A method for preparing a high-performance porous titanium-based intermetallic compound filter

Abstract

The application provides a preparation method of a high-performance porous titanium-based intermetallic compound filter and relates to the technical field of filter preparation.The method comprises sequentially performing titanium raw material hydrogenation, micron-sized titanium hydride powder preparation, mixed powder preparation, mixed powder dehydrogenation alloying, micron-sized alloy powder preparation, cold isostatic forming mold preparation of the porous titanium-based intermetallic compound filter, titanium-based filter compact preparation and porous titanium-based intermetallic compound filter preparation.The application uses off-grade titanium as a matrix raw material, adds alloying elements such as aluminum and iron, combines the hydrogenation-dehydrogenation process with high-energy ball milling, and then realizes near forming of the porous titanium-based intermetallic compound filter through cold isostatic pressing and vacuum sintering.The prepared filter has high porosity, uniform pore size distribution and excellent corrosion resistance, can be used stably for a long time in a high-temperature and strong-corrosion environment, can realize efficient and high-precision purification of titanium tetrachloride, and is beneficial to industrial large-scale production and popularization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filter preparation, and particularly relates to a preparation method of a high-performance porous titanium-based intermetallic compound filter. BACKGROUND

[0002] At present, titanium tetrachloride is mainly produced by reducing chlorination of high-titanium slag, rutile and other raw materials. However, the titanium tetrachloride obtained by this method usually contains a large amount of solid impurity particles, which greatly reduces the quality of sponge titanium and titanium dioxide and adversely affects the performance of downstream products.

[0003] In order to ensure the stability of the subsequent deep processing process and the high purity of the final product, the titanium tetrachloride must be subjected to impurity removal treatment. In the past, due to the high volatility, high corrosiveness and strong reactivity of titanium tetrachloride, the effects of stainless steel and ceramic filters in actual use are not ideal. Titanium can provide good resistance in the production and purification filtration process of titanium tetrachloride due to its excellent corrosion resistance and high chemical stability. However, problems such as corrosion and poor filtration stability still occur during long-term operation, increasing the application cost.

[0004] Therefore, the preparation of a low-cost high-performance porous filter will be an important breakthrough direction for the development of titanium tetrachloride filtration technology.

[0005] Intermetallic compounds combine the properties of metals and ceramics, and can still guarantee excellent mechanical properties in extreme environments of high temperature and high corrosion. Intermetallic compound porous materials can also maintain stable pore structure at high temperatures. Therefore, titanium-based intermetallic compounds have extremely high specific elastic modulus, specific weight, excellent high-temperature performance, good oxidation resistance and corrosion resistance, and are widely used in aerospace, national defense equipment, chemical industry and other fields, and perform well in filtration applications, and are considered as ideal materials for high-performance filters.

[0006] In 2023, the production of sponge titanium in China was 218,000 tons. However, due to various factors in the production process, the quality, morphology and particle size of part of the sponge titanium cannot meet the national sponge titanium quality standard, and such sponge titanium is called off-grade titanium. The yield of off-grade titanium accounts for more than 5% of the total production of sponge titanium. At present, off-grade titanium is mainly used as raw material or additive in casting, powder metallurgy and other fields, and the actual value of off-grade titanium cannot be fully utilized.

[0007] Therefore, there is an urgent need for a low-cost, high-yield preparation method for using off-grade titanium, sponge titanium or titanium waste as raw material or additive for filter, which can improve the comprehensive performance of the filter such as high-temperature strength and corrosion resistance.

[0008] And the Chinese patent CN117123777A discloses a method for preparing porous titanium, which is obtained by mixing metal titanium powder with alkaline earth metal powder, then pressing into shape, followed by sintering, vacuum distillation, washing and drying. Obviously, the main purpose is to avoid the influence of oxidation on performance, but calcium powder needs to be added to the raw material, and volatile condensed metal calcium is removed by vacuum distillation, and then hydrochloric acid is needed to remove calcium oxide. The process is complex, the removal of calcium element is not complete, and the pore distribution is not uniform.

[0009] The Chinese patent CN107675021A discloses an intermetallic compound titanium-silicon-molybdenum porous material and a preparation method thereof, which needs to add silicon powder and molybdenum powder in titanium powder, mix and ball mill, then press the compact, and then vacuum sinter to obtain a porous material. Obviously, the porosity of the prepared material cannot reach 60%, and the mold is not designed and prepared. The porous structure is prepared by removing the foaming agent tosylhydrazide to decompose and form, which has a large loss of organic solvent, and the alloying process is carried out in sintering, and the alloying effect is not good.

[0010] The Chinese patent CN105603239A discloses a method for preparing porous Ti3Al intermetallic compound by Al alloy pressureless infiltration of TiH2 powder, which is prepared by weighing Al-12Si alloy block and TiH2 powder, preparing porous TiH2 preform, low-temperature pressureless infiltration pore forming and high-temperature heat treatment. The low-temperature pressureless infiltration pore forming needs to decompose TiH2 powder to form pores, and then it is not treated by hydrogen removal, so the hydrogen content of the prepared porous Ti3Al intermetallic compound is not low. SUMMARY

[0011] In order to solve the problems of short service life of titanium filter, insufficient filtering precision, complex process, incomplete removal of calcium element, uneven pore distribution, poor high temperature resistance and corrosion resistance, high preparation cost, poor filtering efficiency, large loss of organic solvent, poor alloying effect and high hydrogen content in the prior art, the present application provides a preparation method of a high-performance porous titanium-based intermetallic compound filter which can solve the above-mentioned problems. The technical solution is as follows:

[0012] A preparation method of a high-performance porous titanium-based intermetallic compound filter, the preparation method of the high-performance porous titanium-based intermetallic compound filter comprising the following steps:

[0013] S1, titanium raw material hydrogenation: hydrogenating the titanium raw material block by using a hydrogenation furnace to obtain a brittle hydrogenated titanium block;

[0014] S2, micron-sized hydrogenated titanium powder preparation: placing the brittle hydrogenated titanium block of S1 into a ball mill tank filled with high-purity argon protection for high-energy ball milling to obtain micron-sized hydrogenated titanium powder;

[0015] S3, mixed powder preparation: the S2 micron-sized titanium hydride powder is mixed with aluminum powder or iron powder in a mixer protected by high-purity argon to obtain a mixed powder with uniform mixing;

[0016] S4, mixed powder dehydrogenation alloying: the S3 mixed powder with uniform mixing is placed in a vacuum furnace for dehydrogenation treatment, and after the dehydrogenation is completed, alloy powder particles are obtained;

[0017] S5, micron-sized alloy powder preparation: the S4 alloy powder particles are placed in a ball mill tank filled with argon protection, a pore former is added, and high-energy ball milling is performed to obtain micron-sized alloy powder;

[0018] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: a polyurethane or silicone rubber sleeve is made into a tubular or square tubular shape, a stainless steel mandrel is arranged in the middle of the sleeve, the mandrel is fixed by a polyurethane or silicone rubber plug matched with the upper and lower ports of the sleeve, a porous stainless steel liner is matched with the outer polyurethane or silicone rubber sleeve, the length of the liner is the same as that of the sleeve, and the diameter of the liner is larger than that of the sleeve, and the cold isostatic forming mold is composed of the sleeve, the mandrel, the plug and the liner;

[0019] S7, titanium-based filter compact preparation: the S5 micron-sized alloy powder is loaded into the tubular or square tubular sleeve in S6, and sealed and combined; then the powder-loaded forming mold is placed in a cold isostatic pressing machine for cold isostatic pressing forming, demolding and taking out to obtain a titanium-based filter compact;

[0020] S8, porous titanium-based intermetallic compound filter preparation: the S7 titanium-based filter compact is placed in a vacuum sintering furnace, vacuumized and heated for sintering to obtain a high-performance porous titanium-based intermetallic compound filter.

[0021] Optionally, the temperature of the hydrogenation treatment in S1 is 300-600°C, the holding time is 1-4h, the hydrogen content in the easily broken titanium hydride block is 2-3.5wt.%, and the titanium raw material block is out-of-specification titanium, sponge titanium or other titanium waste with no oil stains on the surface.

[0022] Optionally, in S2, the ball-to-material ratio of high-energy ball milling is 5:1-10:1, the ball milling speed is 300-600rpm, the milling balls are stainless steel balls with a diameter of 6-10mm, the ball milling time is 2-4h, the particle size of the micron-sized titanium hydride powder is 150-500μm, and the shape is irregular block.

[0023] Optionally, in S3, the particle size of the aluminum powder or iron powder is 150-500μm, the aluminum powder is gas-atomized aluminum powder, the iron powder is carbonyl iron powder or reduced iron powder, the atomic ratio of each element in the powder is Ti:Al=(1-X):X, X=0.35-0.66, or Ti:Fe=(1-Y):Y, Y=0.5-0.6.

[0024] Optionally, the dehydrogenation temperature in S4 is 600-900 DEG C, the dehydrogenation time is 1-4 h, the vacuum degree in the vacuum furnace is 10 -2 -10 Pa, the hydrogen content of the alloy powder particles is ≤0.1 wt.%.

[0025] Optionally, the pore-forming agent in S5 is NaCl, KCl or CaCl2 salt, and the addition amount is 5-10 wt.% of the alloy powder particles; the ball-to-material ratio of high-energy ball milling is 2:1-10:1, the ball milling speed is 300-600 rpm, the ball is a stainless steel ball with a diameter of 6-10 mm, the ball milling time is 2-5 h, the particle size of the micron-sized alloy powder is 75-200 μm, and the hydrogen content is ≤0.1 wt.%.

[0026] Optionally, the total length of the soft sleeve in S6 is 5-200 cm, the thickness is 5-25 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a zigzag or corrugated engagement, the upper end length is 1 / 2-3 / 4 of the total length of the sleeve; the stainless steel bushing is a left-right split mold structure and is fixed by a throat clamp or a buckle, the bushing thickness is 1-3 mm; the taper of the core rod is 1-3 DEG, and the diameter of the bushing is 2-8 mm larger than the diameter of the soft sleeve; the hole diameter of the porous stainless steel bushing is 3-20 mm, and the hole area is 50-80% of the outer surface area of the bushing.

[0027] Optionally, the pressing pressure of the cold isostatic pressing in S7 is 80-200 MPa, the pressure holding time is 60 s-240 s, the shape of the titanium-based filter compact is tubular or square tubular, the wall thickness is 10-20 mm, and the porosity is 30-55%.

[0028] Optionally, the sintering temperature in S8 is 1000-1200 DEG C, the vacuum degree is 1-10 -2 Pa, and the sintering time is 1-4 h.

[0029] Optionally, the porosity of the porous titanium-based intermetallic compound filter in S8 is 30-60%, the pore size is 10-100 μm, the hydrogen content is ≤0.015 wt.%, and the compressive strength is ≥50 MPa.

[0030] The technical principle of the application is as follows:

[0031] The raw material titanium of the application is not limited to off-grade titanium, sponge titanium or other surface oil-free titanium waste such as titanium chips and scrap materials, which can be used as the preparation raw material.

[0032] In the preparation process of the application, the hydrogen content of the titanium hydride block is ≥2wt.% and ≤3.5wt.%, which is obtained through a large number of experimental verification and optimization, and cannot be obtained by conventional experiments. The lower limit of hydrogen content 2wt.% is to ensure that the titanium hydride block is easier to break during high-energy ball milling, and the upper limit of hydrogen content 3.5wt.% is to reduce the production cost and improve the production efficiency.

[0033] In the preparation process of the application, the titanium hydride powder will undergo dehydrogenation and self-propagating reaction simultaneously with aluminum powder or iron powder during the dehydrogenation process. On the one hand, H in the titanium hydride escapes during the dehydrogenation process, obtaining Ti powder, and diffusing and alloying with Al and Fe; on the other hand, there are special requirements for the added Al and Fe components, Ti:Al=(1-X):X (X=0.35-0.66) or Ti:Fe=(1-Y):Y (Y=0.5-0.66), which makes the self-propagating reaction occur during the diffusion process of Ti and Al or Fe during high-temperature dehydrogenation, generating brittle TiAl or TiFe intermetallic compound particles with uniform composition. Subsequently, high-energy crushing is carried out to obtain TiAl or TiFe intermetallic compound powder raw materials with target particle size.

[0034] The soft sleeve structure, core rod taper design, core rod fixing method, and stainless steel bushing structure designed in the application are obtained through a large number of experimental optimization and verification, combined with the characteristics of titanium alloy powder, forming problems, demolding difficulty, filter structure, and quality, and matched with parameters such as deformation control, shrinkage, porosity, and coating thickness in the cold isothermal forming process of titanium alloy filter, which cannot be obtained by conventional experimental operation.

[0035] In order to ensure the integrity and forming quality of the directly formed filter structure, the soft sleeve structure is designed, the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened, through serrated or corrugated engagement, the upper end length is 1 / 2-3 / 4 of the total length of the sleeve, which can ensure that the formed filter green body is easy to demold, the structure of the green body is complete, and there is no problem such as damage, angle missing, and crack. The lower end cannot be opened, which ensures the accuracy of the mold closing, and can avoid problems such as inaccurate mold positioning and poor surface quality of the green body caused by too long sleeve.

[0036] In order to directly form the filter of the hollow structure, the intermediate core rod structure is designed, the core rod is fixed through the plug matched with the upper and lower ports of the soft sleeve, the core rod is prevented from moving during the powder loading process, the powder loading is uniform, the wall thickness of the blank is consistent, the straightness of the hollow structure of the filter is ensured, and in order to facilitate demolding and not damage the internal structure of the blank, the core rod is designed to have a taper of 1-3 degrees, after the blank is formed, the taper design enables the core rod to be directly demolded, the operation is simple and convenient, the internal structure of the blank is complete, and there is no defect. The taper angle is obtained through a large number of test verifications, and if the taper angle is too large, stress unevenness cannot be formed or the blank is cracked.

[0037] In order to ensure the quality of the outer surface of the filter blank, a porous stainless steel bushing structure is designed, the hole diameter of the bushing is 3-20 mm, the hole area is 50-80% of the outer surface area of the bushing, and the thickness is 1-3 mm, so that the shape structure of the soft sleeve is ensured, the high and long filter blank structure is not deformed, and problems such as bending and warping do not exist, the meshing stability of the upper opening soft sleeve is ensured, and defects such as concave-convex at the opening gap are avoided. At the same time, the porous structure design does not affect the transmission of liquid pressure to the soft sleeve, and ensures the consistency of the blank density. In addition, the bushing left and right parting structure makes the demolding operation simple.

[0038] In the preparation process of the application, the dehydrogenation reaction and the self-propagating reaction occur simultaneously when the mixed powder is dehydrogenated, a remarkable advantage of the self-propagating reaction is that the reaction itself releases a large amount of heat, and the reaction is usually completed in a very short time, so that the required compound can be rapidly generated, for example, in the preparation process of titanium-aluminum intermetallic compounds, Ti3Al and TiAl high-temperature phases can be efficiently generated to improve the mechanical properties and corrosion resistance of the material under high-temperature conditions. The extremely high reaction rate enables the powder particles to rapidly fuse and phase change, thereby ensuring the uniformity of the organization structure and composition.

[0039] The aluminum powder used in the application is gas-atomized aluminum powder, the iron powder is carbonyl iron powder or reduced iron powder, and the atomic ratio of each element in the powder is Ti:Al=(1-X):X (X=0.35-0.66) or Ti:Fe=(1-Y):Y (Y=0.5-0.66). The design of the atomic ratio of titanium and aluminum Ti:Al=(1-X):X (X=0.35-0.66) enables the TiAl intermetallic compound to have a2-Ti3Al and gamma-TiAl intermediate phase. The a2-Ti3Al phase has excellent corrosion resistance, and the gamma-TiAl phase has low density and high-temperature structural stability, so that the filter prepared by the application can still maintain a stable pore structure under high-temperature and strong corrosion environment; the design of the atomic ratio of titanium and iron Ti:Fe=(1-X):X (X=0.5-0.66) ensures that high-performance TiFe intermetallic compounds are generated, which have excellent physical and chemical properties and high-temperature and corrosion resistance.

[0040] The aluminum powder and the iron powder used in the preparation process of the application are coarse powder with a particle size of 150-500 mu m, and the coarse powder has a smaller surface area and a lower oxygen content than the fine powder under the same mass. Therefore, coarse powder raw materials are used in the preparation process to ensure a lower oxygen content of the titanium-based powder system, so as to avoid the influence of high oxygen content on the quality of the filter and reduce the performance of the filter.

[0041] In the preparation process of the application, the hydrogen content of the titanium-based alloy powder is ≤0.1wt.%, and when the hydrogen content is too high, the titanium-based filter blank is destroyed in the subsequent sintering process due to too large a dehydrogenation amount, and even brittle fracture occurs, and the hydrogen content of the titanium-based intermetallic compound filter after sintering is ≤0.015wt.%, therefore, the hydrogen content in each process is limited, which is obtained through a large number of experiments and cannot be obtained through conventional empirical calculation.

[0042] Compared with the prior art, the above technical scheme has at least the following beneficial effects:

[0043] The above scheme provides a preparation method of a high-performance porous titanium-based intermetallic compound filter, which can solve the problems of short service life, insufficient filtering precision, complex process flow, incomplete removal of calcium elements, uneven pore distribution, poor high-temperature resistance and corrosion resistance, high preparation cost, poor filtering efficiency, large loss of organic solvents, poor alloying effect, and high hydrogen content of the titanium filter using titanium tetrachloride in the prior art.

[0044] The raw material cost of the application is low, the preparation process is simple, the flow is short, the industrial applicability is strong, and the titanium resources are recycled and reused, realizing the sustainable development of titanium resources. The filter prepared by the application is not only applied to the field of titanium tetrachloride filtration, but also applicable to the filtration of other industrial products, especially the filtration of products in extreme environments, and has good technical universality.

[0045] In the preparation process of the application, the titanium hydride powder will undergo dehydrogenation and self-propagating reaction simultaneously with the aluminum powder or the iron powder in the dehydrogenation process. This process design avoids the self-propagating reaction of Ti, Al or Fe in the subsequent sintering process, and avoids the problems of destroyed filter structure, low forming quality, etc. caused by the occurrence of violent self-propagating reaction of the formed filter blank in the sintering process.

[0046] The soft sleeve structure is designed, the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened, and the upper end opening length is 1 / 2-3 / 4 of the total length of the sleeve, which is obtained through test optimization, which can not only ensure that the blank demolding is simple and convenient, but also ensure the accuracy of the mold closing.

[0047] The intermediate core rod structure design and fixing mode in the application not only ensures that the core rod does not move during powder loading, so that the powder is uniformly loaded and the wall thickness of the blank is uniform, but also ensures the straightness of the hollow structure of the filter; the 1-3° taper design of the core rod makes demolding convenient and does not damage the internal structure of the blank, and the demolding operation is simple and convenient, the internal structure of the blank is complete, and there is no defect.

[0048] The porous stainless steel liner structure design of the application not only ensures the quality of the outer surface of the filter blank, but also ensures the shape structure of the soft sleeve, so that the high and long filter blank structure is not deformed, and there is no problem such as bending and warping; at the same time, the engagement stability of the open soft sleeve at the upper end is ensured, and defects such as concave-convex at the opening gap are avoided. In addition, the porous structure design does not affect the transmission of liquid pressure to the soft sleeve, ensuring the consistency of the blank density. The left and right split mold structure of the liner makes the demolding operation simple.

[0049] In the application, titanium hydride blocks which are easy to break are used as raw materials, although the cost of raw materials and subsequent crushing and grinding is low, but the hydrogen content in the mixed powder is high, which affects the normal use and service life of the filter, and hydrogen needs to be removed before pressing and forming, so the hydrogen content in the prepared mixed powder and the compact and the filter needs to be monitored and controlled at any time, so that the hydrogen content in the final filter is controlled to be ≤0.015wt.%.

[0050] The application adopts titanium raw material blocks, low-priced raw materials such as aluminum and iron, hydrogenation and dehydrogenation, mold design and preparation, and cold isostatic pressing process, which can realize near forming of the filter, and the material utilization rate can reach more than 98%, thereby reducing the preparation cost of the filter. In particular, by designing the specifications and shapes of the cold isostatic pressing sleeve, filters required for different application scenarios can be prepared.

[0051] The filter preparation technology disclosed in the application adopts a low-cost raw material combined with a short process and a near-net-shape powder metallurgy process, can meet the filtering demand in extreme environments, is not only suitable for filtering titanium tetrachloride, but also suitable for filtering in other fields, has good process economy, and is suitable for industrial production.

[0052] In summary, compared with other traditional methods, the method of the application uses off-gauge titanium as a base raw material, adds alloying elements such as aluminum and iron, realizes near-net-shape forming of the porous titanium-based intermetallic compound filter through a hydrogenation and dehydrogenation process combined with high-energy ball milling, and then through cold isostatic pressing and vacuum sintering; the prepared filter has high porosity, uniform pore size distribution and excellent corrosion resistance, can be used stably for a long time in a high-temperature and strong-corrosion environment, can realize efficient and high-precision purification of titanium tetrachloride, and is beneficial to industrial large-scale production and promotion. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

[0054] Figure 1 is a process flow chart of a preparation method of a high-performance porous titanium-based intermetallic compound filter of the present application;

[0055] Figure 2 is a structure diagram of a soft sleeve and a bushing involved in the preparation method of the high-performance porous titanium-based intermetallic compound filter of the present application, wherein, Fig. (a) is a front view of the bushing, Fig. (b) is a front view of the soft sleeve, and Fig. (c) is an effect diagram of the soft sleeve after being opened. DETAILED DESCRIPTION

[0056] The technical solutions in the present application will be described below with reference to the drawings.

[0057] In the embodiments of the present application, the words such as "example", "for example" are used to represent as an example, illustration or description. Any embodiment or design scheme described as "example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. In fact, the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present application, the meaning expressed by "and / or" can be both, or can be one of the two.

[0058] In the embodiments of the present application, "image" and "picture" can be used interchangeably at times. It should be pointed out that when the distinction is not emphasized, the meanings expressed are consistent.

[0059] In the embodiments of the present application, sometimes the subscript such as W1 can be written in the form of non-subscript such as W1. When the distinction is not emphasized, the meanings expressed are consistent.

[0060] In order to make the technical problems, technical solutions and advantages to be solved by the present application more clear, the following will be described in detail with reference to the drawings and specific embodiments.

[0061] A preparation method of a high-performance porous titanium-based intermetallic compound filter, the preparation method of the high-performance porous titanium-based intermetallic compound filter combines Figure 1 the following steps:

[0062] S1, titanium raw material hydrogenation: hydrogenation furnace is used to hydrogenate titanium raw material blocks to obtain easily broken hydrogenated titanium blocks;

[0063] S2, Preparation of micrometer-sized titanium hydride powder: Put the easily broken titanium hydride block of S1 into a ball mill tank filled with high-purity argon protection to carry out high-energy ball milling, to obtain micrometer-sized titanium hydride powder;

[0064] S3, Preparation of mixed powder: Mix the micrometer-sized titanium hydride powder of S2 with aluminum powder or iron powder in a mixer protected by high-purity argon to obtain mixed powder with uniform mixing;

[0065] S4, Dehydrogenation alloying of mixed powder: Put the mixed powder of S3 with uniform mixing into a vacuum furnace for dehydrogenation treatment, and obtain alloy powder particles after dehydrogenation;

[0066] S5, Preparation of micrometer-sized alloy powder: Put the alloy powder particles of S4 into a ball mill tank filled with argon protection, add pore-forming agent, and carry out high-energy ball milling to obtain micrometer-sized alloy powder;

[0067] S6, Preparation of cold isostatic forming mold for porous titanium-based intermetallic compound filter: Use polyurethane or silicone to make a tubular or square tubular soft sleeve with a stainless steel mandrel in the middle. The mandrel is fixed by a polyurethane or silicone plug that matches the upper and lower ports of the soft sleeve. The polyurethane or silicone soft sleeve is matched with a porous stainless steel liner. The length of the liner is the same as that of the soft sleeve, and the diameter of the liner is larger than that of the soft sleeve. The cold isostatic forming mold is composed of the soft sleeve, the mandrel, the plug, and the liner. The specific structure of the soft sleeve and the liner is shown in Figure 2 ;

[0068] S7, Preparation of titanium-based filter compact: Put the micrometer-sized alloy powder of S5 into the tubular or square tubular soft sleeve of S6, and seal and combine the powder. Then put the formed mold with the powder into a cold isostatic pressing machine for cold isostatic pressing, demold, and obtain a titanium-based filter compact;

[0069] S8, Preparation of porous titanium-based intermetallic compound filter: Put the titanium-based filter compact of S7 into a vacuum sintering furnace, heat and sinter after vacuumizing, and obtain a high-performance porous titanium-based intermetallic compound filter.

[0070] In particular, the temperature of the hydrogenation treatment in S1 is 300-600℃, the holding time is 1-4h, the hydrogen content in the easily broken titanium hydride block is 2-3.5wt.%, and the titanium raw material block is out-of-specification titanium, sponge titanium or other titanium waste with no oil stains on the surface.

[0071] In particular, the ball-to-material ratio of high-energy ball milling in S2 is 5:1-10:1, the ball milling speed is 300-600rpm, the milling balls are stainless steel with a diameter of 6-10mm, the ball milling time is 2-4h, the particle size of the micrometer-sized titanium hydride powder is 150-500μm, and the shape is irregular block.

[0072] In particular, the particle size of the aluminum powder or iron powder in S3 is 150-500 μm, wherein the aluminum powder is gas atomized aluminum powder, and the iron powder is carbonyl iron powder or reduced iron powder; the atomic ratio of each element in the powder is Ti:Al=(1-X):X, X=0.35-0.66, or Ti:Fe=(1-Y):Y, Y=0.5-0.6.

[0073] In particular, the dehydrogenation temperature in S4 is 600-900 °C, the dehydrogenation time is 1-4 h, and the vacuum degree in the vacuum furnace is 10 -2 -10 Pa, and the hydrogen content of the alloy powder particles is ≤0.1 wt.%.

[0074] In particular, the pore-forming agent in S5 is NaCl, KCl or CaCl2 salt, and the addition amount is 5-10 wt.% of the alloy powder particles; the ball-to-powder ratio of high-energy ball milling is 2:1-10:1, the ball milling speed is 300-600 rpm, the milling balls are stainless steel balls with a diameter of 6-10 mm, the ball milling time is 2-5 h, the particle size of the micron-sized alloy powder is 75-200 μm, and the hydrogen content is ≤0.1 wt.%.

[0075] In particular, the total length of the soft sleeve in S6 is 5-200 cm, the thickness is 5-25 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened by a zigzag or corrugated engagement, and the length of the upper end is 1 / 2-3 / 4 of the total length of the sleeve; the stainless steel liner is a left-right split mold structure, is fixed by a throat clamp or a buckle, and has a thickness of 1-3 mm; the taper of the core rod is 1-3°, and the diameter of the liner is 2-8 mm larger than the diameter of the soft sleeve; the hole diameter of the porous stainless steel liner is 3-20 mm, and the hole area is 50-80% of the outer surface area of the liner.

[0076] In particular, the pressing pressure of the cold isostatic pressing in S7 is 80-200 MPa, the pressure holding time is 60 s-240 s, the shape of the titanium-based filter compact is tubular or square tubular, the wall thickness is 10-20 mm, and the porosity is 30-55%.

[0077] In particular, the sintering temperature of the vacuum sintering in S8 is 1000-1200 °C, the vacuum degree is 1-10 -2 Pa, and the sintering time is 1-4 h.

[0078] In particular, the porosity of the porous titanium-based intermetallic compound filter in S8 is 30-60%, the pore size is 10-100 μm, the hydrogen content is ≤0.015 wt.%, and the compressive strength is ≥50 MPa.

[0079] Example 1

[0080] A method for preparing a high-performance porous titanium-based intermetallic compound filter, the method comprising the following steps:

[0081] S1, titanium raw material hydrogenation: using a hydrogenation furnace to hydrogenate 20 kg of off-spec titanium blocks, the hydrogenation temperature is 350 DEG C, the hydrogenation treatment time is 2 h, the hydrogen content in the easily broken hydrogenated titanium blocks is 2.8 wt.%, and easily broken hydrogenated titanium blocks are obtained;

[0082] S2, micron-sized hydrogenated titanium powder preparation: placing the S1 easily broken hydrogenated titanium blocks into a ball mill tank filled with high-purity argon protection for high-energy ball milling, the ball-to-material ratio of high-energy ball milling is 10:1, the ball milling speed is 300 rpm, the grinding ball is a stainless steel component with a size of 6 mm, the ball milling time is 2 h, and micron-sized hydrogenated titanium powder is obtained; the particle size of the micron-sized hydrogenated titanium powder is 200 μm, and the shape is irregular blocky;

[0083] S3, mixed powder preparation: mixing the S2 micron-sized hydrogenated titanium powder and 6.1 kg of aluminum powder using a high-purity argon protection mixer, the particle size of the aluminum powder is 200 μm, wherein the aluminum powder is an air-atomized aluminum powder; the atomic ratio of each element in the powder is Ti:Al=0.65:0.35, and a mixed powder with uniform mixing is obtained;

[0084] S4, mixed powder dehydrogenation alloying: placing the S3 mixed powder with uniform mixing into a vacuum furnace for dehydrogenation treatment, the dehydrogenation temperature is 800 DEG C, the dehydrogenation time is 4 h, the vacuum degree in the vacuum furnace is 10 -2 Pa, and alloy powder particles are obtained after dehydrogenation; the hydrogen content of the alloy powder particles is 0.1 wt.%;

[0085] S5, micron-sized alloy powder preparation: placing the S4 alloy powder particles into a ball mill tank filled with argon protection, adding a pore-forming agent, the pore-forming agent is NaCl, and the addition amount is 5 wt.% of the alloy powder particles; high-energy ball milling is performed, the ball-to-material ratio of high-energy ball milling is 5:1, the ball milling speed is 300 rpm, the grinding ball is a stainless steel component with a size of 6 mm, the ball milling time is 4 h, and micron-sized alloy powder is obtained; the particle size of the micron-sized alloy powder is 100 μm, and the hydrogen content is 0.1 wt.%;

[0086] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: using polyurethane to make a tubular soft sleeve, a stainless steel mandrel is arranged in the middle of the soft sleeve, the mandrel is fixed by a polyurethane plug that matches the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched outside the polyurethane soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, and the cold isostatic forming mold is composed of the soft sleeve, the mandrel, the plug and the liner;

[0087] The soft sleeve has a total length of 20 cm, an inner diameter of 60 mm, and a thickness of 5 mm, and has a structure in which the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a sawtooth-shaped engagement, and the upper end has a length of 1 / 2 of the total length of the sleeve; the stainless steel liner has a left-right split mold structure and is fixed by a buckle; the core rod has a diameter of 38 mm, a core rod taper of 2°, a liner length of 20 cm, a liner diameter of 72 mm, and a liner hole diameter of 3 mm, and a hole area of 50% of the total area of the liner;

[0088] S7, green compact preparation of titanium-based filter: the micron-sized alloy powder of S5 is loaded into the tubular soft sleeve in S6, and sealed and combined; then the powder-loaded forming mold is placed into a cold isostatic pressing machine for cold isostatic pressing, the pressing pressure of the cold isostatic pressing is 120 MPa, the pressure holding time is 120 s, the mold is demolded and taken out, and a titanium-based filter green compact is obtained; the titanium-based filter green compact has a tubular shape, a wall thickness of 10 mm, and a porosity of 40%;

[0089] S8, preparation of porous titanium-based intermetallic compound filter: the titanium-based filter green compact of S7 is placed into a vacuum sintering furnace, vacuumized, and then heated and sintered, the temperature of the vacuum sintering is 1200℃, the vacuum degree is 10 -2 Pa, the sintering time is 2 h, and a high-performance porous titanium-based intermetallic compound filter is obtained.

[0090] The porosity of the porous titanium-based intermetallic compound filter prepared in this embodiment is 38%, the pore size is 100 μm, the hydrogen content is 0.01 wt.%, and the compressive strength is 50 MPa.

[0091] Embodiment 2

[0092] A preparation method of a high-performance porous titanium-based intermetallic compound filter, the preparation method of the high-performance porous titanium-based intermetallic compound filter comprising the following steps:

[0093] S1, titanium raw material hydrogenation: 10 kg of titanium turnings with no oil stains on the surface are subjected to hydrogenation treatment by using a hydrogenation furnace, the hydrogenation treatment temperature is 350℃, hydrogen is introduced for 2 h, the hydrogen content in the broken hydrogenated titanium block is 3.3 wt.%, and a broken hydrogenated titanium block is obtained;

[0094] S2, preparation of micron-sized hydrogenated titanium powder: the broken hydrogenated titanium block of S1 is placed into a ball mill pot filled with high-purity argon protection for high-energy ball milling, the ball-to-material ratio of the high-energy ball milling is 8:1, the ball milling speed is 400 rpm, the size of the stainless steel grinding ball is 6 mm, and the ball milling time is 4 h, and micron-sized hydrogenated titanium powder is obtained; the particle size of the micron-sized hydrogenated titanium powder is 400 μm, and the shape is irregular blocky;

[0095] S3, mixed powder preparation: the S2 micron titanium hydride powder is mixed with 12 kg of iron powder in a mixer protected by high-purity argon, the particle size of the iron powder is 400 μm, the iron powder is carbonyl iron powder, the atomic ratio of each element in the powder is Ti:Fe = 1:1, and a mixed powder with uniform mixing is obtained;

[0096] S4, mixed powder dehydrogenation alloying: the mixed powder with uniform mixing of S3 is placed in a vacuum furnace for dehydrogenation treatment, the dehydrogenation temperature of the dehydrogenation treatment is 850°C, the dehydrogenation time is 3 h, the vacuum degree in the vacuum furnace is 10 -2 Pa, and the alloy powder particles are obtained after the dehydrogenation is completed; the hydrogen content of the alloy powder particles is 0.09wt.%;

[0097] S5, micron-sized alloy powder preparation: the S4 alloy powder particles are placed in a ball mill tank filled with argon protection, a pore former is added, the pore former is KCl, the addition amount is 10wt.% of the alloy powder particles; high-energy ball milling is carried out, the ball-to-material ratio of the high-energy ball milling is 10:1, the ball milling speed is 400 rpm, the size of the stainless steel milling ball is 8 mm, the ball milling time is 4 h, and micron-sized alloy powder is obtained; the particle size of the micron-sized alloy powder is 150 μm, and the hydrogen content is ≤0.09wt.%;

[0098] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: a polyurethane tubular soft sleeve is used, a stainless steel core rod is arranged in the middle of the soft sleeve, the core rod is fixed by a polyurethane plug matched with the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched outside the polyurethane soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, and the cold isostatic forming mold is composed of the soft sleeve, the core rod, the plug and the liner;

[0099] The total length of the soft sleeve is 100 cm, the inner diameter is 80 mm, the thickness is 15 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a zigzag engagement, the length of the upper end is 1 / 2 of the total length of the sleeve; the stainless steel liner is a left-right split mold structure and is fixed by a buckle; the diameter of the core rod is 58 mm, the taper of the core rod is 2°, the length of the liner is 100 cm, the diameter of the liner is 115 mm, the hole diameter of the liner is 5 mm, and the hole area is 60% of the total area of the liner;

[0100] S7, titanium-based filter green compact preparation: the S5 micron-sized alloy powder is loaded into the tubular soft sleeve in S6, and a sealed combination treatment is performed; then the powder-loaded forming mold is placed in a cold isostatic pressing machine for cold isostatic pressing forming, the pressing pressure of the cold isostatic pressing forming is 150 MPa, the pressure holding time is 90 s, the mold is removed, and a titanium-based filter green compact is obtained; the titanium-based filter green compact has a tubular shape, a wall thickness of 10 mm, and a porosity of 45%;

[0101] S8, porous titanium-based intermetallic compound filter preparation: the S7 titanium-based filter compact is put into a vacuum sintering furnace, and sintered after vacuumizing, the temperature of vacuum sintering is 1150℃, the vacuum degree is 10 -2 Pa, the sintering time is 4h, and a high-performance porous titanium-based intermetallic compound filter is obtained.

[0102] The porosity of the porous titanium-based intermetallic compound filter prepared in the embodiment is 40%, the pore size is 80μm, the hydrogen content is 0.011wt.%, and the compressive strength is 60MPa.

[0103] Embodiment 3

[0104] A method for preparing a high-performance porous titanium-based intermetallic compound filter, the method comprising the following steps:

[0105] S1, titanium raw material hydrogenation: 50kg of sponge titanium blocks are subjected to hydrogenation treatment by using a hydrogenation furnace, the hydrogenation treatment temperature is 380℃, hydrogen is introduced for 4h, the hydrogen content in the easily broken hydrogenated titanium blocks is 3.3wt.%, and easily broken hydrogenated titanium blocks are obtained;

[0106] S2, micron-sized hydrogenated titanium powder preparation: the S1 easily broken hydrogenated titanium blocks are put into a ball mill tank filled with high-purity argon protection for high-energy ball milling, the ball-to-material ratio of high-energy ball milling is 8:1, the ball milling speed is 500rpm, the size of the stainless steel milling ball is 10mm, the ball milling time is 2h, and micron-sized hydrogenated titanium powder is obtained; the particle size of the micron-sized hydrogenated titanium powder is 300μm, and the shape is irregular block;

[0107] S3, mixed powder preparation: the S2 micron-sized hydrogenated titanium powder and aluminum powder are mixed by using a mixer with high-purity argon protection, the particle size of the aluminum powder is 300μm, and the aluminum powder is gas-atomized aluminum powder; the atomic ratio of each element in the powder is Ti:Al=1:1, and uniformly mixed powder is obtained;

[0108] S4, mixed powder dehydrogenation alloying: the S3 uniformly mixed powder is put into a vacuum furnace for dehydrogenation treatment, the dehydrogenation temperature of dehydrogenation treatment is 900℃, the dehydrogenation time is 4h, and the vacuum degree in the vacuum furnace is 10 -2 Pa, and alloy powder particles are obtained after dehydrogenation; the hydrogen content of the alloy powder particles is 0.09wt.%;

[0109] S5, micron-sized alloy powder preparation: put the S4 alloy powder particles into a ball mill tank filled with argon protection, add a pore-forming agent, the pore-forming agent is CaCl2, the addition amount is 6wt.% of the alloy powder particles; carry out high-energy ball milling mixing, the ball-to-material ratio of high-energy ball milling is 5:1, the ball milling speed is 500 rpm, the milling balls are stainless steel balls with a size of 10 mm, the ball milling time is 4 h, to obtain micron-sized alloy powder; the particle size of the micron-sized alloy powder is 100 μm, and the hydrogen content is 0.09wt.%;

[0110] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: a polyurethane is used to make a square tube-shaped soft sleeve, a stainless steel core rod is arranged in the middle of the soft sleeve, the core rod is fixed by a polyurethane plug matched with the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched outside the polyurethane soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, and the cold isostatic forming mold is formed by the soft sleeve, the core rod, the plug and the liner;

[0111] Wherein, the total length of the soft sleeve is 50 cm, the inner edge length is 50 mm, the thickness is 10 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a zigzag engagement, and the length of the upper end is 3 / 4 of the total length of the sleeve; the stainless steel liner is a left-right split mold structure and is fixed by a throat clamp; the edge length of the core rod is 18 mm, the taper of the core rod is 1°, the length of the liner is 50 cm, the diameter of the liner is 52 mm, the hole diameter of the liner is 10 mm, and the hole area is 60% of the total area of the liner;

[0112] S7, titanium-based filter green compact preparation: the S5 micron-sized alloy powder is loaded into the tubular soft sleeve in S6, and sealed and combined; then the powder-loaded forming mold is placed into a cold isostatic pressing machine for cold isostatic pressing forming, the pressing pressure of the cold isostatic pressing forming is 150 MPa, the pressure holding time is 100 s, the mold is taken out after demolding, and a titanium-based filter green compact is obtained; the titanium-based filter green compact has a square tube shape, a wall thickness of 15 mm and a porosity of 38%;

[0113] S8, porous titanium-based intermetallic compound filter preparation: the S7 titanium-based filter green compact is placed into a vacuum sintering furnace, vacuumized, and then heated and sintered, the temperature of the vacuum sintering is 1100℃, the vacuum degree is 10 -2 Pa, the sintering time is 3 h, and a high-performance porous titanium-based intermetallic compound filter is obtained.

[0114] The porosity of the porous titanium-based intermetallic compound filter prepared in this embodiment is 35%, the pore size is 90 μm, the hydrogen content is 0.012wt.%, and the compressive strength is 65 MPa.

[0115] Example 4

[0116] A method for preparing a high-performance porous titanium-based intermetallic compound filter, the method comprising the following steps:

[0117] S1, titanium raw material hydrogenation: using a hydrogenation furnace to hydrogenate 30 kg of oil-free surface blocks, the hydrogenation temperature is 400 DEG C, the hydrogenation treatment time is 2 h, the hydrogen content of the easily broken hydrogenated titanium block is 2.9 wt.%, and the easily broken hydrogenated titanium block is obtained;

[0118] S2, micron-sized hydrogenated titanium powder preparation: the S1 easily broken hydrogenated titanium block is put into a ball mill tank filled with high-purity argon protection for high-energy ball milling, the ball-to-material ratio of high-energy ball milling is 8:1, the ball milling speed is 400 rpm, the size of the grinding ball is 6 mm, the ball milling time is 2 h, and the micron-sized hydrogenated titanium powder is obtained; the particle size of the micron-sized hydrogenated titanium powder is 300 μm, and the shape is irregular block;

[0119] S3, mixed powder preparation: the S2 micron-sized hydrogenated titanium powder and 11.3 kg of aluminum powder are mixed by a mixer under high-purity argon protection, the particle size of the aluminum powder is 300 μm, and the aluminum powder is gas-atomized aluminum powder; the atomic ratio of each element in the powder is Ti:Al=0.6:0.4, and the mixed powder is obtained;

[0120] S4, mixed powder dehydrogenation alloying: the S3 mixed powder is put into a vacuum furnace for dehydrogenation treatment, the dehydrogenation temperature is 850 DEG C, the dehydrogenation time is 4 h, the vacuum degree in the vacuum furnace is 10 -2 Pa, and the alloy powder particles are obtained after dehydrogenation; the hydrogen content of the alloy powder particles is 0.08 wt.%;

[0121] S5, micron-sized alloy powder preparation: the S4 alloy powder particles are put into a ball mill tank filled with argon protection, a pore-forming agent is added, the pore-forming agent is NaCl, and the addition amount is 10 wt.% of the alloy powder particles; high-energy ball milling is carried out, the ball-to-material ratio of high-energy ball milling is 5:1, the ball milling speed is 400 rpm, the size of the grinding ball is 6 mm, the ball milling time is 4 h, and the micron-sized alloy powder is obtained; the particle size of the micron-sized alloy powder is 150 μm, and the hydrogen content is 0.08 wt.%;

[0122] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: a silica gel is used to make a tubular soft sleeve, a stainless steel core rod is arranged in the middle of the soft sleeve, the core rod is fixed by silica gel plugs matched with the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched outside the soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, and the cold isostatic forming mold is composed of the soft sleeve, the core rod, the plug and the liner;

[0123] The soft sleeve has a total length of 60 cm, an inner diameter of 100 mm, and a thickness of 10 mm, and has a structure in which the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a corrugated engagement, and the length of the upper end is 1 / 2 of the total length of the sleeve; the stainless steel liner has a left-right split mold structure and is fixed by a throat clamp; the diameter of the core rod is 68 mm, the taper of the core rod is 2°, the length of the liner is 60 cm, the diameter of the liner is 102 mm, the hole diameter of the liner is 5 mm, and the hole area is 50% of the total area of the liner;

[0124] S7, green compact of titanium-based filter preparation: the micron-sized alloy powder of S5 is loaded into the tubular soft sleeve in S6, and sealed and combined; then the powder-loaded forming mold is placed into a cold isostatic pressing machine for cold isostatic pressing, the pressing pressure of the cold isostatic pressing is 120 MPa, the pressure holding time is 120 s, the mold is demolded and taken out, and a green compact of titanium-based filter is obtained; the green compact of titanium-based filter has a tubular shape, a wall thickness of 15 mm, and a porosity of 41%;

[0125] S8, porous titanium-based intermetallic compound filter preparation: the green compact of titanium-based filter of S7 is placed into a vacuum sintering furnace, vacuumized, and then heated and sintered, the sintering temperature is 1200℃, the vacuum degree is 10 -2 Pa, the sintering time is 2 h, and a high-performance porous titanium-based intermetallic compound filter is obtained.

[0126] The porosity of the porous titanium-based intermetallic compound filter prepared in this embodiment is 37%, the pore size is 95μm, the hydrogen content is 0.013wt.%, and the compressive strength is 70 MPa.

[0127] Example 5

[0128] A preparation method of a high-performance porous titanium-based intermetallic compound filter, the preparation method of the high-performance porous titanium-based intermetallic compound filter comprising the following steps:

[0129] S1, titanium raw material hydrogenation: 20 kg of sponge titanium is subjected to hydrogenation treatment by using a hydrogenation furnace, the hydrogenation treatment temperature is 400℃, hydrogen is introduced for 3 h, the hydrogen content in the broken hydrogenated titanium block is 2.8wt.%, and a broken hydrogenated titanium block is obtained;

[0130] S2, micron-sized hydrogenated titanium powder preparation: the broken hydrogenated titanium block of S1 is placed into a ball mill pot filled with high-purity argon protection for high-energy ball milling, the ball-to-material ratio is 10:1, the ball milling speed is 500 rpm, the size of the stainless steel ball is 10 mm, the ball milling time is 2 h, and micron-sized hydrogenated titanium powder is obtained; the particle size of the micron-sized hydrogenated titanium powder is 200μm, and the shape is irregular blocky;

[0131] S3, mixed powder preparation: the S2 micrometer titanium hydride powder is mixed with 35 kg of iron powder in a mixer protected by high-purity argon, the particle size of the iron powder is 200 μm, the iron powder is carbonyl iron powder, the atomic ratio of each element in the powder is Ti:Fe=0.4:0.6, and a mixed powder with uniform mixing is obtained;

[0132] S4, mixed powder dehydrogenation alloying: the mixed powder with uniform mixing in S3 is placed in a vacuum furnace for dehydrogenation treatment, the dehydrogenation temperature of the dehydrogenation treatment is 900℃, the dehydrogenation time is 4h, the vacuum degree in the vacuum furnace is 10 -2 Pa, and the alloy powder particles are obtained after the dehydrogenation is completed; the hydrogen content of the alloy powder particles is 0.08wt.%;

[0133] S5, micrometer alloy powder preparation: the alloy powder particles in S4 are placed in a ball mill tank filled with argon protection, a pore former is added, the pore former is NaCl, the addition amount is 5wt.% of the alloy powder particles; high-energy ball milling is carried out, the ball-to-material ratio of the high-energy ball milling is 10:1, the ball milling speed is 500 rpm, the size of the stainless steel milling ball is 10 mm, the ball milling time is 2h, and a micrometer alloy powder is obtained; the particle size of the micrometer alloy powder is 120 μm, and the hydrogen content is ≤0.08wt.%;

[0134] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: a polyurethane is used to make a square tube-shaped soft sleeve, a stainless steel core rod is arranged in the middle of the soft sleeve, the core rod is fixed by a polyurethane plug matched with the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched outside the polyurethane soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, and the cold isostatic forming mold is composed of the soft sleeve, the core rod, the plug and the liner;

[0135] The total length of the soft sleeve is 80 cm, the inner edge length is 80 mm, the thickness is 10 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a corrugated engagement, the length of the upper end is 3 / 4 of the total length of the sleeve; the stainless steel liner is a left-right split mold structure and is fixed by a throat clamp or a buckle; the edge length of the core rod is 58 mm, the taper of the core rod is 1°, the length of the liner is 80 cm, the diameter of the liner is 82 mm, and the hole diameter of the liner is 3 mm, and the hole area is 60% of the total area of the liner;

[0136] S7, titanium-based filter green compact preparation: the micrometer alloy powder in S5 is loaded into the tubular soft sleeve in S6, and a sealed combination treatment is performed; then the powder-loaded forming mold is placed in a cold isostatic pressing machine for cold isostatic pressing forming, the pressing pressure of the cold isostatic pressing forming is 140 MPa, the pressure holding time is 100 s, the mold is demolded and taken out, and a titanium-based filter green compact is obtained; the titanium-based filter green compact has a square tube shape, a wall thickness of 10 mm, and a porosity of 42%;

[0137] S8, porous titanium-based intermetallic compound filter preparation: the S7 titanium-based filter compact is put into a vacuum sintering furnace, and sintered after vacuumizing, the temperature of vacuum sintering is 1150℃, the vacuum degree is 10 -2 Pa, the sintering time is 2h, and a high-performance porous titanium-based intermetallic compound filter is obtained.

[0138] The porosity of the porous titanium-based intermetallic compound filter prepared in the embodiment is 37%, the pore size is 90μm, the hydrogen content is 0.012wt.%, and the compressive strength is 70MPa.

[0139] Embodiment 6

[0140] A method for preparing a high-performance porous titanium-based intermetallic compound filter, the method comprising the following steps:

[0141] S1, titanium raw material hydrogenation: 40kg of titanium scrap blocks are subjected to hydrogenation treatment by using a hydrogenation furnace, the hydrogenation treatment temperature is 400℃, hydrogen is introduced for 3h, the hydrogen content in the easily broken hydrogenated titanium block is 3.2wt.%, and an easily broken hydrogenated titanium block is obtained;

[0142] S2, micron-sized hydrogenated titanium powder preparation: the S1 easily broken hydrogenated titanium block is put into a ball mill tank filled with high-purity argon protection for high-energy ball milling, the ball-to-material ratio of high-energy ball milling is 5:1, the ball milling speed is 400rpm, the size of the stainless steel milling ball is 6mm, the ball milling time is 3h, and micron-sized hydrogenated titanium powder is obtained; the particle size of the micron-sized hydrogenated titanium powder is 200μm, and the shape is irregular block;

[0143] S3, mixed powder preparation: the S2 micron-sized hydrogenated titanium powder and 42kg of aluminum powder are mixed by using a mixer under high-purity argon protection, the particle size of the aluminum powder is 200μm, and the aluminum powder is gas-atomized aluminum powder; the atomic ratio of each element in the powder is Ti:Al=0.35:0.65, and uniformly mixed powder is obtained;

[0144] S4, mixed powder dehydrogenation alloying: the S3 uniformly mixed powder is put into a vacuum furnace for dehydrogenation treatment, the dehydrogenation temperature is 850℃, the dehydrogenation time is 1h, and the vacuum degree in the vacuum furnace is 10 -2 Pa, and alloy powder particles are obtained after dehydrogenation; the hydrogen content of the alloy powder particles is 0.09wt.%;

[0145] S5, micron-sized alloy powder preparation: put the S4 alloy powder particles into a ball mill tank filled with argon protection, add a pore-forming agent, the pore-forming agent is CaCl2, the addition amount is 5wt.% of the alloy powder particles; carry out high-energy ball milling mixing, the ball-to-material ratio of high-energy ball milling is 10:1, the ball milling speed is 400 rpm, the milling balls are stainless steel balls with a size of 6 mm, the ball milling time is 2 h, to obtain micron-sized alloy powder; the particle size of the micron-sized alloy powder is 120 μm, and the hydrogen content is 0.09wt.%;

[0146] S6, porous titanium-based intermetallic compound filter cold isostatic forming mold preparation: a silica gel is used to make a tubular soft sleeve, a stainless steel mandrel is arranged in the middle of the soft sleeve, the mandrel is fixed by silica gel plugs matched with the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched outside the soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, and the cold isostatic forming mold is formed by the soft sleeve, the mandrel, the plug and the liner.

[0147] The total length of the soft sleeve is 70 cm, the diameter is 80 mm, the thickness is 15 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened through a zigzag or corrugated engagement, the length of the upper end is 3 / 4 of the total length of the sleeve; the stainless steel liner is a left-right split mold structure and is fixed by a throat clamp or a buckle; the diameter of the mandrel is 68 mm, the taper of the mandrel is 1°, the length of the liner is 70 cm, the diameter of the liner is 82 mm, the hole diameter of the liner is 8 mm, and the hole area is 55% of the total area of the liner.

[0148] S7, titanium-based filter green compact preparation: the S5 micron-sized alloy powder is loaded into the tubular soft sleeve in S6, and sealed and combined; then the powder-loaded forming mold is placed into a cold isostatic pressing machine for cold isostatic pressing forming, the pressing pressure of the cold isostatic pressing forming is 120 MPa, the pressure holding time is 120 s, the mold is taken out after demolding, and a titanium-based filter green compact is obtained; the titanium-based filter green compact has a tubular or square tubular shape, a wall thickness of 5 mm and a porosity of 44%.

[0149] S8, porous titanium-based intermetallic compound filter preparation: the S7 titanium-based filter green compact is placed into a vacuum sintering furnace, vacuumized, and then heated and sintered, the temperature of the vacuum sintering is 1150℃, the vacuum degree is 10 -2 Pa, the sintering time is 1 h, and a high-performance porous titanium-based intermetallic compound filter is obtained.

[0150] The porosity of the porous titanium-based intermetallic compound filter prepared in this embodiment is 39%, the pore size is 75 μm, the hydrogen content is 0.011wt.%, and the compressive strength is 60 MPa.

[0151] The scheme has the advantages that the preparation method of the high-performance porous titanium-based intermetallic compound filter can solve the problems of short service life, insufficient filtering precision, complex process flow, incomplete removal of calcium elements, uneven pore distribution, poor high-temperature resistance and corrosion resistance, high preparation cost, poor filtering efficiency, large loss of organic solvents, poor alloying effect and high hydrogen content in the titanium tetrachloride filter in the prior art.

[0152] The raw material cost is low, the preparation process is simple, the flow is short, the industrial applicability is strong, titanium resources are recycled and reused, and the sustainable development of titanium resources is realized.

[0153] In the preparation process, the titanium hydride powder and the aluminum powder or the iron powder simultaneously undergo dehydrogenation and self-propagating reactions in the dehydrogenation process.

[0154] The soft sleeve structure is designed, the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened.

[0155] The intermediate core rod structure design and fixing method ensure that the core rod does not move during powder loading, making the powder loading uniform and the blank wall thickness consistent, and ensuring the straightness of the hollow structure of the filter.

[0156] The porous stainless steel bushing structure design not only ensures the quality of the outer surface of the filter blank, but also ensures the shape and structure of the soft sleeve, so that the long filter blank structure is not deformed and does not have problems such as bending and warping.

[0157] The application uses titanium block as raw material, although the cost of raw material is low, the cost of subsequent crushing and grinding is low, but it will make the hydrogen content in the mixed powder high, affect the normal use and service life of the filter, and the hydrogen content in the prepared mixed powder and the filter needs to be monitored and controlled at any time, so that the hydrogen content in the final filter is controlled to be less than or equal to 0.015wt.%.

[0158] The application adopts titanium raw material block, low-price raw materials such as aluminum and iron, hydrogenation and dehydrogenation, mold design and preparation, and cold isostatic pressing process, can realize near forming of the filter, and the material utilization rate can reach more than 98%, thereby reducing the preparation cost of the filter. In particular, by designing the specifications and shapes of the cold isostatic pressing sleeve, filters required for different application scenarios can be prepared.

[0159] The filter preparation technology involved in the application adopts a short process, near-net-shape powder metallurgy process combined with low-cost raw materials, can meet the filtering demand in extreme environment, is not only suitable for filtering titanium tetrachloride, but also suitable for filtering in other fields, has good process economy, and is suitable for industrial production.

[0160] In summary, compared with other traditional methods, the method of the application takes titanium as a base raw material, adds alloy elements such as aluminum and iron, realizes near-net-shape forming of the porous titanium-based intermetallic compound filter through hydrogenation and dehydrogenation process combined with high-energy ball milling, cold isostatic pressing and vacuum sintering; the prepared filter has high porosity, uniform pore size distribution and excellent corrosion resistance, can be used stably for a long time in a high-temperature and strong-corrosion environment, can realize efficient and high-precision purification of titanium tetrachloride, and is beneficial to industrial large-scale production and promotion.

[0161] It should be understood that the term "and / or" herein only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent three cases of A alone, A and B together, and B alone, wherein A and B can be singular or plural. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects, but can also represent an "and / or" relationship, which can be understood according to the context before and after.

[0162] In the application, "at least one" means one or more, and "a plurality of" means two or more. "At least one of the following" or the like means any combination of the items, including any combination of single item or multiple items. For example, at least one of a, b, or c can represent a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple.

[0163] It should be understood that the size of the sequence number of each process described above does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application.

[0164] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a high-performance porous titanium-based intermetallic compound filter, characterized in that, The preparation method of the high-performance porous titanium-based intermetallic compound filter comprises the following steps: S1, titanium raw material hydrogenation: a hydrogenation furnace is used to hydrogenate titanium raw material blocks to obtain easily broken hydrogenated titanium blocks; S2, micron-sized hydrogenated titanium powder preparation: the easily broken hydrogenated titanium blocks in S1 are put into a ball milling tank filled with high-purity argon protection to perform high-energy ball milling to obtain micron-sized hydrogenated titanium powder; S3, mixed powder preparation: the micron-sized hydrogenated titanium powder in S2 is mixed with aluminum powder or iron powder by using a high-purity argon protection mixer to obtain mixed powder with uniform mixing; S4, mixed powder dehydrogenation alloying: the mixed powder with uniform mixing in S3 is put into a vacuum furnace to perform dehydrogenation treatment, and after the dehydrogenation is completed, alloy powder particles are obtained; S5, micron-sized alloy powder preparation: the alloy powder particles in S4 are put into a ball milling tank filled with argon protection, a pore former is added, and high-energy ball milling is performed to obtain micron-sized alloy powder; S6, porous titanium-based intermetallic compound filter cold isostatic pressing forming mold preparation: a polyurethane or silica gel tube-shaped soft sleeve is made, a stainless steel mandrel is arranged in the middle of the soft sleeve, the mandrel is fixed by a polyurethane or silica gel plug matched with the upper and lower ports of the soft sleeve, a porous stainless steel liner is matched with the polyurethane or silica gel soft sleeve, the length of the liner is consistent with the length of the soft sleeve, and the diameter of the liner is larger than the diameter of the soft sleeve, so as to form a cold isostatic pressing forming mold composed of the soft sleeve, the mandrel, the plug and the liner; the total length of the soft sleeve is 5-200 cm, the thickness is 5-25 mm, the structure is that the lower end is a whole mold and cannot be opened, and the upper end is a split mold and can be partially opened by serrated or corrugated engagement, the length of the upper end is 1 / 2-3 / 4 of the total length of the sleeve; the stainless steel liner is a left-right split mold structure and is fixed by a hose clamp or a buckle, the thickness of the liner is 1-3 mm; the taper of the mandrel is 1-3°, the diameter of the liner is 2-8 mm larger than the diameter of the soft sleeve; the pore diameter of the porous stainless steel liner is 3-20 mm, and the pore area is 50-80% of the outer surface area of the liner; S7, titanium-based filter compact preparation: the micron-sized alloy powder in S5 is loaded into the tubular soft sleeve in S6, and sealed and combined; then the powder-loaded forming mold is placed into a cold isostatic pressing machine to perform cold isostatic pressing forming, and after demolding, a titanium-based filter compact is obtained; S8, porous titanium-based intermetallic compound filter preparation: the titanium-based filter compact in S7 is placed into a vacuum sintering furnace, vacuumized, and then heated and sintered to obtain a high-performance porous titanium-based intermetallic compound filter.

2. The method of producing a high-performance porous titanium-based intermetallic compound filter according to claim 1, characterized by, In S1, the hydrogenation treatment temperature is 300-600℃, the holding time is 1-4 h, the hydrogen content in the easily broken hydrogenated titanium blocks is 2-3.5 wt.%, and the titanium raw material blocks are off-specification titanium, sponge titanium or other titanium waste with no oil stains on the surface.

3. The method of claim 1, wherein the high performance porous titanium-based intermetallic filter is prepared by the steps of: preparing a titanium-based intermetallic alloy powder; and sintering the titanium-based intermetallic alloy powder. In S2, the ball-to-material ratio of high-energy ball milling is 5:1-10:1, the ball milling speed is 300-600 rpm, the milling balls are stainless steel balls with a diameter of 6-10 mm, the ball milling time is 2-4 h, the particle size of the micron-sized hydrogenated titanium powder is 150-500 μm, and the shape is irregular block.

4. The method of claim 1, wherein the high performance porous titanium-based intermetallic filter is prepared by the steps of: preparing a titanium-based intermetallic alloy powder; and sintering the titanium-based intermetallic alloy powder. The particle size of the aluminum powder or iron powder in S3 is 150-500 μm, wherein the aluminum powder is gas atomized aluminum powder, and the iron powder is carbonyl iron powder or reduced iron powder; the atomic ratio of each element in the powder is Ti:Al=(1-X):X, X=0.35-0.66; or Ti:Fe=(1-Y):Y, Y=0.5-0.

6.

5. The method of claim 1, wherein the high performance porous titanium-based intermetallic filter is prepared by the steps of: preparing a titanium-based intermetallic alloy powder; and sintering the titanium-based intermetallic alloy powder. The dehydrogenation temperature in S4 is 600-900°C, the dehydrogenation time is 1-4h, and the vacuum degree in the vacuum furnace is 10 -2 -10Pa, and the hydrogen content of the alloy powder particles is ≤0.1wt.%.

6. The method of producing a high performance porous titanium-based intermetallic compound filter according to claim 1, characterized by, The pore-forming agent in S5 is NaCl, KCl or CaCl2 salt, and the addition amount is 5-10 wt.% of the alloy powder particles; the ball-to-powder ratio of high-energy ball milling is 2:1-10:1, the ball milling speed is 300-600 rpm, the milling balls are stainless steel balls with a diameter of 6-10 mm, the ball milling time is 2-5 h, the particle size of the micron-sized alloy powder is 75-200 μm, and the hydrogen content is ≤0.1 wt.%.

7. The method of producing a high performance porous titanium-based intermetallic compound filter according to claim 1, characterized by, The pressing pressure of the cold isostatic pressing in S7 is 80-200 MPa, the pressure holding time is 60 s-240 s, the shape of the titanium-based filter compact is tubular, the wall thickness is 10-20 mm, and the porosity is 30-55%.

8. The method of producing a high performance porous titanium-based intermetallic compound filter according to claim 1, characterized by, The temperature for vacuum sintering in S8 is 1000-1200℃, and the vacuum degree is 1-10 -2 Pa, and the sintering time is 1-4h.

9. The method of producing a high performance porous titanium-based intermetallic compound filter according to claim 1, characterized by, The porosity of the porous titanium-based intermetallic compound filter in S8 is 30-60%, the pore size is 10-100 μm, the hydrogen content is ≤0.015 wt.%, and the compressive strength is ≥50 MPa.

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