefore, compared with the thoriated tungsten filament, it can achieve the same or even higher electron emission capability at a lower operating voltage (excitation temperature). Comparative Examples 2-3 do not add carbon raw materials, and obviously cannot achieve the above effect, and their electron emission performance deteriorates.

[0382] 4. Comparative Example 7 and Comparative Example 4:

[0383] The difference between Example 7 and Comparative Example 4 is that the Re content of Comparative Example 4 exceeds the specified range of this application; by comparing the results of the two, it can be seen that the working temperature of Comparative Example 4 becomes higher and the working life becomes shorter. The inventor analyzed that rhenium has the functions of purifying grain boundaries and strengthening the solid solution of rhenium and tungsten. However, the addition of rhenium content exceeds the specified range of this application, the rhenium content is too high, the strengthening effect is too large, and the work hardening is too large, which makes the wire more prone to cracks. It can be clearly seen in the wire flaw detection data that the number of flaw detection cracks in Example 7 is 0.8-1.5 / 100 meters, while that in Comparative Example 5 is 6-10 / 100 meters.

[0384] 5. Comparative Example 1 and Comparative Examples 5-6:

[0385] 5.1. Compared with Example 1, the initial recrystallization temperature of Comparative Example 5 is higher than the range specified in this application: Compared with Example 1, Comparative Example 5 does not use oxidation annealing to control the initial recrystallization temperature of the tungsten alloy wire within a certain range. The initial recrystallization temperature of Comparative Example 5 becomes higher (higher than the range specified in this application), the number of cracks per 100 meters increases, and the yield rate decreases. It can be seen that for the initial recrystallization temperature, it is not that increasing it blindly will lead to better results. If it is higher than the range specified in this application, it will also bring adverse effects.

[0386] 5.2. Comparing Example 1 and Comparative Example 6, the average size of the oxide particles in Comparative Example 6 exceeds the range specified in the present application: Compared with Example 1, the average size of the oxide particles in the billet in Comparative Example 6 becomes larger, and the average size of the oxide particles in the 0.5 mm wire cross section becomes larger. The size of the oxide particles will affect the processing performance, that is, the processing yield and the level of flaw detection. Therefore, the number of crack points per 100 meters of the wire produced in this comparative example increases, and the yield decreases.

[0387] In summary, it can be clearly concluded from the test results of the embodiments and comparative examples that:

[0388] 1. There is a carbonization process in the preparation of the filament. The carbonization temperature is 2000-2200℃. The original thoriated tungsten filament is carbonized at this temperature, and the grain structure will show recrystallization. The grains are coarse, which makes the filament very easy to break after carbonization. If the vibration in the production process is slightly larger, the wire will break (the wire breaking rate is about 20,000-30,000 ppm).

[0389] The recrystallization temperatures measured in Examples 1-7 are between 48% FC (about 2070°C) and 52% FC (about 2180°C), and the recrystallization temperature of Comparative Example 1 is 46% FC (about 2020°C). The initial recrystallization temperature of the filament material produced by the present invention is higher than that of the original thoriated tungsten filament, and the filament structure after carbonization is still a fine-grained structure (the grain size of the embodiments of the present invention is significantly smaller than that of the comparative example), and the filament with a fine-grained structure is not easy to break;

[0390] 2. Through the observation of the cross-sectional structure, longitudinal section structure and the carbide layer 200 of the longitudinal planed section structure, the recrystallization temperature of the tungsten alloy wire of the present invention is controlled within a certain range, and its initial recrystallization temperature is higher than that of the original thoriated tungsten wire, and the filament structure after carburization is still a fine-grained structure;

[0391] Compared with the thoriated tungsten filament, the grain size of the carbide layer 200 of the thoriated tungsten lanthanum filament in the present invention is smaller than that of the thoriated tungsten filament, and the grain width is slightly narrower than that of the thoriated tungsten, so that the number of channels 210 in the carbide layer 200 of the present invention is more, and the organization of the carbide layer 200 at different positions in the filament provided by the present invention has an organization similar to the cross shape of the first channel 211 and the second channel 212, forming a layer block structure. The first channel 211 is vertically distributed with the edge of the filament, connecting the second channel 212, the inside of the substrate 100 and the edge of the filament, which is conducive to the outward migration of rare earth atoms and timely replenishment of the rare earth element evaporated from the surface, and improving the stability of the material emission. It can be clearly seen from the emission performance stabilization time data in the test results that there are differences in the emission performance of the filaments. Among them, the emission performance of the filament of the present invention is stable, which is equivalent to that of the traditional thoriated tungsten filament. It can be seen that the tungsten carbide alloy material of the present invention replenishes the rare earth element evaporated from the surface through the stable outward migration of rare earth, thereby improving the stability of the material emission. Without adding thorium element, it can also achieve the stable emission capability of the traditional thorium tungsten filament, solve the problem of poor stable emission capability of the existing thorium-free tungsten filament, and does not have the radioactive pollution problem of the traditional thorium tungsten filament.

[0392] 3. It can be clearly seen from the test results that the processing performance of the filament material of the present invention is better than that of the original thoriated tungsten, the number of flaw detection cracks is less (when the filament wire diameter can reach 500μm, the number of flaw detection cracks of the filament is less than 2 / 100 meters), the processing yield is high, the wound filament is not easy to break, the production efficiency is improved, and the wire material has fewer cracks, and the proportion of broken wires during carbonization of the manufactured filament is also less.

[0393] 4. It can be clearly seen from the electron emission performance parameters in the test results that the DC emission capacity of the heating device made of the filament of the present invention is nearly twice that of the thoriated tungsten filament (Comparative Example 1), so that the heating device made of the filament provided by the present invention can excite electrons at a lower voltage (Note: According to the use of heating devices in this field, the starting voltage of the thoriated tungsten heating device must be at least 2.0V. In order to ensure the starting voltage, the working voltage is set at 3.3V, while the starting voltage of Example 1 is 1.4V, and the working voltage can be in the range of 1.6 to 1.8V).

[0394] The operating temperature of the heating device of the present invention can be reduced from 1500-1600°C to 1100-1500°C, such as 1200-1300°C, while the operating temperature of the traditional thoriated tungsten filament is 1600-1900°C. Therefore, the energy consumption and life of the heating device provided by the present invention are improved.

[0395] In summary, the above technical solution provided by the present invention includes at least the following working principles or mechanisms and beneficial effects:

[0396] (1) The present invention dopes the tungsten matrix powder with oxides and carbides of M and controls the initial recrystallization temperature of the material so that extremely fine grains can still be obtained at the same carburization temperature as that of thoriated tungsten. This can improve the processing performance of the material, reduce the wire breakage rate during the production and use of the material, and reduce the electronic work function of the material. This can not only reduce the wire breakage rate and increase the yield rate to reduce production and transportation costs, but also effectively increase the service life of the filament, making its service life reach and far exceed the service life of the existing thoriated tungsten filament.

[0397] (2) The initial recrystallization temperature of the filament material provided by the present invention is between 48% FC (about 2070°C) and 56% FC (about 2290°C). Therefore, after carburization at a temperature of 2000-2100°C, the grains of the tungsten matrix 100 are relatively fine, and the brittleness of the carburized filament is less than that of the traditional thoriated tungsten filament material, which can reduce the wire breakage rate of customers during production and use.

[0398] (3) Analysis of the influence of the average size of oxide particles: By controlling the average size of the oxide particles of the tungsten alloy wire within the specified range of this application, it is beneficial to further improve the processing yield and flaw detection level of the wire. (4) The processing performance of the filament material of the present invention is better than that of the original thoriated tungsten, with fewer flaw detection crack points (when the filament wire diameter can reach 500μm, the number of flaw detection crack points of the filament is less than 2 / 100 meters), the processing yield rate is high, the wound filament is not easy to break, the production efficiency is improved, and the wire has fewer crack points, and the proportion of carbonized broken wires in the manufactured filament is also low.

[0399] (5) In the filament material provided by the present invention, the oxide of M (such as lanthanum oxide particles) has good plasticity. As the pressure processing proceeds, the oxide particles of M will become thin and long, and exist in a linear or quasi-linear shape; while the thorium oxide in the traditional thoriated tungsten material has poor plasticity. When the thoriated tungsten is processed to a certain extent, the thorium oxide will break. As the processing proceeds, the thorium oxide will appear as a string of particles; the types of rare earth oxides added by the present invention and the changes in morphology and structure during the refinement process make the filament material have good processing performance. When preparing the wire material for winding the filament, the wire diameter of the filament material can be refined to 500μm or less, and the number of crack points in the flaw detection is effectively reduced, thereby improving the yield rate.

[0400] (6) The operating temperature of the heating device made of the tungsten alloy filament provided by the present invention (i.e., the operating temperature of the filament) can be reduced from 1500-1600°C to 1100-1500°C, such as within the range of 1200-1300°C, and still maintain a good working condition; while the operating temperature of the traditional thoriated tungsten filament is 1600-1900°C. Therefore, the energy consumption and life of the filament provided by the present invention and the heating device made therefrom will be improved.

[0401] In summary:

[0402] The filament provided by the present invention adds one or more oxides and carbides or carbon elements of M into the tungsten matrix 100. The combination of the oxides and carbides or carbon elements can increase the diffusion rate of the material in the matrix 100. Compared with the thoriated tungsten filament, the filament can achieve the same or even higher electron emission capability at a lower operating voltage (excitation temperature).

[0403] The present invention dopes oxides and carbides of M into tungsten matrix powder and controls the initial recrystallization temperature of the material so that extremely fine grains can still be obtained at the same carburization temperature as that of thoriated tungsten. The present invention can improve the processing performance of the material, reduce the wire breakage rate during the production and use of the material, and reduce the electronic work function of the material. The present invention can reduce the wire breakage rate and improve the yield rate to reduce the production and transportation costs, and can effectively increase the service life of the filament to make the service life reach and far exceed the service life of the existing thoriated tungsten filament.

[0404] The filament provided by the present invention can obtain an extremely high recrystallization temperature, and can still obtain extremely fine grains at the same carburization temperature as thoriated tungsten. The material has excellent shock resistance and can reduce the breakage and failure of the filament during production, transportation and use.

[0405] It should be noted that:

[0406] In this article, “~” is used to indicate a numerical range, and the range indicated by this expression includes two endpoint values;

[0407] In summary, the specific parameters or some common reagents or raw materials in the above embodiments are specific embodiments or preferred embodiments of the present invention, but are not intended to limit the present invention; those skilled in the art can make adaptive adjustments within the scope of the present invention. In addition, unless otherwise specified, the raw materials used may also be conventional commercial products in the art, or may be prepared by conventional methods in the art.

[0408] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0409] Although the terms such as the initial recrystallization temperature, the average size of oxides, etc. are used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A method for preparing tungsten alloy wire, characterized in that: The tungsten alloy wire comprises the following components: 0.0005-0.3 wt% carbon element, 0.25-2.6 wt% M element, 0.05-0.5 wt% oxygen element, the remainder being tungsten element and inevitable impurities, and the components do not contain thorium element; The M element is selected from one or more combinations of La, Y, Sc, Nd, Sm, Lu, Ce, Gd, Tb, Dy, Ho, Pr, Er, Tm, Yb, Eu, Hf, and Zr; The preparation process of the tungsten alloy wire includes the steps of doping powder making, powder pressing, sintering, and pressure processing in sequence; In the pressure processing step, the sintered tungsten alloy billet obtained after sintering is refined into an intermediate specification wire with a diameter of 1.5 to 3.5 mm; then the intermediate specification wire is subjected to oxidation annealing at (1200 to 1500)°C, and the annealing speed is (3 to 10) m / min; after oxidation annealing, the intermediate specification wire is further processed to the required wire diameter specification, so as to obtain tungsten alloy wire; Wherein, the initial recrystallization temperature of the tungsten alloy wire is 48%Fc-56%Fc, and / or the average size of the 80%Fc recrystallized grains is (1-15) μm.

2. The method for preparing tungsten alloy wire according to claim 1, characterized in that: The sintering step adopts a high temperature sintering method to obtain a tungsten alloy sintered billet; The heating curve of the high temperature sintering is: Raise the temperature from room temperature to A1 at a certain rate, and keep it at A1 for a certain period of time; Heat up from A1 to A2, the heating time is H3; keep warm at A2 for H4 hours; where A1 is (950-1250)°C, H3 is (1.5-2.5)h, A2 is (1300-1500)°C, H4 is (2.5-4.5); Raise the temperature from A2 to A3 at a certain rate, A3 is (1700~1900)℃; keep the temperature at A3 for a certain period of time; Heat up from A3 to A4 at a certain rate, A4 is (2050~2250)℃; keep warm at A4 for a certain time; It is obtained by natural cooling from A4.

3. The method for preparing tungsten alloy wire according to claim 2, characterized in that: The heating curve of the high temperature sintering is: From room temperature to A1, the heating time H1 is (5-8) h, and A1 is (950-1250) °C; Keep warm at A1 for H2 hours, H2 is (1~3); From A1 to A2, the heating time is H3, H3 is (1.5-2.5) h, A2 is (1300-1500) °C; Keep warm at A2 for H4 hours, H4 is (2.5~4.5); From A2 to A3, the heating time is H5, H5 is (1-3) h, A3 is (1700-1900) °C; Keep warm at A3 for H6 hours, H6 is (1~3); From A3 to A4, the heating time is H7, H7 is (1-3) h, A4 is (2050-2250) °C; Keep warm at A4 for H8 hours, H8 is (5-10); It is obtained by natural cooling from A4.

4. The method for preparing tungsten alloy wire according to any one of claims 2 to 3, characterized in that: The M element exists in the form of oxide, and the average size of the oxide particles in the tungsten alloy wire is (100-500) nm.

5. A tungsten alloy wire, characterized in that: The composition comprises the following components: 0.0005-0.3 wt% carbon element, 0.25-2.6 wt% M element, 0.05-0.5 wt% oxygen element, the balance being tungsten element and unavoidable impurities, and the composition does not contain thorium element; Wherein, the M element is selected from one or more combinations of La, Y, Sc, Nd, Sm, Lu, Ce, Gd, Tb, Dy, Ho, Pr, Er, Tm, Yb, Eu, Hf, and Zr; The initial recrystallization temperature of the tungsten alloy wire is 48%Fc-56%Fc, and / or the average size of its 80%Fc recrystallized grains is (1-15) μm; the average size of the oxide particles in the tungsten alloy wire is (100-500) nm.

6. The tungsten alloy wire according to claim 5, characterized in that: The M element exists in the form of an oxide, and the carbon element exists in the form of a carbide or a single carbon; The oxide of M is selected from one or more combinations of lanthanum oxide, yttrium oxide, scandium oxide, neodymium oxide, samarium oxide, lutetium oxide, cerium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, praseodymium oxide, erbium oxide, hafnium oxide, and zirconium oxide; The carbide is selected from one or more combinations of lanthanum carbide, zirconium carbide, yttrium carbide, hafnium carbide and tungsten carbide.

7. The tungsten alloy wire according to claim 5, characterized in that: The wire diameter is 800μm or less, and the number of flaw detection points is less than 5 / 100m; And / or, its components further include T element; the T element is a metal element, and the T is selected from at least one of K, Re, Mo, Fe, and Co; wherein the mass content of the Re is less than 1000 ppm.

8. A use of tungsten alloy wire, characterized in that: After the tungsten alloy wire is carbonized, it is used as a cathode alloy wire for a microwave heating device; Wherein, the tungsten alloy wire is the tungsten alloy wire as described in any one of claims 5-7, or the tungsten alloy wire is prepared by the preparation method as described in any one of claims 1-4.

9. A tungsten carbide alloy filament, characterized in that: It is obtained by carbonizing tungsten alloy wire; Wherein, the tungsten alloy wire is the tungsten alloy wire as described in any one of claims 5-7, or the tungsten alloy wire is prepared by the preparation method as described in any one of claims 1-4.

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