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CN-121972863-A - Wear-resistant brazing paste, preparation method thereof and brazing method

CN121972863ACN 121972863 ACN121972863 ACN 121972863ACN-121972863-A

Abstract

The invention relates to the technical field of heavy-duty part surface strengthening, in particular to wear-resistant brazing paste, a preparation method thereof and a brazing method. The brazing paste comprises brazing powder, a hard phase, a solvent, a thixotropic agent and a soldering flux, wherein the hard phase comprises diamond and Fe 3 O 4 coated on at least part of the surface of the diamond. The preparation method comprises the steps of adding a silane coupling agent into diamond after hydrolysis, heating and stirring to form a protective film on the surface of the diamond, adding Fe 3 O 4 , heating and stirring, dehydrating and condensing hydroxyl groups on the surface of Fe 3 O 4 and silanol hydroxyl groups to form an Fe 3 O 4 layer in situ, mixing the Fe 3 O 4 layer with a solvent, a thixotropic agent, brazing filler metal powder and a soldering flux, and carrying out vacuum degassing and aging to obtain the brazing filler metal paste. The brazing paste can form double protection on diamond, effectively improve the burning loss condition of the diamond, simultaneously endow the diamond with magnetism, drive the diamond to be uniformly distributed through induction heating, and remarkably improve the wear resistance of the coating.

Inventors

  • ZHANG LEI
  • CHENG ZHAN
  • LV XIANMING

Assignees

  • 中国机械总院集团宁波智能机床研究院有限公司
  • 中国机械总院集团郑州机械研究所有限公司

Dates

Publication Date
20260505
Application Date
20260326

Claims (10)

  1. 1. The wear-resistant brazing paste is characterized by comprising brazing filler metal powder, a hard phase, a solvent, a thixotropic agent and a soldering flux, wherein the hard phase comprises diamond and Fe 3 O 4 coated on at least part of the surface of the diamond.
  2. 2. The wear-resistant brazing paste according to claim 1, wherein the brazing paste comprises, by mass, 10-12 parts of diamond, 5-8 parts of Fe 3 O 4 , 12-15 parts of a silane coupling agent, 48-60 parts of brazing filler metal powder, 5-7 parts of a solvent, 2-4 parts of a thixotropic agent, 7-10 parts of a soldering flux and 0.5-1 part of a silane hydrolysis agent; Wherein, si atoms in the silane coupling agent are connected with at least two alkoxy groups, the silane hydrolysis agent comprises water, and the diamond is diamond with hydroxyl groups on the surface.
  3. 3. The wear resistant braze paste as claimed in claim 2, wherein at least one of the following characteristics is met: (1) The silane coupling agent comprises at least one of vinyl triethoxysilane, aminopropyl trimethoxysilane, gamma-mercaptopropyl trimethoxysilane and N-aminoethyl-3-aminopropyl methyl dimethoxy silane; (2) The brazing filler metal powder comprises nickel-based brazing filler metal powder and/or copper-based brazing filler metal powder; (3) The solvent comprises at least one of glycerol, propylene glycol, diethylene glycol methyl ether and tripropylene glycol methyl ether; (4) The thixotropic agent comprises polyamide wax and/or hydrogenated castor oil; (5) The soldering flux comprises borax and/or boric acid; (6) The average grain diameter of the diamond is 30-50 mu m; (7) The average grain diameter of Fe 3 O 4 is 5-10nm; (8) The particle size of the brazing filler metal powder is 200-300 meshes.
  4. 4. A method of preparing a wear resistant braze paste as claimed in any one of claims 1 to 3, comprising the steps of: S1, adding a silane hydrolysis agent into a silane coupling agent for hydrolysis reaction, so that alkoxy on the silane coupling agent is converted into silanol hydroxyl to obtain hydrolysis liquid; s2, adding diamond into the hydrolysate, heating and stirring, and coating the hydrolyzed silane coupling agent on the surface of the diamond to form a protective film to obtain a first solution; S3, adding Fe 3 O 4 into the first solution, heating and stirring, dehydrating and condensing hydroxyl on the surface of Fe 3 O 4 with silanol hydroxyl, and generating an Fe 3 O 4 layer in situ to obtain a second solution; and S4, mixing the second solution with a solvent, a thixotropic agent, solder powder and soldering flux, and carrying out vacuum degassing and aging to obtain the solder paste.
  5. 5. The method for preparing the wear-resistant brazing paste according to claim 4, wherein in the step S1, the temperature of the hydrolysis reaction is 50-60 ℃, and the time of the hydrolysis reaction is 1-2h.
  6. 6. The method for preparing the wear-resistant brazing paste according to claim 4, wherein in the step S2, the heating temperature is 100-120 ℃ and the heating time is 2-4h.
  7. 7. The method for preparing the wear-resistant brazing paste according to claim 4, wherein in the step S3, the heating temperature is 100-120 ℃ and the heating time is 1-3h.
  8. 8. The method of preparing a wear-resistant solder paste according to claim 4, wherein in step S4, the mixing comprises the steps of adding the solvent and the thixotropic agent to the second solution, stirring at 100-150r/min for 0.5-1h, then adding the solder powder, stirring at 100-150r/min for 1-2h, then adding the soldering flux, and stirring at 60-100r/min for 0.5-1h.
  9. 9. A method of brazing, comprising the steps of: (1) Cleaning and pre-treating the substrate; (2) Coating the brazing paste on the surface of the matrix, and drying; (3) Carrying out induction heating on the coated substrate, preserving heat at the brazing temperature, and cooling to obtain a wear-resistant coating; Wherein the brazing paste is the wear-resistant brazing paste according to any one of claims 1 to 3 or the wear-resistant brazing paste prepared by the preparation method according to any one of claims 4 to 8.
  10. 10. A method of brazing as in claim 9, wherein at least one of the following characteristics is met: a. In the step (2), the coating thickness of the brazing paste is 1-3mm; b. in the step (3), the power of the induction heating is 15-45kW, and the frequency is 500-900kHz; c. In the step (3), the brazing filler metal powder in the brazing paste comprises nickel-based brazing filler metal powder, the brazing temperature is 1000-1280 ℃, and the heat preservation time is 4-8min.

Description

Wear-resistant brazing paste, preparation method thereof and brazing method Technical Field The invention relates to the technical field of heavy-duty part surface strengthening, in particular to wear-resistant brazing paste, a preparation method thereof and a brazing method. Background The existing wear-resistant brazing paste mostly adopts a physical mixed system of brazing powder and diamond hard phase, component dispersion is realized through mechanical stirring, and brazing heating modes are mostly high-temperature heating of a vacuum furnace. The scheme is widely applied to the surface strengthening of engineering equipment, but is limited by structural design and heating modes, and has a plurality of technical bottlenecks. Firstly, the density difference between diamond and solder is remarkable (for example, about 3.5g/cm 3 of diamond and about 8.2g/cm 3 of nickel-based solder), effective restraint is lacking in a physical mixed system, the diamond is unevenly distributed in the process of brazing, the uniformity of coating performance is poor, the local wear resistance is weak, and secondly, the diamond is easy to carbonize and oxidize and burn, especially when the diamond is used for nickel-based solder, the brazing temperature is as high as 1150-1280 ℃, and the burning condition is more serious. At present, some researches are performed on protecting diamond by adopting a single coupling agent, but the protection effect is limited, the reaction channel is difficult to block for a long time, and the distribution uniformity of the diamond is difficult to effectively improve. Therefore, the development of a novel brazing paste and brazing process realizes uniform dispersion of hard phases, and meanwhile, the protection of diamond effectively reduces the burning loss rate of the diamond, which is a key for improving the brazing strengthening effect of heavy-duty parts. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide wear-resistant brazing paste, a preparation method thereof and a brazing method, wherein Fe 3O4 is coated on the surface of diamond, so that the burning loss condition of the diamond is effectively improved, meanwhile, the magnetic property of hard phase particles is endowed, and the movement of the hard phase in a brazing filler metal molten pool is promoted to realize uniform dispersion by utilizing the electromagnetic force and eddy current effect generated in the induction magnetic field heating process, so that the wear resistance of a coating is effectively improved. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: An abrasion-resistant brazing paste comprises brazing filler metal powder, a hard phase, a solvent, a thixotropic agent and a soldering flux, wherein the hard phase comprises diamond and Fe 3O4 coated on at least part of the surface of the diamond. Preferably, the brazing paste comprises, by mass, 10-12 parts of diamond, 5-8 parts of Fe 3O4, 12-15 parts of a silane coupling agent, 48-60 parts of brazing powder, 5-7 parts of a solvent, 2-4 parts of a thixotropic agent, 7-10 parts of a soldering flux and 0.5-1 part of a silane hydrolysis agent; Wherein, si atoms in the silane coupling agent are connected with at least two alkoxy groups, the silane hydrolysis agent comprises water, and the diamond is diamond with hydroxyl groups on the surface. Preferably, the silane coupling agent comprises at least one of vinyl triethoxysilane, aminopropyl trimethoxysilane, gamma-mercaptopropyl trimethoxysilane, N-aminoethyl-3-aminopropyl methyl dimethoxy silane. Preferably, the solder powder comprises nickel-based solder powder and/or copper-based solder powder. Preferably, the solvent comprises at least one of glycerol, propylene glycol, diethylene glycol methyl ether, tripropylene glycol methyl ether. Preferably, the thixotropic agent comprises a polyamide wax and/or hydrogenated castor oil. Preferably, the soldering flux comprises borax and/or boric acid. Preferably, the diamond has an average particle size of 30 to 50 μm. Preferably, the average particle size of Fe 3O4 is 5-10nm. Preferably, the solder powder has a particle size of 200-300 mesh. A method of preparing the wear-resistant braze paste of any of the preceding embodiments, comprising the steps of: S1, adding a silane hydrolysis agent into a silane coupling agent for hydrolysis reaction, so that alkoxy on the silane coupling agent is converted into silanol hydroxyl to obtain hydrolysis liquid; s2, adding diamond into the hydrolysate, heating and stirring, and coating the hydrolyzed silane coupling agent on the surface of the diamond to form a protective film to obtain a first solution; S3, adding Fe 3O4 into the first solution, heating and stirring, dehydrating and condensing hydroxyl on the surface of Fe 3O4 with silanol hydroxyl, and generating an Fe 3O4 layer in situ to obtain a second solut