CN111979536A - Hydrophobic rare earth doped copper-silver alloy-carbon nano composite coating material for electrical contact and preparation method thereof - Google Patents
Hydrophobic rare earth doped copper-silver alloy-carbon nano composite coating material for electrical contact and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a hydrophobic rare earth doped copper-silver alloy-carbon nano composite coating material for an electrical contact and a preparation method thereof. Uniformly mixing the required copper-silver alloy powder, carbon powder (graphite and graphene) and rare earth powder raw materials, then adopting copper with certain roughness as a matrix, and utilizing high-speed mixed powder generated by a cold spraying technology to impact the matrix to deposit the rare earth-doped copper-silver alloy-carbon nano composite coating material; after the preparation of the initial cold spraying coating is finished, rapidly scanning the surface of the coating by using a laser according to different parameters to obtain the rare earth doped copper-silver-carbon nano composite coating material for the electrical contact. The rare earth doped copper-silver alloy-carbon nano composite coating material for the electrical contact prepared by the invention has excellent hydrophobic property, wear resistance, electrochemical corrosion resistance and arc erosion resistance, and can effectively improve the adaptability and the service performance of the silver-based electrical contact material in an outdoor humid environment.
Description
Technical Field
The invention relates to a hydrophobic rare earth doped copper-silver alloy-carbon nano composite coating material for an electrical contact and a preparation method thereof, belonging to the field of coating materials.
Background
The electrical contact material is an indispensable contact element in a load-bearing current conversion device, has been developed for more than one hundred years, mainly passes through three stages of electrical contact metal materials, electrical contact alloy materials and electrical contact composite materials, and is applied to various light and heavy-load high-low voltage electrical appliances, household electrical appliances, automobile electrical appliances and aerospace electrical appliances. The silver-based electrical contact material has the characteristics of good wear resistance, good fusion welding resistance, good conductivity and low contact resistance as the electrical contact material which is most widely researched and applied, and the silver-based electrical contact material is almost completely adopted by electric appliances with large quantity, such as a circuit breaker and a contactor. At present, the mature silver-based electrical contact materials can be mainly classified into 4 series, such as Ag/C series, Ag/WC series, Ag/Ni series and Ag/MeO series.
The production of Ag/C series contact materials is mainly based on the good complementation of metal Ag and graphite materials in performance, the common electrical contact is required to have excellent electro-physical properties, thermodynamic properties, mechanical properties and chemical properties, Ag metal has good electric conduction and heat conduction properties, good plasticity and high corrosion resistance, but the thermophysical properties are not high, and graphite has high thermophysical properties and oxides have volatility or conductivity. Carbon generates reducing atmosphere under the action of electric arc, thereby preventing carbide and metal from being oxidized, reducing contact resistance, enhancing loss resistance, reducing splashing, improving the performances of loss resistance, low temperature rise and the like, Ag has smaller affinity with oxygen, and the oxidized product has smaller resistivity which can be decomposed at 200 ℃, thus providing lower contact resistance for electrical contact materials and realizing good metal piece contact. Therefore, the Ag/C composite electrical contact material obtained by adding a certain amount of graphite powder additive phase into the Ag matrix has the characteristics of good electrical conductivity, low contact resistance, good fusion welding resistance, particularly good lubricating property, and has particular application advantages on parts needing sliding contact. Research shows that the contact characteristic of Ag/C material has great relation with the distribution of carbon additive phase in silver matrix and the surface composition and shape of the electric contact material. Because the carbon powder has small specific gravity, the carbon powder is difficult to be uniformly manufactured by a powder metallurgy method; the silver-carbon composite material produced by adopting a sintering extrusion method can reach more than 99.9 percent of theoretical density, and various performances are obviously improved; the compression and sintering methods are also adopted to prepare the nickel-added Ag/C contact, however, the processes all need a large amount of metal silver, and the cost is high.
The comprehensive use performance (such as fusion welding resistance, arc burning resistance, temperature rise and corrosion rate) of the electrical contact material is influenced by the components, tissues, microstructures and preparation process of the material, but the existing method for preparing the silver-based graphite electrical contact material still has the problems of complex steps, long time consumption, poor dispersibility, serious pollution, high consumption, and poor corrosion resistance and arc erosion resistance of the material.
Disclosure of Invention
The invention aims to compensate the defects of the prior art and provides a hydrophobic rare earth doped copper-silver alloy-carbon nano composite coating material for an electrical contact and a preparation method thereof.
The scheme adopted by the invention for solving the technical problems is as follows:
a preparation method of a rare earth doped copper-silver alloy-carbon nano composite coating for an electrical contact comprises the following steps:
(1) uniformly mixing and stirring copper-silver alloy powder, rare earth powder and carbon powder to obtain mixed powder;
(2) depositing the mixed powder obtained in the step (1) on a substrate plate by adopting a cold spraying process to obtain an initial coating;
(3) and (3) carrying out laser scanning post-treatment on the surface of the initial coating obtained in the step (2) to obtain the rare earth doped copper-silver alloy-carbon nano composite coating.
Preferably, the proportion of the copper-silver alloy powder, the carbon powder and the rare earth powder in the mixed powder in the step (1) is 75-100%, 0-20% and 0-5% in sequence.
Preferably, the size of the copper-silver alloy powder in the step (1) is 10-70 microns, and the weight proportion of silver in the copper-silver alloy is 10% -100%.
Preferably, the carbon powder is graphite and graphene two-phase mixed powder, the size of the graphite powder is 10-50 microns, and the number of graphene layers is 1-20; the content of graphite in the mixed powder obtained in the step (1) is 0-18 wt.%, and the content of graphene is 0-2 wt.%.
Preferably, the rare earth is a mixed phase of yttrium and strontium, and the weight ratio of yttrium to strontium in the rare earth is 1: 1, the particle size of the rare earth powder is 10-50 microns, and the stirring time of the mixed powder obtained in the step (1) is controlled to be 5-20 min.
Preferably, the cold spraying process in the step (2) has a heating temperature of 700-.
Preferably, the laser scanning post-treatment in the step (3) has a laser power of 120-.
Preferably, the base plate material is copper, and the roughness Ra of the copper base is 0.5-50 micrometers.
Preferably, the surface roughness Ra of the coating obtained in the step (3) is 10-30 microns, and the contact angle of the surface and water is in the range of 100-160 degrees.
The invention also aims to provide a rare earth doped copper-silver alloy-carbon nano composite coating material for an electrical contact, which is prepared by adopting the method.
In order to improve the performance of the electrical contact, the invention adopts a plurality of innovative technologies, firstly, the copper-silver alloy is adopted to replace the existing pure silver, and the copper-silver alloy is taken as one of excellent conductor materials, so that the copper-silver alloy can be widely applied to the industrial fields of aerospace, microelectronics, rail transit, mechanical manufacturing and the like. Compared with pure silver, the addition of copper makes the solid solution strengthening effect in the material obvious. The strength and hardness of the material can be greatly improved as a result of solid solution strengthening, and the wear resistance and oxidation resistance of the material can be improved; secondly, the addition of the rare earth can refine the grain size of the coating and eliminate defects, so that the conductivity and the density of the coating are improved; and thirdly, combining and doping graphite and graphene into the silver coating to improve the electric conduction, the heat conduction and the arc erosion resistance of the silver coating. The preparation technology adopts the combination of the environment-friendly cold spray deposition technology and the laser surface scanning modification technology to prepare the silver-carbon composite electrical contact coating material, the research on the electrical contact material prepared by the cold spray technology is less at present, and the research on the laser surface scanning modification as the post-treatment means of the rare earth doped copper-silver alloy-carbon nano composite coating material is not found, so the preparation method has important innovation and application value.
The cold spraying technology has two main functions, namely, the uniform and compact rare earth doped copper-silver alloy-carbon nano composite coating material is quickly obtained, and the characteristic that the cold spraying technology generates deformation and film formation by high-speed impact at low temperature is utilized to maintain the solid state of the rare earth doped copper-silver alloy-carbon nano composite coating material and avoid a metallurgical process so as to ensure the characteristic of original material performance. After the preparation of the original rare earth doped copper-silver alloy-carbon nano composite coating material is finished, the surface is processed by utilizing a laser surface scanning modification method, the laser has high energy density, the action range is in the surface area of a sample, the internal cold spraying structure is not influenced, the surface of the processed contact material can be rapidly melted and solidified, and the process enables the surface of the rare earth doped copper-silver alloy-carbon nano composite coating material to form a new microstructure and changes the microhardness of the surface. Therefore, the rare earth doped copper-silver alloy-carbon nano composite coating material prepared by the method integrates the common advantages of two technologies: the cold spraying technology has the characteristics of environmental protection, rapidness, non-melting property and high utilization rate, and the laser post-treatment has the characteristics of rapidness, high efficiency and accuracy. The rare earth doped copper-silver alloy-carbon nano composite coating electric contact material has a complex surface, and the electric arc bedding resistance, the hydrophobic property and the electrochemical corrosion resistance of the material are improved, so that the material can be widely applied.
Therefore, the preparation method of the green environment-friendly silver-carbon composite coating material provided by the invention has the following advantages and positive effects:
1) the copper-silver alloy is adopted to replace the existing pure silver coating material, so that the hardness, strength, toughness and wear resistance of the coating are greatly improved, the coating has better contact impact fatigue resistance, and the environmental adaptability of the coating is improved;
2) the graphite and graphene dual-phase material is added into the copper-silver alloy raw material powder for the first time for reinforcement, so that the fusion welding resistance of the contact can be obviously improved, the generation of oxides can be prevented to a certain extent, meanwhile, the electric conductivity and the heat conductivity of the coating can be improved by using the graphene, the contact resistance is reduced, and the service performance of the contact is improved;
3) the doping of the rare earth elements can reduce the grain size of the coating and improve the compactness of the coating, so that the coating has better tolerance performance at high temperature;
4) the rare earth doped copper-silver alloy-carbon nano composite coating is prepared by adopting a cold spraying method for the first time, melting behavior cannot occur in the whole process, the purity of powder components is kept, and the obtained finished product has uniform components and controllable thickness and can be quickly prepared in a large area.
5) By utilizing the characteristic of rapid fusing of the laser scanning modification technology, the surface microstructure can be complicated under the combined action with the surface after cold spraying, and the electrochemical corrosion resistance, the electric arc erosion resistance and the hydrophobic property of the contact are improved.
6) The technical process route designed and provided by the invention has the advantages of simple steps, short production period, low economic cost, suitability for rapid mass production and good industrial application prospect.
Drawings
FIG. 1 is a surface view of a cold-sprayed rare earth-doped Cu-Ag alloy-carbon nanocomposite coating material obtained in example 6 of the present invention;
FIG. 2 is a cross-sectional view of a cold-sprayed rare earth-doped Cu-Ag alloy-carbon nanocomposite coating material obtained in example 6 of the present invention;
FIG. 3 is a schematic view of laser thermal processing according to the present invention;
FIG. 4 is a surface view of a rare earth doped Cu-Ag alloy-carbon nanocomposite coating electrical contact sample obtained in examples 1-6 of the present invention, wherein (a) - (f) correspond to examples 1-6, respectively.
Detailed Description
The following examples are provided to further illustrate the present invention for better understanding, but the present invention is not limited to the following examples.
Example 1:
(1) preparing a copper matrix with the roughness Ra of 0.5 micron for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.9, and the total content of copper-silver alloy is 100 wt.%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 10 microns, the particle size distribution of the graphite powder particles is 10 microns, the number of graphene layers is 1, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 5 minutes; the specific proportion of the copper-silver alloy powder and the carbon powder is as follows: the ratio of the carbon powder is 0 wt.%, the content of graphite in the carbon powder is 0 wt.%, and the content of graphene is 0 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, and the total addition amount of the rare earth is 0%. The balance of copper-silver alloy powder.
(3) Placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 700 ℃, the working pressure is 2.5MPa, and the distance from the spray gun port to a sample is controlled at 50 mm; loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on a copper base plate under the condition, wherein the thickness is controlled to be 30 microns;
(4) and carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 120W, the scanning speed is 2000mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the obtained coating is 10 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 100 degrees, the binding force of the coating is 40MPa, the microhardness is 0.9GPa, and the density of the coating is 94 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.0E-06. omega. cm, and the mass loss after 10000 arc erosions was 2.55 mg.
Example 2:
(1) preparing a copper matrix with the roughness Ra of 50 microns for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.8, and the total content of copper-silver alloy is 75 wt.%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the copper-silver alloy powder particles is 70 micrometers, the particle size distribution of the graphite powder particles is 50 micrometers, the number of graphene layers is 20, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 20 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 20 wt.%, the graphite content in the carbon powder is 18 wt.%, and the graphene content is 2 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 5%, wherein the weight ratio of yttrium to strontium is 1: 1, the particle size of the powder is 50 microns;
(3) placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 1000 ℃, the working pressure is 5MPa, and the distance from the spray gun port to a sample is controlled at 300 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper base plate under the condition, wherein the thickness is controlled to be 3000 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 150W, the scanning speed is 6000mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the scanned coating is 30 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 160 degrees, the binding force of the coating is 50MPa, the microhardness is 1.1GPa, and the density of the coating is 95 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.4E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.8 mg.
Example 3:
(1) preparing a copper matrix for the electrical contacts with different roughness to be deposited, wherein the roughness Ra of the copper matrix is 0.5-50 microns, and then ultrasonically cleaning the matrix in acetone and alcohol, and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.7, and the total content of copper-silver alloy is 80 wt%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of copper silver powder particles is 50 microns, the particle size distribution of graphite powder particles is 40 microns, the number of graphene layers is 10, silver powder and carbon powder are uniformly mixed through mechanical stirring, and the stirring time is controlled to be 10 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 17 wt.%, the graphite content in the carbon powder is 16 wt.%, and the graphene content is 1 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 3%, wherein the weight ratio of the yttrium to the strontium is 1: 1, the particle size of the powder is 40 microns;
(3) placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 800 ℃, the working pressure is 4MPa, and the distance from the spray gun port to a sample is controlled to be 200 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper substrate plate under the condition, wherein the thickness is controlled to be 1000 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 140W, the scanning speed is 3000mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 20 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 150 degrees, the binding force of the coating is 60MPa, the microhardness is 1.3GPa, and the density of the coating is 96 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.4E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.83 mg.
Example 4:
(1) preparing a copper matrix with the roughness Ra of 30 microns for the electrical contacts with different degrees of roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.6, and the total content of copper-silver alloy is 80 wt%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the copper-silver powder particles is 50 microns, the particle size distribution of the graphite powder particles is 40 microns, the number of the graphene layers is 15, the copper-silver alloy, the rare earth powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 10 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 16 wt.%, the graphite content in the carbon powder is 15 wt.%, and the graphene content is 1 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 4%, wherein the weight ratio of yttrium to strontium is 1: 1, the particle size of the powder is 10-50 microns.
(3) Placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 800 ℃, the working pressure is 3MPa, and the distance from the spray gun port to a sample is controlled at 100 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper base plate under the condition, wherein the thickness is controlled to be 1500 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 130W, the scanning speed is 2500mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 20 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 150 degrees, the binding force of the coating is 70MPa, the microhardness is 1.5GPa, and the density of the coating is 97 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.5E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.82 mg.
Example 5:
(1) preparing a copper matrix with the roughness Ra of 30 microns for the electrical contacts with different degrees of roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.5, and the total content of copper-silver alloy is 88 wt.%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 20 microns, the particle size distribution of the graphite powder particles is 20 microns, the number of graphene layers is 10, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 10 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 11 wt.%, the graphite content in the carbon powder is 10 wt.%, and the graphene content is 1 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 1%, wherein the weight ratio of yttrium to strontium is 1: 1, the particle size of the powder is 10 microns;
(3) placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 900 ℃, the working pressure is 3MPa, and the distance from the spray gun port to a sample is controlled to be 80 mm; the rare earth doped copper-silver alloy-carbon nano composite coating powder is filled into a powder feeder of a cold spraying system, and a layer of rare earth doped copper-silver alloy-carbon nano composite coating material is deposited on a copper substrate plate under the condition, wherein the thickness is controlled to be 1600 micrometers.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 120W, the scanning speed is 2500mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 25 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 150 degrees, the binding force of the coating is 80MPa, the microhardness is 1.9GPa, and the density of the coating is 98 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.5E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.87 mg.
Example 6:
(1) preparing a copper matrix with the roughness Ra of 45 microns for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.5, and the total content of copper-silver alloy is 81 wt%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 65 micrometers, the particle size distribution of the graphite powder particles is 45 micrometers, the number of graphene layers is 16, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 15 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 18 wt.%, the graphite content in the carbon powder is 17 wt.%, and the graphene content is 1 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 1%, wherein the weight ratio of yttrium to strontium is 1: 1, the particle size of the powder is 10 microns;
(3) placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 700 ℃, the working pressure is 3.5MPa, and the distance from the spray gun port to a sample is controlled at 60 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper base plate under the condition, wherein the thickness is controlled to be 1500 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 140W, the scanning speed is 2800mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 18 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 135 degrees, the binding force of the coating is 80MPa, the microhardness is 1.9GPa, and the density of the coating is 99%.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.5E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.85 mg.
Example 7
(1) Preparing a copper matrix with the roughness Ra of 0.5 micron for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped pure silver composite coating comprises copper-silver alloy powder, wherein the copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 1, and the total content of copper-silver alloy is 100 wt.%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 10 microns, the particle size distribution of the graphite powder particles is 10 microns, the number of graphene layers is 1, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 5 minutes; the specific proportion of the copper-silver alloy powder and the carbon powder is as follows: the ratio of the carbon powder is 0 wt.%, the content of graphite in the carbon powder is 0 wt.%, and the content of graphene is 0 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, and the total addition amount of the rare earth is 0%. The balance of copper-silver alloy powder.
(3) Placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 700 ℃, the working pressure is 2.5MPa, and the distance from the spray gun port to a sample is controlled at 50 mm; loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on a copper base plate under the condition, wherein the thickness is controlled to be 30 microns;
(4) and carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 120W, the scanning speed is 2000mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the obtained coating is 10 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 120 degrees, the binding force of the coating is 50MPa, the microhardness is 0.7GPa, and the density of the coating is 99 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 1.9E-06. omega. cm, and the mass loss after 10000 arc erosions was 2.65 mg.
Example 8
(1) Preparing a copper matrix with the roughness Ra of 45 microns for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight ratio of silver is 1, and the total content of copper-silver alloy is 81 wt%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 65 micrometers, the particle size distribution of the graphite powder particles is 45 micrometers, the number of graphene layers is 16, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 15 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 18 wt.%, the graphite content in the carbon powder is 17 wt.%, and the graphene content is 1 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 1%, wherein the weight ratio of yttrium to strontium is 1: 1, the particle size of the powder is 10 microns;
(3) placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 700 ℃, the working pressure is 3.5MPa, and the distance from the spray gun port to a sample is controlled at 60 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper base plate under the condition, wherein the thickness is controlled to be 1500 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 140W, the scanning speed is 2800mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 18 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 130 degrees, the binding force of the coating is 70MPa, the microhardness is 0.7GPa, and the density of the coating is 99 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.3E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.95 mg.
Example 9
(1) Preparing a copper matrix with the roughness Ra of 45 microns for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.5, and the total content of copper-silver alloy is 82 wt.%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 65 micrometers, the particle size distribution of the graphite powder particles is 45 micrometers, the number of graphene layers is 16, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 15 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 18 wt.%, the graphite content in the carbon powder is 17 wt.%, and the graphene content is 1 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, and the total addition amount of the rare earth is 0%.
(3) Placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 700 ℃, the working pressure is 3.5MPa, and the distance from the spray gun port to a sample is controlled at 60 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper base plate under the condition, wherein the thickness is controlled to be 1500 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 140W, the scanning speed is 2800mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 20 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 135 degrees, the binding force of the coating is 70MPa, the microhardness is 1.9GPa, and the density of the coating is 98 percent.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.5E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.9 mg.
Example 10
(1) Preparing a copper matrix with the roughness Ra of 45 microns for the electrical contacts with different roughness to be deposited, and then ultrasonically cleaning the matrix in acetone and alcohol and drying the matrix in a nitrogen atmosphere for later use.
(2) The rare earth doped copper-silver alloy-carbon nano composite coating is characterized in that copper-silver alloy powder is high-purity powder with the purity of 99.9%, the weight proportion of silver is 0.5, and the total content of copper-silver alloy is 81 wt%; the carbon powder is graphite and graphene biphase mixed powder. The particle size of the silver powder particles is 65 micrometers, the particle size distribution of the graphite powder particles is 45 micrometers, the number of graphene layers is 16, the silver powder and the carbon powder are uniformly mixed by mechanical stirring, and the stirring time is controlled to be 15 minutes; the specific proportion of the silver powder and the carbon powder is as follows: the carbon powder accounts for 18 wt.%, the graphite content in the carbon powder is 18 wt.%, and the graphene content is 0 wt.%. The rare earth phase is a mixed phase of yttrium and strontium, the total addition amount of the rare earth is 1%, wherein the weight ratio of yttrium to strontium is 1: 1, the particle size of the powder is 10 microns;
(3) placing the prepared copper matrix in front of a cold spray gun port, wherein the gas heating temperature is 700 ℃, the working pressure is 3.5MPa, and the distance from the spray gun port to a sample is controlled at 60 mm; and (3) loading the rare earth doped copper-silver alloy-carbon nano composite coating powder into a powder feeder of a cold spraying system, and depositing a layer of rare earth doped copper-silver alloy-carbon nano composite coating material on the copper base plate under the condition, wherein the thickness is controlled to be 1500 microns.
(4) And carrying out laser scanning post-treatment on the sprayed composite copper plate, wherein the laser power is 140W, the scanning speed is 2800mm/min, and the atmosphere is vacuum or atmosphere. The surface roughness Ra of the coating obtained after scanning is 18 micrometers, the contact angle range of the rare earth doped copper-silver alloy-carbon nano composite coating and water is 135 degrees, the binding force of the coating is 80MPa, the microhardness is 1.9GPa, and the density of the coating is 99%.
(5) And obtaining the rare earth doped copper-silver alloy-carbon nano composite coating electric contact after the preparation is finished. The resistivity was measured to be 2.5E-06. omega. cm, and the mass loss after 10000 arc erosions was 1.92 mg.
Fig. 1 is a surface view of a cold-sprayed rare earth-doped copper-silver alloy-carbon nanocomposite coating material obtained in example 6 of the present invention, and it can be seen from the surface view that there is significant particle deformation and the surface is relatively rough, but there are no defects on the surface of the coating after cold spraying.
FIG. 2 is a cross-sectional view of the cold-sprayed rare earth-doped Cu-Ag alloy-C nanocomposite coating obtained in example 6 of the present invention, from which it can be seen that the coating is dense and has good bonding force with the substrate.
Fig. 3 is a schematic diagram of laser surface scanning modification post-treatment of the rare earth doped copper-silver alloy-carbon nano composite coating material of the invention, and it can be seen from the diagram that the energy of the laser beam is concentrated and acts on the surface region of the sample to change the surface state of the sample.
Fig. 4 is a surface view of a contact sample after laser treatment of the rare earth-doped copper-silver alloy-carbon nanocomposite coating material obtained in embodiments 1 to 6 of the present invention, and it can be seen from the surface view that the state of the sample is obviously different from the state after cold spraying, which is beneficial to improving the hydrophobicity, electrochemical corrosion resistance and arc corrosion resistance of the electrical contact material.
The materials and the process used in the invention are not polluted completely, the uniformity of the phase distribution in the electrical contact material is ensured, the surface appearance of the material after cold spraying can be changed to a great extent by the laser surface scanning modification technology, and a surface which is completely different from the surface formed by the conventional heat treatment method is obtained, so that the good performance of the electrical contact material is obtained.
According to the technical scheme, the material disclosed by the invention comprehensively utilizes two strengthening effects, namely the strengthening of the rare earth, and the oxidation resistance of the coating is improved by mainly utilizing the fine-grain strengthening effect and the densification effect of the rare earth; secondly, graphite and graphene are reinforced in a two-phase composite mode, so that the temperature resistance and electric arc resistance of the coating are improved, and the electric conduction and heat conduction performance of the coating are also greatly improved; the method has great advantages for materials with good plasticity, can obtain compact coatings, and can obtain samples with any shape and size. The laser post-treatment can provide more complex surface micro-morphology and stress hardness state for the coating surface after cold spraying, can effectively influence the hydrophilic and hydrophobic properties of the material and the behavior of the material in arc erosion, obtains the rare earth doped copper-silver-carbon nano composite coating material with both hydrophobicity and excellent electrochemical resistance and arc erosion resistance, and has application advantages in outdoor humid environment.
While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims (10)
1. A preparation method of a rare earth doped copper-silver alloy-carbon nano composite coating for an electrical contact is characterized by comprising the following steps:
(1) uniformly mixing and stirring copper-silver alloy powder, rare earth powder and carbon powder to obtain mixed powder;
(2) depositing the mixed powder obtained in the step (1) on a substrate plate by adopting a cold spraying process to obtain an initial coating;
(3) and (3) carrying out laser scanning post-treatment on the surface of the initial coating obtained in the step (2) to obtain the rare earth doped copper-silver alloy-carbon nano composite coating.
2. The preparation method according to claim 1, wherein the proportions of the copper-silver alloy powder, the carbon powder and the rare earth powder in the mixed powder in the step (1) are 75-100%, 0-20% and 0-5% in sequence.
3. The preparation method according to claim 1, wherein the size of the copper-silver alloy powder in the step (1) is 10-70 microns, and the weight proportion of silver in the copper-silver alloy is 10-100%.
4. The preparation method according to claim 1, wherein the carbon powder is a graphite and graphene two-phase mixed powder, the size of the graphite powder is 10-50 microns, and the number of graphene layers is 1-20; the content of graphite in the mixed powder obtained in the step (1) is 0-18 wt.%, and the content of graphene is 0-2 wt.%.
5. The preparation method according to claim 1, wherein the rare earth is a mixed phase of yttrium and strontium, and the weight ratio of yttrium to strontium in the rare earth is 1: 1, the particle size of the rare earth powder is 10-50 microns, and the stirring time of the mixed powder obtained in the step (1) is controlled to be 5-20 min.
6. The method as claimed in claim 1, wherein the cold spraying process in step (2) has a heating temperature of 700-.
7. The method as claimed in claim 1, wherein the laser scanning in step (3) is post-processed, the laser power is 120-.
8. The method according to claim 1, wherein the base plate material is copper, and the copper base has a roughness Ra of 0.5 to 50 μm.
9. The method as claimed in claim 1, wherein the coating obtained in step (3) has a surface roughness Ra of 10-30 μm and a contact angle between the surface and water in the range of 100-160 °.
10. A rare earth doped copper-silver alloy-carbon nano composite coating material for an electrical contact, which is characterized by being prepared by the method of any one of claims 1 to 9.
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