A Mo-Cu alloy preparation method based on surface coating technology and flame spraying technology

Abstract

The present invention provides a Mo-Cu alloy preparation method based on surface coating technology and flame spraying technology, comprising the following steps: S1: ammonium tetramolybdate powder and copper nitrate powder are mixed in mass ratio, added to ammonia and deionized water mixture and continuously stirred and heated; S2: the reaction product is washed with deionized water and separated, the reaction product is washed with anhydrous ethanol and heated and dried, and the reaction product powder after drying is subjected to a calcination experiment to prepare a Mo-Cu composite powder with a Mo coating layer; S3: the prepared Mo-Cu composite powder with a Mo coating layer is sprayed on the surface of the substrate by oxygen-acetylene flame spraying technology, and multi-layer spraying accumulation is performed; S4: the prepared Mo-Cu alloy is subjected to hydrogen reduction experiment and vacuum sintering experiment to prepare a high-density Mo-Cu alloy. The Mo-Cu alloy prepared by the present invention has a high density, can realize process parameter optimization and regulation of organization and performance, improve the interfacial bonding strength between particles and optimize control.

Description

Technical Field

[0001] The invention belongs to the field of electric contact materials, and in particular relates to a method for preparing a high-density Mo-Cu alloy. Background Art

[0002] With the continuous improvement and development of the State Grid's ultra-high voltage transmission network and the increasing proportion of renewable energy power generation, high-voltage transmission has gradually become the mainstream mode of long-distance transmission. Therefore, the service conditions of high-voltage electrical contact materials have become more demanding, and new requirements have been put forward for the density, uniformity of organization and performance, mechanical properties and thermoelectric properties of Mo-Cu alloy materials. As the "heart" of high-voltage transmission devices, Mo-Cu alloy electrical contact materials are mainly responsible for connecting and disconnecting high-voltage circuits. At present, the main cause of failure of high-voltage transmission devices is the failure of high-voltage electrical contacts. Once the electrical contact material fails, it will inevitably affect the normal transmission of high-voltage transmission lines. Therefore, the preparation of highly dense and excellent Mo-Cu electrical contact materials has far-reaching significance. The problem of high porosity in the preparation process of Mo-Cu electrical contact materials has always been a technical problem that needs to be solved urgently. In order to improve the density of Mo-Cu alloy and realize the regulation of Mo-Cu alloy structure and performance, Mo-Cu alloy is prepared by surface coating technology and flame spraying technology. It can not only improve the density of Mo-Cu alloy, but also realize the regulation of Mo-Cu alloy structure and performance. By controlling the composition ratio of Mo and Cu and the powder particle size, the service life of Mo-Cu alloy can be improved.

[0003] At present, the main preparation technology for Mo-Cu alloy is powder metallurgy, and its main steps are as follows: prepare Mo-Cu composite powder by mechanical alloying, use a press to mold, and sinter in a vacuum hot pressing sintering furnace to prepare Mo-Cu alloy. The Mo-Cu alloy prepared by powder metallurgy has a high porosity, poor uniformity of organizational composition, and is prone to component segregation and agglomeration. Relevant researchers at home and abroad have also conducted relevant research on Mo-Cu alloy and its composite powder preparation technology. Starting from the composite powder preparation technology, they explored the influence of different composite powder preparation technologies on the structure and properties of Mo-Cu alloy. However, Mo-Cu alloys prepared by powder metallurgy generally have problems such as low density. New Mo-Cu alloy preparation methods such as metal powder injection molding are still in their infancy and have not been able to achieve industrial mass production.

[0004] In view of the process drawbacks of the Mo-Cu alloy preparation method, the present invention proposes a Mo-Cu alloy preparation method based on surface coating technology and flame spraying technology. The present invention prepares a highly dense Mo-Cu alloy by optimizing and controlling the chemical-reduction solution ratio, spraying process, reduction process, and sintering process, which is of great significance for realizing the control of the Mo-Cu alloy structure and performance and improving the service life of the Mo-Cu alloy. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned existing Mo-Cu alloy preparation technology, the purpose of the present invention is to provide a Mo-Cu alloy preparation method based on surface coating technology and flame spraying technology. The Mo-Cu alloy has high density, uniform structure and performance, adjustable thermal expansion coefficient, and excellent electrical and thermal conductivity. This technology improves the density of the Mo-Cu alloy, realizes the optimization control of the structure and performance of the Mo-Cu alloy, and enables it to be widely used.

[0006] The present invention provides a method for preparing a Mo-Cu alloy based on surface coating technology and flame spraying technology. The proposed technical solution comprises the following steps:

[0007] S1: Mix ammonium tetramolybdate powder and copper nitrate powder according to a mass ratio, add into a mixture of ammonia water and deionized water, and continue stirring and heating;

[0008] S2: washing the reaction product with deionized water and separating it, washing the reaction product with anhydrous ethanol and heating and drying it to prepare a reaction product powder, and performing a calcination experiment on the dried reaction product powder to prepare a Mo-Cu composite powder with a Mo coating layer;

[0009] S3: grinding the substrate surface with sandpaper and performing sandblasting on the substrate surface, spraying the prepared Mo-Cu composite powder with a Mo coating layer on the substrate surface with an oxygen-acetylene flame spraying technique, and performing multi-layer spraying accumulation to prepare a Mo-Cu alloy;

[0010] S4: The prepared Mo-Cu alloy is subjected to a hydrogen reduction experiment and a vacuum sintering experiment to prepare a high-density Mo-Cu alloy.

[0011] Furthermore, in step S1, the mass ratio of ammonium tetramolybdate to copper nitrate is weighed according to the ratio of 30%-70% of the Cu content of the Mo-Cu alloy, the ammonia water is twice the amount of deionized water, the water bath heating temperature is 20-80°C, the stirring speed is 100-200 r / min, and the stirring time is 20-40 min.

[0012] Furthermore, in step S2, the drying temperature is 80-120° C., and the drying time is 2-4 hours.

[0013] Furthermore, in the calcination experiment in step S2, the calcination temperature is 240-600°C, the holding time is 1-2h, the heating rate is 2-5°C / min, and the cooling rate is 5-10°C / min.

[0014] Furthermore, in the step S3, the acetylene flow rate of the oxygen-acetylene flame spraying is 200-400 L / h, the oxygen flow rate is 100-200 L / h, the spraying distance is 20-50 mm, the spraying speed is 50-150 mm / s, the acetylene pressure is 0.1-0.2 MPa, the oxygen pressure is 0.4-0.8 MPa, the powder feeding amount of the Mo-Cu composite powder is 10 g / min, and the substrate preheating temperature is 600-700°C.

[0015] Furthermore, in the hydrogen reduction experiment in step S4, the hydrogen reduction temperature is 1050-1200°C, the holding time is 2-6h, the hydrogen flow rate is 0.5-1.5L / min, the heating rate is 5-10°C / min, and the cooling rate is 5-10°C / min.

[0016] Furthermore, the vacuum sintering experimental process of the Mo-Cu alloy in step S4 is as follows: the vacuum degree required in the vacuum hot pressing sintering furnace is 10 -2 -10 -6 Pa, sintering temperature 1150-1350℃, holding time 2-4h, heating rate 2-5℃ / min, cooling with the furnace.

[0017] Furthermore, the density of the Mo-Cu alloy is above 98%.

[0018] Furthermore, the substrate is 304 stainless steel.

[0019] Beneficial effects of the present invention:

[0020] (1) The composite powder with a Mo coating layer prepared by the present invention can be used to prepare Mo-Cu composite powders with different ratios by adjusting the ratio of powder raw materials. In addition, the growth of the Cu phase can be inhibited during the preparation of the Mo-Cu alloy, and the two phases can be evenly distributed without agglomeration and segregation.

[0021] (2) The present invention prepares Mo-Cu alloy by oxygen-acetylene flame spraying technology, and can achieve high-density Mo-Cu alloy preparation by adjusting various process parameters. After flame spraying technology, a high-density Mo-Cu alloy with uniform microstructure can be obtained, and the interface bonding between particles has high strength.

[0022] (3) The present invention adjusts the structure and performance of the composite powder with a Mo coating layer and the Mo-Cu alloy through low-temperature calcination, hydrogen reduction, and vacuum sintering experiments, so that the obtained composite powder with a Mo coating layer has better powder fluidity and eliminates powder agglomeration, and adjusts the interface bonding between Mo-Cu alloy particles and the structure and performance regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic diagram of the operation flow of a method for preparing a Mo-Cu alloy based on surface coating technology and flame spraying technology. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Embodiment 1:

[0026] like Figure 1 As shown, in this embodiment, a composite powder having a Mo coating layer is prepared by surface coating technology, and a high-density Mo-Cu alloy is prepared on the surface of a stainless steel substrate by oxygen-acetylene flame spraying technology.

[0027] In this embodiment, the material of the substrate is 304 stainless steel.

[0028] In this embodiment, the prepared Mo-Cu composite powder with a Mo coating layer is prepared by a chemical method.

[0029] In this embodiment, the prepared high-density Mo-Cu alloy is prepared by oxygen-acetylene flame spraying, and has excellent interface bonding strength.

[0030] Combination Figure 1 , a Mo-Cu alloy preparation method based on surface coating technology and flame spraying technology, comprising the following steps:

[0031] Step 1, weigh and mix ammonium tetramolybdate and copper nitrate in a mass ratio of 30%-70% of the Cu content of the Mo-Cu alloy, add them into a mixture of ammonia water and deionized water (2:1) and continue stirring and heating, the water bath heating temperature is 20-80°C, the stirring speed is 100-200r / min, and the stirring time is 20-40min;

[0032] Step 2: washing the reaction product with deionized water and separating it, washing the reaction product with anhydrous ethanol and heating and drying it at a drying temperature of 80-120° C. for 2-4 hours;

[0033] Step 3, a calcination experiment is performed on the reaction product powder, the calcination temperature is 240-600°C, the holding time is 1-2h, the heating rate is 2-5°C / min, and the cooling rate is 5-10°C / min, to prepare a Mo-Cu composite powder with a Mo coating layer;

[0034] Step 4: grinding the surface of the substrate with sandpaper and performing sandblasting on the surface of the substrate;

[0035] Step 5, Mo-Cu alloy is prepared by oxygen-acetylene flame spraying technology, acetylene flow rate is 200-400L / h, oxygen flow rate is 100-200L / h, spraying distance is 20-50mm, spraying speed is 50-150mm / s, acetylene pressure is 0.1-0.2MPa, oxygen pressure is 0.4-0.8MPa, powder feeding amount of Mo-Cu composite powder is 10g / min, and substrate preheating temperature is 600-700°C;

[0036] Step 6: A tubular atmosphere furnace is used for hydrogen reduction experiment, with a heating temperature of 1050-1200°C, a holding time of 2-6h, a hydrogen flow rate of 0.5-1.5L / min, a heating rate of 5-10°C / min, and a cooling rate of 5-10°C / min;

[0037] Step 7: Use a vacuum hot pressing sintering furnace to conduct a high temperature sintering experiment. The vacuum degree required for the vacuum hot pressing sintering furnace is 10 -2 -10 -6 Pa, sintering temperature 1150-1350℃, holding time 2-4h, heating rate 2-5℃ / min, cooling with the furnace.

[0038] The present invention provides a relatively clear and complete description of the technical solution through examples, but does not limit the present invention. For professionals in the field, the preparation method of the Mo-Cu composite powder by adjusting the designed parameters (such as by changing the calcination process, flame spraying process, hydrogen reduction and high-temperature sintering process) and changing the ratio should fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology, characterized in that: The following steps are involved: S1: Mix ammonium tetramolybdate powder and copper nitrate powder according to a mass ratio, add into a mixture of ammonia water and deionized water, and continue stirring and heating; S2: washing the reaction product with deionized water and separating it, washing the reaction product with anhydrous ethanol and heating and drying it to prepare a reaction product powder, and performing a calcination experiment on the dried reaction product powder to prepare a Mo-Cu composite powder with a Mo coating layer; S3: grinding the substrate surface with sandpaper and performing sandblasting on the substrate surface, spraying the prepared Mo-Cu composite powder with a Mo coating layer on the substrate surface with an oxygen-acetylene flame spraying technique, and performing multi-layer spraying accumulation to prepare a Mo-Cu alloy; S4: The prepared Mo-Cu alloy is subjected to a hydrogen reduction experiment and a vacuum sintering experiment to prepare a high-density Mo-Cu alloy.

2. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: In step S1, the mass ratio of ammonium tetramolybdate and copper nitrate is weighed according to the ratio of 30%-70% of the Cu content of the Mo-Cu alloy, the amount of ammonia water is twice that of deionized water, the water bath heating temperature is 20-80°C, the stirring speed is 100-200r / min, and the stirring time is 20-40min.

3. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: In step S2, the drying temperature is 80-120° C. and the drying time is 2-4 hours.

4. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: The calcination temperature of the calcination experiment in step S2 is 240-600°C, the holding time is 1-2h, the heating rate is 2-5°C / min, and the cooling rate is 5-10°C / min.

5. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: In the step S3, the acetylene flow rate of the oxygen-acetylene flame spraying is 200-400 L / h, the oxygen flow rate is 100-200 L / h, the spraying distance is 20-50 mm, the spraying speed is 50-150 mm / s, the acetylene pressure is 0.1-0.2 MPa, the oxygen pressure is 0.4-0.8 MPa, the powder feeding amount of the Mo-Cu composite powder is 10 g / min, and the substrate preheating temperature is 600-700°C.

6. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: The hydrogen reduction temperature of the hydrogen reduction experiment in step S4 is 1050-1200° C., the holding time is 2-6 hours, the hydrogen flow rate is 0.5-1.5 L / min, the heating rate is 5-10° C. / min, and the cooling rate is 5-10° C. / min.

7. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: The experimental process of vacuum sintering of Mo-Cu alloy in step S4 is as follows: the vacuum degree required in the vacuum hot pressing sintering furnace is 10 -2 -10 -6 Pa, sintering temperature 1150-1350℃, holding time 2-4h, heating rate 2-5℃ / min, cooling with the furnace.

8. The method for preparing Mo-Cu alloy based on surface coating technology and flame spraying technology according to claim 1, characterized in that: The density of the Mo-Cu alloy is above 98%.

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