A method for preparing a refractory element-containing high-boron silicon nickel-based solder alloy powder

Abstract

The application relates to a preparation method of high-boron-silicon nickel-based brazing filler metal alloy powder containing refractory elements, which comprises the following steps: preparing raw materials according to chemical components; the raw materials include main materials and raw materials for providing refractory elements; the refractory elements include B and Si; the main materials are subjected to melting and high-temperature refining treatment; then, the temperature of the melt is reduced to a first temperature under a protective atmosphere, the raw materials for providing the refractory element Si are added into the melt, the melt is smelted for a first set time, and then casting treatment is carried out to obtain a master alloy; the master alloy is subjected to heating, melting and high-temperature refining treatment; then, the temperature of the melt is reduced to a second temperature under a protective atmosphere, NiB alloy is added into the melt, the melt is smelted for a second set time, and then gas atomization treatment is carried out to obtain the high-boron-silicon nickel-based brazing filler metal alloy powder containing refractory elements. The application is used for preparing the high-boron-silicon nickel-based brazing filler metal alloy powder containing refractory elements with good chemical component uniformity and avoiding production accidents such as furnace leakage.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of brazing materials, in particular to a preparation method of high-boron-silicon nickel-based brazing alloy powder containing refractory elements. BACKGROUND

[0002] High-temperature alloys have a use amount of more than 50% in advanced aero-engines due to excellent high-temperature comprehensive performance, in actual application, many parts have complex shapes, and it is difficult to integrally cast, so the parts are usually connected in combination through brazing.

[0003] Brazing is one of practical and reliable welding technologies, which uses a metal material with a lower melting point than a base material as a filler metal, the filler metal completely wets and fills the connecting gap between the base material at a temperature lower than the melting point of the base material and higher than the melting point of the filler metal, interacts with the base material, and then cools and solidifies to form a connection, the working temperature of the joint is 950-1200 DEG C, and the brazing is widely applied to the fields of aerospace, energy, chemical industry and the like.

[0004] Nickel-based brazing filler metal has high tensile strength, shear strength and good oxidation resistance, corrosion resistance and the like at a working temperature, and is widely used. Among them, gas atomization powder preparation is the most important preparation method of nickel-based powder brazing filler metal.

[0005] Regarding the gas atomization preparation method of nickel-based powdered brazing filler metal, two publicly reported methods are listed here. Method 202010885610.X uses a vacuum induction melting gas atomization powder preparation equipment to prepare nickel-manganese-chromium-cobalt-boron brazing filler metal powder. The main preparation steps include placing the metal raw material into a crucible for melting. The melting temperature is raised to 1270-1370℃ and held for 10-15 minutes to completely melt the metal raw material to obtain an alloy liquid. The alloy liquid is poured into an intermediate ladle, which is preheated to 1000-1100℃, and the atomization pressure is 2.5-4 MPa. Patent application 201710748819.X discloses a NiCrCoWAlMoFeTiSiB powder solder for joining nickel-based single-crystal high-temperature alloys, its preparation method, and its application. The main preparation steps include component mixing, melting the master alloy in a vacuum induction furnace, and the melting process being: holding at 1550-1600℃ for 1 min, holding at 1450-1550℃ for 10 min, holding at 1300-1400℃ for 10 min, and casting at 1400-1450℃. The master alloy ingot is then prepared into alloy powder using an atomization powdering method. Specifically, the powder spraying temperature is 1400-1530℃, the holding time is 5-20 min, and the atomization pressure is 3-8 MPa. From the above two reported methods and other unlisted prior art, it is clear that the preparation process and key technical parameters of nickel-based solders with different compositions and technical requirements vary greatly, and there is no unified preparation process method. This is because nickel-based solders have a complex composition. They are based on a nickel solid solution and contain various solid solution elements and reinforcing elements to form a complex phase structure, in order to meet the performance requirements of the joints under different usage conditions.

[0006] The preparation of high boron silicon nickel-based solder alloy powder containing refractory elements presents at least the following problems:

[0007] (1) Due to the high boron and silicon content in high boron silicon nickel-based brazing filler metal, the melt will have a strong corrosive effect on the crucible during smelting, which can easily lead to production accidents such as furnace leakage.

[0008] (2) Due to the addition of multiple elements in the composition design of high boron silicon nickel-based brazing filler metal, in addition to B and Si melting point degrading elements, Cr, Co, Fe and refractory elements (such as W, Mo, Nb) and active elements (such as Al, Ti) are selectively added to meet the performance requirements of the joint under the conditions of use.

[0009] However, the properties of many elements vary greatly, such as melting point and density. W has a melting point of 3410℃ and a density of 19.25 g / cm³. 3 Mo has a melting point of 2620℃ and a density of 10.28 g / cm³. 3 Al has a melting point of 660℃ and a density of 2.7 g / cm³. 3; B has a melting point of 2300℃ and a density of 2.34g / cm 3 For example, the content of the melting-reducing element is high (high boron-silicon), so that the melting point of the melt is reduced, but this is not conducive to the melting of the refractory element. In summary, these elements with large differences in properties are prone to macrosegregation, so how to ensure the uniformity of the alloy composition during melting and atomization is a technical problem.

[0010] In summary, the high boron-silicon nickel-based filler containing refractory elements at least has the above problems, so the preparation process of other nickel-based filler powder cannot be simply copied. Therefore, there is an urgent need for a preparation process of high boron-silicon nickel-based filler alloy powder containing refractory elements. SUMMARY

[0011] Therefore, the present application provides a preparation method of high boron-silicon nickel-based filler alloy powder containing refractory elements, which can prepare high boron-silicon nickel-based filler alloy powder containing refractory elements with good chemical composition uniformity and avoid production accidents such as furnace leakage.

[0012] To achieve the above-mentioned purpose, the present application mainly provides the following technical scheme:

[0013] The present application provides a preparation method of high boron-silicon nickel-based filler alloy powder containing refractory elements, wherein the preparation method comprises the following steps:

[0014] Step 1): preparing raw materials according to chemical composition; wherein the raw materials include main materials, raw materials for providing melting-reducing elements; the melting-reducing elements include B and Si; the main materials are used to provide elements including one or more of Ni, C, refractory elements, Co, Cr, Zr and Hf; preferably, the raw materials further include raw materials for providing active elements, and the active elements include one or more of Al, Ti and Mn;

[0015] Step 2): first, melting and high-temperature refining treatment is performed on the main materials; then, under a protective atmosphere, the temperature of the melt is reduced to a first temperature, raw materials for providing melting-reducing element Si are added, and after melting for a first set time, casting treatment is performed to obtain a master alloy; preferably, when the raw materials include raw materials for providing active elements, the raw materials for providing active elements are also added when the raw materials for providing melting-reducing element Si are added;

[0016] Step 3): first, heating, melting and high-temperature refining treatment is performed on the master alloy; then, under a protective atmosphere, the temperature of the melt is reduced to a second temperature, raw materials for providing melting-reducing element B are added, and after melting for a second set time, gas atomization treatment is performed to obtain high boron-silicon nickel-based filler alloy powder containing refractory elements.

[0017] Preferably, in the refractory element-containing high-boron-silicon nickel-based brazing filler material: the total content of Si and B elements is greater than 3wt%; the refractory element includes one or more of W, Mo, Ta, and Nb.

[0018] Preferably, in the step 1), the raw material for providing the melting-point-lowering element B is selected from a NiB intermediate alloy; and the raw material for providing the melting-point-lowering element Si is selected from elemental Si.

[0019] Preferably, in the step 2), before melting and high-temperature refining of the main material, the main material is loaded into a melting furnace crucible in the following order: when the main material is used to provide elements including C element, nickel is first added, then NiC, then one or more of Co, Cr, Zr, and Hf, then refractory element single substance, and finally nickel; when the main material is used to provide elements not including C element, nickel is first added, then one or more of Co, Cr, Zr, and Hf, then refractory element single substance, and finally nickel.

[0020] Preferably, in the step 2), vacuum is applied, the main material is melted by heating under a vacuum degree of not more than 10 Pa, and then high-temperature refining is performed; after high-temperature refining, vacuum is stopped, protective gas is filled, the melt is cooled to a first temperature, elemental Si is added to the melt, and then the melt is continuously melted for a first set time before being cast into a master alloy. Preferably, when the raw material includes raw material for providing active elements, elemental active substance is also added when elemental Si is added. Preferably, the high-temperature refining temperature is 80-300°C higher than the liquidus temperature, and the high-temperature refining time is 3-8 min; and the protective gas is selected from argon. Preferably, the first temperature is 10-50°C higher than the liquidus temperature; and the first set time is 2-5 min.

[0021] Preferably, in the step 3), the master alloy is placed in an atomization furnace crucible, vacuum is applied, the master alloy is melted by heating under a vacuum degree of not more than 10 Pa, and then high-temperature refining is performed; after high-temperature refining, vacuum is stopped, protective gas is filled to normal pressure in the furnace body, the melt is cooled to a second temperature, NiB intermediate alloy is added to the melt for a second set time, and then atomization treatment is performed. Preferably, the high-temperature refining temperature is 80-300°C higher than the liquidus temperature, and the refining time is 3-8 min; the second temperature is 10-50°C higher than the liquidus temperature; the second set time is 2-5 min; and the atomization treatment conditions are as follows: the atomization medium is argon, the atomization pressure is 6-10 MPa, and the alloy liquid flow rate is 3.0-5.0 kg / min.

[0022] Preferably, after the step 3), the method further includes:

[0023] Step 4): Particle size classification is performed on the refractory element-containing high-boron-silicon nickel-based brazing filler alloy powder prepared in step 3).

[0024] Compared with the prior preparation method, the preparation method of the refractory element-containing high-boron-silicon nickel-based brazing filler alloy powder of the present application has at least the following beneficial effects:

[0025] (1) The preparation method of the refractory element-containing high-boron-silicon nickel-based brazing filler alloy powder provided by the present application, wherein boron and silicon are very important elements in the high-boron-silicon nickel-based brazing filler, which play a role in reducing the melting point, improving the wettability and flowability, etc. The total content of boron and silicon in the high-boron-silicon nickel-based brazing filler of the present application is high, greater than 3wt%, resulting in the characteristics of the melt with low melting point, good flowability, good wettability, and strong permeability, so that the melt has strong erosion effect on the crucible during smelting. The preparation method of the present application adopts the secondary addition of melting point reducing elements method, that is, after smelting the raw materials to prepare the master alloy in the vacuum melting furnace, the raw material providing Si element is added in the later stage, and the NiB intermediate alloy providing B is added in the later stage of smelting the master alloy and before atomization in the ultrasonic gas atomization furnace, so that the erosion of the melt on the crucible can be reduced, the service life of the crucible can be prolonged, the production accidents such as leakage can be reduced, and the stability and reliability of large-scale production can be ensured.

[0026] (2) The melting point of the refractory element-containing high-boron-silicon nickel-based brazing filler alloy powder provided by the present application is usually around 1000-1200℃, however, the refractory elements contained therein have very high melting points, for example, the melting point of W is 3410℃, the melting point of Mo is 2620℃, while the active elements have a lower melting point, for example, the melting point of Al is 660℃, and B and Si also belong to melting point reducing elements. In order to improve the composition uniformity of each element, the present application adopts the method of optimizing the feeding sequence combined with the control of smelting parameters to effectively control the composition of the alloy powder: for example, (1) when smelting to prepare the master alloy, the main materials (Ni, NiC, one or more of refractory elements, Co, Cr, Zr, Hf) are smelted first, and the feeding sequence is required, that is, nickel and NiC are added first, then one or more of Co, Cr, Zr, Hf are added, then the refractory element is added, and finally nickel is added, the high-temperature refining temperature is high and the time is relatively long, so that the refractory alloy is fully melted; then the protective gas is filled, the melt is cooled to the first temperature, and the active elements and melting point reducing elements are added to the melt at the same time, and the smelting time is reduced to reduce the burning loss of the active elements.

[0027] (3) The present application adopts the pre-prepared master alloy method, that is, the active elements are added to form a master alloy ingot in the later stage of smelting the main materials in the vacuum melting furnace, which can greatly reduce the burning loss of the active elements when smelting the melt in the ultrasonic gas atomization furnace, and at the same time, it can avoid the splashing when adding the active elements to the melt before atomization, and greatly improve the controllability of the composition of the active elements.

[0028] Therefore, the chemical composition and uniformity of the refractory element-containing high-boron silicon nickel-based brazing filler alloy powder obtained by the preparation process are effectively controlled, material guarantee for preparing high-quality welds is provided, the powder can be widely applied to the fields of aviation, metallurgy, machinery, electric power and the like, and has remarkable social and economic benefits.

[0029] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, and to implement the content of the description, the following will be described in detail with the preferred embodiments of the present application. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following will be described in detail with the preferred embodiments, the specific implementation, structure, features and effects according to the present application. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0031] In one aspect, the present application provides a preparation method of a refractory element-containing high-boron silicon nickel-based brazing filler alloy powder, which mainly comprises the following steps:

[0032] Step 1): preparing raw materials according to chemical composition; the raw materials include main materials and raw materials for providing reducing elements. Preferably, the raw materials also include raw materials for providing active elements,

[0033] The reducing elements include B and Si; wherein the B element is added by selecting NiB intermediate alloy material, and the Si is added by selecting elemental raw material.

[0034] The main materials for providing raw materials include one or more of Ni, NiC, refractory elements, Co, Cr, Zr and Hf; the raw material adding form can be elemental and / or intermediate alloy material of these elements; the refractory elements include one or more of W, Mo, Ta and Nb, in the form of elemental raw material.

[0035] The active elements include one or more of Al, Ti and Mn, and the raw materials for providing active elements are elemental raw materials.

[0036] Step 2): first, the main materials are melted and subjected to high-temperature refining treatment; then, under a protective atmosphere, the temperature of the melt is reduced to a first temperature, the raw material for providing reducing element Si (preferably, the raw material for providing active element is also added) is added, the melt is smelted for a first set time, and then subjected to casting treatment to obtain a master alloy.

[0037] In this step, the raw material providing the melting point reducing element Si and the raw material providing the active element are charged into the auxiliary charging hopper of the smelting furnace. The main material is charged into the smelting furnace crucible in the order from bottom to top as follows: nickel - NiC-Co, Cr, Zr, Hf one or several of them - refractory element single substance - nickel; or nickel - Co, Cr, Zr, Hf one or several of them - refractory element single substance - nickel. Vacuum is drawn, and when the vacuum degree is not greater than 10 Pa, the raw material is heated to be melted, and then high-temperature refining treatment is performed, wherein the temperature of the high-temperature refining treatment is 80-300°C higher than the liquidus, and the time is 3-8 min. After the high-temperature refining treatment, the vacuum is stopped, argon is filled into the furnace, and when the temperature of the melt is 10-50°C higher than the liquidus temperature, the raw material providing the melting point reducing element Si (and preferably the raw material providing the active element) is added to the melt, and the smelting is continued for 2-5 min, and then the master alloy is cast. After the master alloy is cooled, the surface is polished to be bright, and then it is ready for use.

[0038] Step 3): The master alloy is first subjected to heating and melting, and high-temperature refining treatment; then, under a protective atmosphere, the temperature of the melt is reduced to a second temperature, and then NiB alloy is added thereto, and after smelting for a second set time, atomization treatment is performed, to obtain high-boron silicon nickel-based solder alloy powder containing refractory elements.

[0039] This step is specifically as follows: (1) the master alloy is placed in the atomization furnace crucible, and the NiB alloy is charged into the auxiliary charging hopper of the atomization furnace. Vacuum is drawn, and when the vacuum degree is not greater than 10 Pa, the master alloy is heated to be melted, and then high-temperature refining treatment is performed, wherein the temperature of the high-temperature refining treatment is 80-300°C higher than the liquidus, and the time is 3-8 min. After the high-temperature refining treatment, the vacuum is stopped, argon is filled into the furnace to normal pressure, and when the temperature of the melt is 10-50°C higher than the liquidus temperature, the NiB alloy is added to continue smelting for 2-5 min, and then atomization is started to obtain alloy powder, the atomization medium is argon, the atomization pressure is 6-10 MPa, and the alloy liquid flow rate is 3.0-5.0 kg / min.

[0040] Step 4): The high-boron silicon nickel-based solder alloy powder containing refractory elements prepared in step 3) is subjected to particle size classification.

[0041] The present application is further illustrated by the following specific examples:

[0042] Example 1

[0043] In this example, BNi57NbCoWCrAlSiMoTi(C) solder alloy powder is prepared, and the main preparation steps are as follows:

[0044] Step 1): Preparation of raw materials

[0045] The raw materials are prepared according to the chemical composition of the BNi57NbCoWCrAlSiMoTi(C) brazing alloy powder: Ni, Co, Cr, Si, W, Mo, Nb, Ti, Al elements and NiB alloy (B content 18.90wt%) and NiC alloy (C content 2.4%).

[0046] Step 2) Preparation of the master alloy ingot by using a vacuum induction melting furnace

[0047] 21) Put Al, Ti and Si elements into the auxiliary hopper of the melting furnace;

[0048] 22) Put the main materials into the melting furnace crucible in the following order from bottom to top: nickel - nickel-carbon intermediate alloy - Co, Cr - W, Mo, Nb - nickel;

[0049] 23) Vacuumize, heat when the vacuum degree is not more than 10 Pa to melt the raw materials, then perform high-temperature refining, high-temperature refining temperature 1530℃, time 5 min;

[0050] 24) After high-temperature refining, stop vacuumizing, fill argon into the furnace to cool the melt to 1430℃, then add Al, Ti and Si into the melt, continue melting for 3 min and then cast into a master alloy ingot;

[0051] 25) After the master alloy ingot is cooled, polish the surface to bright and reserve;

[0052] Step 3) Preparation of the brazing alloy powder by using an ultrasonic gas atomization furnace

[0053] 31) Put the master alloy ingot into the atomization furnace crucible, put the NiB alloy into the auxiliary hopper of the atomization furnace;

[0054] 32) Vacuumize, heat when the vacuum degree is not more than 10 Pa to melt the master alloy ingot, then perform high-temperature refining, high-temperature refining temperature 1420℃, time 5 min;

[0055] 33) After high-temperature refining, stop vacuumizing, fill argon into the furnace to normal pressure, when the melt temperature is 1320℃, add the NiB alloy to continue melting for 3 min and then start atomization to obtain the alloy powder, the atomization medium is argon, the atomization pressure is 9 MPa, and the alloy liquid flow rate is 4 kg / min;

[0056] Step 4) Screen the powder prepared in step 3, the particle size specification is less than 106μm.

[0057] The chemical composition of the BNi57NbCoWCrAlSiMoTi(C) brazing alloy powder prepared in this embodiment is shown in Table 1.

[0058] Table 1 Chemical composition of BNi57NbCoWCrAlSiMoTi(C) powder prepared in Example 1

[0059]

[0060] The yield of the BNi57NbCoWCrAlSiMoTi(C) solder alloy powder prepared in Example 1 was 81.7%.

[0061] In addition, when the BNi57NbCoWCrAlSiMoTi(C) solder alloy powder was prepared by the method of Example 1, the average leakage rate was 5%.

[0062] It can be seen that the BNi57NbCoWCrAlSiMoTi(C) solder alloy powder prepared in Example 1 has good chemical composition uniformity (maximum composition deviation ≤0.06wt%), high yield, and low leakage rate.

[0063] Comparative Example 1

[0064] Comparative Example 1 used the existing conventional technology to prepare the BNi57NbCoWCrAlSiMoTi(C) solder alloy powder, and the main preparation steps were as follows:

[0065] Step 1) Preparation of raw materials

[0066] The raw materials were prepared according to the chemical composition of the BNi57NbCoWCrAlSiMo solder alloy powder: Ni, Co, Cr, Si, W, Mo, Nb, Ti, Al elements, and NiB alloy (B content 18.90wt%) and NiC alloy (C content 2.4%).

[0067] Step 2) Preparation of BNi57NbCoWCrAlSiMoTi(C) solder alloy powder by vacuum induction melting and atomization integrated furnace

[0068] 21) Load Al and Ti elements into the auxiliary feeding hopper;

[0069] 22) Load the main materials into the crucible in the following order from bottom to top: nickel - NiC, NiB, Si - Co, Cr - W, Mo, Nb - nickel;

[0070] 23) Vacuumize, heat to melt the raw materials when the vacuum degree is not greater than 10 Pa, and then perform high-temperature refining, with a high-temperature refining temperature of 1350°C and a time of 5 min.

[0071] 24) After high temperature refining, stop vacuumizing, fill argon into the furnace to normal pressure, let the melt cool to 1250°C, then add Al, Ti into the melt, continue to melt for 3 minutes, then start atomization to get the alloy powder, the atomization medium is argon, the atomization pressure is 9 MPa, the alloy liquid flow rate is 4 kg / min.

[0072] Step 3) Screen the powder prepared in Step 2, the particle size specification is less than 106 μm. The chemical composition of the BNi57NbCoWCrAlSiMoTi(C) brazing alloy powder prepared in this comparative example is shown in Table 2.

[0073] Table 2 Chemical composition of BNi57NbCoWCrAlSiMoTi(C) powder prepared in Comparative Example 1

[0074]

[0075] The yield of the BNi57NbCoWCrAlSiMoTi(C) brazing alloy powder prepared in Comparative Example 1 is 72.8%.

[0076] When the BNi57NbCoWCrAlSiMoTi(C) brazing alloy powder is produced by the method of Comparative Example 1, the average leakage rate is 14%.

[0077] It can be seen that, compared with Example 1, the chemical composition of the BNi57NbCoWCrAlSiMoTi(C) brazing alloy powder prepared in Comparative Example 1 meets the technical index requirements, but the composition uniformity is poor, especially the fluctuation of refractory elements Mo and W and active elements Al and Ti is large (the maximum composition deviation is >0.2 wt%). In addition, the yield of the powder of Comparative Example 1 is low, and the leakage rate is low.

[0078] Example 2

[0079] In this example, B-Ni60CoCrWSiBMo brazing alloy powder is prepared, and the preparation process is as follows:

[0080] Step 1) Preparation of raw materials

[0081] The raw materials Ni, Co, Cr, Si, W, Mo and NiB alloy (B content 18.90 wt%) are prepared according to the chemical composition of the B-Ni60CoCrWSiBMo brazing alloy powder.

[0082] Step 2) Preparation of master alloy ingot by vacuum induction melting furnace

[0083] 21) The elemental Si is loaded into the auxiliary hopper of the melting furnace;

[0084] 22) The furnace charge is loaded into the crucible of the smelting furnace in the following order from bottom to top: Ni-Co, Cr-W, Mo-Ni;

[0085] 23) Vacuum is drawn and the raw material is melted by heating when the vacuum degree is not more than 10 Pa. High temperature refining is carried out after the surface of the melt is stabilized, the high temperature refining temperature is 1550°C, and the time is 5 min;

[0086] 24) After high temperature refining, vacuum is stopped, argon is filled into the furnace to cool the melt to 1450°C, then Si is added into the melt, and the melt is continued to be smelted for 3 min before being cast into a master alloy ingot;

[0087] 25) After the master alloy ingot is cooled, the surface is polished to be bright and is ready for use;

[0088] Step 3): The filler metal powder is prepared by using an ultrasonic gas atomizing furnace

[0089] 31) The master alloy ingot is placed in the crucible of the atomizing furnace, and the NiB alloy is loaded into the auxiliary charging hopper of the atomizing furnace;

[0090] 32) Vacuum is drawn and the master alloy ingot is melted by heating when the vacuum degree is not more than 10 Pa. High temperature refining is carried out after the surface of the melt is stabilized, the high temperature refining temperature is 1350°C, and the time is 4 min;

[0091] 33) After high temperature refining, vacuum is stopped, argon is filled into the furnace to reach normal pressure, the NiB alloy is added when the temperature of the melt is 1250°C, and the melt is continued to be smelted for 3 min before atomization to obtain the alloy powder, the atomizing medium is argon, the atomizing pressure is 9 MPa, and the alloy liquid flow rate is 4 kg / min;

[0092] Step 4): The powder prepared in step 3) is sieved, and the particle size specification is less than 106 μm.

[0093] The chemical composition of the B-Ni60CoCrWSiBMo filler metal alloy powder prepared in Example 2 is shown in Table 3.

[0094] Table 3 Chemical composition of the B-Ni60CoCrWSiBMo filler metal alloy powder prepared in Example 2

[0095]

[0096] The yield of the B-Ni60CoCrWSiBMo filler metal alloy powder prepared in Example 2 is 86.5%.

[0097] When the B-Ni60CoCrWSiBMo filler metal alloy powder is produced by using the preparation method of Example 2, the average leakage rate is 4%.

[0098] It can be seen that the B-Ni60CoCrWSiBMo brazing filler alloy powder prepared in Example 2 has good chemical composition uniformity (maximum composition deviation ≤0.06wt%), high yield and low leakage rate.

[0099] Comparative Example 2

[0100] Step 1) Preparation of raw materials

[0101] The raw materials Ni, Co, Cr, Si, W, Mo and NiB alloy (B content 18.90wt%) were prepared according to the chemical composition of the B-Ni60CoCrWSiBMo brazing filler alloy powder.

[0102] Step 2) Preparation of B-Ni60CoCrWSiBMo brazing filler alloy powder by vacuum induction melting and atomization integrated furnace

[0103] 21) The raw materials were loaded into the crucible in the order of nickel-NiB, Si-Co, Cr-W, Mo-nickel from bottom to top;

[0104] 22) Vacuum was drawn, and when the vacuum degree was not greater than 10 Pa, the raw materials were melted by heating, and then high temperature refining was performed, the high temperature refining temperature was 1350°C, and the time was 5 min;

[0105] 23) After high temperature refining, the vacuum was stopped, argon was filled into the furnace to normal pressure, and the melting was continued for 3 min, and then the atomization was started to obtain the alloy powder, the atomization medium was argon, the atomization pressure was 9 MPa, and the alloy liquid flow rate was 4 kg / min;

[0106] Step 3) The powder prepared in step 2 was sieved, and the particle size specification was less than 106μm.

[0107] The chemical composition of the B-Ni60CoCrWSiBMo brazing filler alloy powder prepared in Comparative Example 2 is shown in Table 4.

[0108] Table 4 Chemical composition of B-Ni60CoCrWSiBMo brazing filler alloy powder prepared in Comparative Example 2

[0109]

[0110] The yield of the B-Ni60CoCrWSiBMo brazing filler alloy powder prepared in Comparative Example 2 was 74.7%.

[0111] When the B-Ni60CoCrWSiBMo brazing filler alloy powder was produced by the preparation method of Comparative Example 2, the average leakage rate was 12%.

[0112] It can be seen that, compared with Example 2, the chemical composition uniformity of the B-Ni60CoCrWSiBMo brazing filler alloy powder prepared in Comparative Example 2 is poor, especially the fluctuation of refractory elements Mo and W is large (the maximum composition deviation is >0.2wt%), and the yield of the finished product and the furnace leakage rate of Comparative Example 2 are low.

[0113] In summary, the refractory element-containing high-boron silicon nickel-based brazing filler alloy powder prepared by the preparation method of the embodiment of the present application has uniform composition, high yield of finished product and low furnace leakage rate, and provides important material guarantee for solving the high-performance connection problem of high-temperature alloy parts.

[0114] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A method for preparing a high-borosilicate nickel-based solder alloy powder containing refractory elements, characterized in that, The preparation method includes the following steps: Step 1): Prepare raw materials according to their chemical composition; wherein the raw materials include main materials and raw materials providing melting point reducing elements; the melting point reducing elements include B and Si; the main materials are provided with one or more of Ni, C, refractory elements, Co, Cr, Zr, and Hf; wherein the raw materials also include raw materials providing active elements, and the active elements include one or more of Al, Ti, and Mn; wherein the refractory elements include one or more of W, Mo, Ta, and Nb; Step 2): First, the main material is melted and refined at high temperature; then, under a protective atmosphere, the temperature of the melt is reduced to a first temperature, and raw materials that provide the melting point reducing element Si are added to it. After melting for a first set time, casting is performed to obtain the master alloy; wherein, when the raw materials include raw materials that provide active elements, raw materials that provide active elements are also added when adding raw materials that provide the melting point reducing element Si. Step 3): First, the master alloy is heated and melted, and then refined at high temperature. Then, under a protective atmosphere, the temperature of the melt is reduced to a second temperature, and raw materials that provide melting point reduction element B are added to it. After melting for a second set time, gas atomization treatment is performed to obtain high boron silicon nickel-based brazing alloy powder containing refractory elements.

2. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to claim 1, characterized in that, In the high boron silicon nickel-based solder containing refractory elements: the total content of Si and B elements is greater than 3 wt%.

3. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to claim 1 or 2, characterized in that, In step 1): the raw material for providing the melting point reducing element B is selected from NiB master alloy; the raw material for providing the melting point reducing element Si is selected from elemental Si.

4. The method for preparing high boron silicon nickel-based brazing alloy powder containing refractory elements according to any one of claims 1-3, characterized in that, In step 2): Before the main material is melted and refined at high temperature, the following order is followed when loading the main material into the crucible of the melting furnace: When the main material is supplied with elements including C: first add some nickel, NiC, then add one or more of Co, Cr, Zr, and Hf, then add the refractory element, and finally add some nickel. When the main material does not include C: first add some nickel, then add one or more of Co, Cr, Zr, and Hf, then add a refractory element, and finally add some nickel.

5. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to any one of claims 1-4, characterized in that, In step 2): Vacuum is applied, and the main material is heated to melt under a vacuum degree of no more than 10 Pa, followed by high-temperature refining. After high-temperature refining, vacuum is stopped, protective gas is introduced, and the melt is cooled to a first temperature. Elemental Si is added to the melt, and after continuing to melt for a first time, it is cast into a master alloy. When the raw materials include raw materials that provide active elements, elemental active elements are also added when adding elemental Si.

6. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to claim 5, characterized in that, In step 2): The high-temperature refining process takes place at a temperature 80-300°C above the liquidus and lasts for 3-8 minutes; argon is used as the protective gas.

7. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to claim 5, characterized in that, In step 2): The first temperature is 10-50°C higher than the liquidus temperature; the first set time is 2-5 minutes.

8. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to any one of claims 1-7, characterized in that, In step 3): The master alloy is placed in the crucible of the atomizing furnace, a vacuum is drawn, and the master alloy is heated under a vacuum degree of no more than 10 Pa to melt it, and then high-temperature refining is carried out. After high-temperature refining, the vacuuming is stopped, and protective gas is introduced into the furnace to atmospheric pressure. After the melt temperature drops to the second temperature, NiB master alloy is added to the melt and the melting continues for the second set time, followed by atomization treatment.

9. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to claim 8, characterized in that, In step 3): The high-temperature refining temperature is 80-300°C above the liquidus, and the refining time is 3-8 minutes; the second temperature is 10-50°C above the liquidus temperature; and / or The second set time is 2-5 minutes; and / or The atomization conditions are as follows: the atomization medium is argon gas, the atomization pressure is 6-10 MPa, and the alloy liquid flow rate is 3.0-5.0 kg / min.

10. The method for preparing high boron silicon nickel-based solder alloy powder containing refractory elements according to any one of claims 1-9, characterized in that, Following step 3), the following is also included: Step 4): Perform particle size classification on the high boron silicon nickel-based brazing alloy powder containing refractory elements prepared in Step 3).

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