CN111663159A - Preparation method of wear-resistant silicon carbide doped composite coating - Google Patents

Abstract

The invention discloses a preparation method of a wear-resistant silicon carbide doped composite coating, which is characterized in that, a brass substrate is put into acetone, and ultrasonically cleaned; the substrate is degreasing by chemical method, and then the substrate is cleaned Soak in hydrochloric acid solution for pickling activation to remove oil stains on the surface of the substrate; electroplating a layer of Cr-SiC-PTFE on the brass substrate to obtain a Cr-SiC-PTFE high wear-resistant composite coating, the obtained composite coating The friction coefficient of the coating is 0.34, and the hardness reaches the maximum value of 16.5GPa. The coating has high hardness and good wear resistance, and can be used as a protective coating for friction and wear-resistant workpieces. The method of the invention has the advantages of simple process, high deposition speed, low cost and good bonding strength.

Description

A kind of preparation method of wear-resistant silicon carbide doped composite coating

technical field

The invention relates to a metal surface modified lubricating coating, in particular to a preparation method of a wear-resistant silicon carbide doped composite coating, belonging to the technical field of materials.

Background technique

Electroplating is a surface treatment technology of surface modification. Different coatings are applied to the surface of materials to meet different performance requirements. Therefore, electroplating has been widely used in various fields of industrial production and scientific research. The chromium plating layer obtained by electroplating has good wear resistance, hardness and corrosion resistance, and it can be used not only for decorative plating, but also for functional plating in large quantities. The traditional chrome plating is to use hexavalent chromium plating solution, which is very toxic, about 100 times that of trivalent chromium. If the content of hexavalent chromium in water exceeds 0.1mg/L, it will be poisoned. In order to replace the hexavalent chromium electroplating, people have carried out many researches, among which the trivalent chromium to replace the hexavalent chromium electroplating is the main, and the most promising. The electroplating of trivalent chromium sulfate bath coating has made great progress in recent years because of its low pollution and high current efficiency.

In the field of research, a lot of research has been done on the preparation process of trivalent chromium composite coatings. In 1981, Caning in the United Kingdom developed the sulfate trivalent chromium double-tank electroplating process. In 1998, Ibrahim et al. invented the thick chromium plating process of trivalent chromium using urea as a complexing agent. In my country, mainly represented by Harbin Institute of Technology, the acetate system and formate system have been studied, and small-scale production applications have been obtained. In the 1990s, Central South University of Technology and Guangzhou Erqing Institute carried out research on trivalent chromium sulfate electroplating and titanium-based anodes. In the 20th century, Beijing Lanlijiamei Chemical Technology Center invented a BSC12 type trivalent chromium hard chromium plating solution, which has good stability and solves the problem of poor adhesion between the coating and the substrate and the existing trivalent chromium. The electroplating technology cannot obtain a thick coating, but the throwing ability of the trivalent chromium plating produced by this method is not very good, and the friction and wear performance also needs to be further improved.

Therefore, the trivalent chromium coating still has certain limitations in the use process. For some parts (such as bearings, pipes, axes, etc.) under heavy load and high wear-resistant environments, the trivalent chromium coating will be used for a period of time. There will be serious wear and even wear. Under such working conditions, the microhardness and wear resistance of the trivalent chromium composite coating need to be further improved.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: the technical problem of poor friction and wear resistance of the existing trivalent chromium coating.

In order to solve the above-mentioned problems, the present invention provides a kind of preparation method of wear-resistant silicon carbide doped composite coating, it is characterized in that, comprises the following steps:

Step 1): put the brass substrate into acetone and ultrasonically clean;

Step 2): adopt chemical method to carry out degreasing to the substrate, then the substrate is immersed in hydrochloric acid solution to carry out pickling activation, removes the oil stain on the surface of the substrate;

Step 3): Electroplating a layer of Cr-SiC-PTFE on the brass substrate.

Preferably, ultrasonic cleaning adopts ultrasonic cleaning instrument in described step 1), and its technological parameters are: power 90w, time 30min.

Preferably, the solution used in the chemical method in the step 2) contains NaOH, Na ₂ CO ₃ and Na ₃ PO ₄ .

More preferably, the concentration of NaOH in the solution is 20 g/L, the concentration of Na ₂ CO ₃ is 30 g/L, and the concentration of Na ₃ PO ₄ is 30 g/L.

More preferably, the chemical method in the step 2) is specifically: heating the solution to 70-80°C, and then placing the substrate in the solution for 10-15min.

Preferably, in the step 2), the volume concentration of the hydrochloric acid solution is 40-60%, the solution temperature is normal temperature, and the soaking time is 4 minutes, so that the oxide layer on the surface of the brass substrate is removed, and a completely exposed brass substrate is obtained, The surface activity of the substrate is greatly enhanced, which is beneficial to the subsequent deposition of the Cr-SiC-PTFE composite coating.

Preferably, the electroplating in the step 3) adopts a trivalent chromium plating solution, the SiC doping amount is 1.25g/L, the concentration of PTFE is 12.5mL/L, the current density is 35A/dm ² , and the pH value is 2.0 , the temperature is 45°C, and the deposition time is 20 minutes.

In the present invention, a layer of Cr-SiC-PTFE is plated on the brass substrate. The preparation of the electroplating coating firstly polishes the surface of the substrate. After ultrasonic cleaning, appropriate chemical degreasing and pickling are performed on the brass substrate. The activated pretreatment process controls the concentration of SiC in the trivalent chromium plating solution during electroplating, and finally obtains a Cr-SiC-PTFE coating as a wear-resistant layer, and the friction coefficient of the obtained Cr-SiC-PTFE composite coating is 0.34 , The hardness reaches the maximum value of 16.5GPa. In particular, the Cr-SiC-PTFE wear-resistant coating obtained when the SiC doping amount in the trivalent chromium plating solution is 1.25 g/L has a more compact and uniform microstructure.

The invention adopts the anti-wear and slip treatment technology of the surface of the base material for preparing the Cr-SiC-PTFE coating by electroplating. By optimizing the preparation process parameters, the Cr-SiC-PTFE anti-wear coating with excellent friction and wear performance and uniform surface is prepared Floor. Compared with the traditional process, the complexity of the process is reduced, the production cost is reduced, and the friction and wear performance of the coating is improved. It has the advantages of fast deposition speed, low cost and good bonding strength.

Description of drawings

Fig. 1 is embodiment 1-7 in the electroplating process, the concentration of SiC in trivalent chromium plating solution is 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g/L respectively. The XRD patterns of the corresponding Cr-SiC-PTFE composite coatings obtained at L and 2.5 g/L;

Fig. 2a is the SEM image of the surface morphology of the electroplated Cr-SiC-PTFE wear-resistant coating obtained when the concentration of SiC in the trivalent chromium electroplating solution is 0 g/L during the electroplating process;

Figure 2b is a SEM image of the surface morphology of the electroplated Cr-SiC-PTFE wear-resistant coating obtained when the concentration of SiC in the trivalent chromium plating solution during the electroplating process is 0.5 g/L;

Fig. 2c is the SEM image of the surface morphology of the electroplated Cr-SiC-PTFE wear-resistant coating obtained when the concentration of SiC in the trivalent chromium plating solution in the electroplating process is 0.75g/L;

Fig. 2d is the SEM image of the surface morphology of the electroplated Cr-SiC-PTFE wear-resistant coating obtained when the concentration of SiC in the trivalent chromium electroplating solution is 1.0 g/L during the electroplating process;

Fig. 2e is when the concentration of SiC in the trivalent chromium electroplating solution in the electroplating process is 1.25g/L, the obtained electroplated Cr-SiC-PTFE wear-resistant coating surface morphology SEM image;

Fig. 2f is when the concentration of SiC in the trivalent chromium plating solution in the electroplating process is 1.75g/L, the obtained electroplated Cr-SiC-PTFE wear-resistant coating surface morphology SEM image;

Fig. 2g is the SEM image of the surface morphology of the electroplated Cr-SiC-PTFE wear-resistant coating obtained when the concentration of SiC in the trivalent chromium electroplating solution in the electroplating process is 2.5g/L;

Fig. 3 is that the concentration of SiC in the trivalent chromium electroplating solution in the electroplating process of embodiment 1-7 is respectively 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g/L , the microhardness and elastic modulus of the corresponding Cr-SiC-PTFE composite coating obtained at 2.5g/L;

Figure 4 shows that the concentrations of SiC in the trivalent chromium plating solution in the electroplating process of Examples 1-7 are 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g/L, respectively , the friction coefficient curve of the corresponding Cr-SiC-PTFE composite coating obtained at 2.5g/L;

Figure 5 shows that the concentrations of SiC in the trivalent chromium plating solution in the electroplating process of Examples 1-7 are 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g/L, respectively , and the wear resistance curve of the corresponding Cr-SiC-PTFE composite coating obtained at 2.5g/L.

Figure 6 shows that the concentrations of SiC in the trivalent chromium plating solution in the electroplating process of Examples 1-7 are 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g/L, respectively , H ³ /E ² (H is hardness, E is elastic modulus) curve of the corresponding Cr-SiC-PTFE composite coating obtained at 2.5 g/L.

Detailed ways

In order to make the present invention more obvious and comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.

Preparation, characterization and measurement instruments used in the present invention:

The Cr-SiC-PTFE layer obtained in each embodiment of the present invention adopts the D8 ADVANCE X-ray diffraction (XRD) instrument of Bruker Company to analyze the crystal phase structure of the film;

The composition, microscopic morphology and thickness of the Cr-SiC-PTFE layer were analyzed by a QuantaFEG450 field emission environment scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS) from FEI Company in the United States;

The hardness and elastic modulus of the composite coating were measured by the NANO Indenter G200 nanoindenter produced by Agilent in the United States;

The friction and wear coefficient of the composite coating was measured with the HSR-2M reciprocating friction and wear meter of Lanzhou Zhongke Huakai Technology Co., Ltd.;

Use the high-frequency rectifier of Shenzhen Fushuntai Technology Co., Ltd. to provide electroplating power (50A, 24V);

The initial and final mass values of each sample were weighed with an XP6 analytical balance (METTLER TOLEDO, Switzerland), and the wear resistance of the composite coating was evaluated by a weight loss method.

Example 1

A preparation method of a wear-resistant silicon carbide doped composite coating, the preparation process comprising the following steps:

(1) matrix is put into the beaker containing 100mL acetone, adopts ultrasonic cleaning 10min, and power is set to 90W;

(2) then adopt the chemical method to degreasing the substrate, the degreasing temperature is 70-80 ℃, the time is 10-15min, and then use the hydrochloric acid with a volume fraction of 40-60% to pickle and activate the substrate for 4min;

(3) A layer of Cr-SiC-PTFE is plated on the brass substrate by electroplating; the concentration of PTFE in the trivalent chromium plating solution is 12.5ml/L, the current density is 35A/dm ² , the pH value is about 2.0, and the temperature was 45°C and the deposition time was 20 minutes.

The base material is an H70 brass sample with a length of 40mm, a width of 40mm and a thickness of 0.3mm.

In the above-mentioned electroplating process, the temperature of the trivalent chromium electroplating solution was controlled to be 45°C, the pH value was 2.0, and the current density was 35A/dm ² , and a magnetic stirrer was used for slow stirring, and the Cr-SiC-PTFE was deposited for 20 minutes to obtain wear-resistant Cr-SiC-PTFE. coating.

Example 2

A preparation method of a wear-resistant silicon carbide doped composite coating, except that in step (3) of the preparation process, the amount of SiC doping in the trivalent chromium plating solution in the electroplating process is 0.5g/L, and the concentration of PTFE is 12.5ml/L, the bath temperature is 45°C, the pH value is 2.0, and the current density is 35A/dm ² .

Others are the same as in Example 1.

Example 3

A preparation method of a wear-resistant silicon carbide doped composite coating, except that in step (3) of the preparation process, the amount of SiC doping in the trivalent chromium electroplating solution in the electroplating process is 0.75g/L, and the concentration of PTFE is 12.5ml/L, the bath temperature is 45°C, the pH value is 2.0, and the current density is 35A/dm ² .

Others are the same as in Example 1.

Example 4

A preparation method of a wear-resistant silicon carbide doped composite coating, except that in step (3) of the preparation process, the amount of SiC doping in the trivalent chromium electroplating solution in the electroplating process is 1.0g/L, and the concentration of PTFE is 12.5ml/L, the bath temperature is 45°C, the pH value is 2.0, and the current density is 35A/dm ² .

Others are the same as in Example 1.

Example 5

A preparation method of a wear-resistant silicon carbide doped composite coating, except that in step (3) of the preparation process, the amount of SiC doping in the trivalent chromium plating solution in the electroplating process is 1.25 g/L, and the concentration of PTFE is 1.25 g/L. 12.5ml/L, the bath temperature is 45°C, the pH value is 2.0, and the current density is 35A/dm ² .

Others are the same as in Example 1.

Example 6

A preparation method of a wear-resistant silicon carbide doped composite coating, except that in step (3) of the preparation process, the amount of SiC doping in the trivalent chromium electroplating solution in the electroplating process is 1.75g/L, and the concentration of PTFE is 12.5ml/L, the bath temperature is 45°C, the pH value is 2.0, and the current density is 35A/dm ² .

Others are the same as in Example 1.

Example 7

A preparation method of a wear-resistant silicon carbide doped composite coating, except that in step (3) of the preparation process, the amount of SiC doping in the trivalent chromium electroplating solution in the electroplating process is 2.5g/L, and the concentration of PTFE is 12.5ml/L, the bath temperature is 45°C, the pH value is 2.0, and the current density is 35A/dm ² .

Others are the same as in Example 1.

To sum up, the present invention obtains the Cr-SiC-PTFE wear-resistant coating by electroplating technology, and controls the concentration of SiC in the electroplating solution during the electroplating process, and finally obtains a Cr-SiC obtained by electroplating technology. -PTFE wear-resistant coating, the obtained Cr-SiC-PTFE composite coating has compact structure, uniform size and excellent wear resistance.

Further, the preparation method of a wear-resistant silicon carbide doped composite coating of the present invention is easy to industrialize production and reduces production cost.

For Examples 1-7, namely the electroplating process, the concentrations of SiC in the trivalent chromium electroplating solution were 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g, respectively. The XRD patterns of the corresponding Cr-SiC-PTFE composite coatings obtained at /L and 2.5g/L were measured. The results are shown in Figure 1. It can be seen from Figure 1 that the Cr-SiC under different SiC concentrations -The shape of the spectrum of the PTFE composite coating is similar. Under the condition of keeping the current density, plating time, PTFE concentration, pH value and temperature unchanged during the electroplating process, the XRD patterns of the Cr-SiC-PTFE composite coatings with different SiC concentrations were prepared The diffraction peaks of Cr appear in the spectral lines at 2θ=44.3°. According to the XRD pattern, with the continuous increase of SiC concentration, the diffraction peak intensity of trivalent chromium increases first and then decreases, that is to say, the crystal intensity of the Cr-SiC-PTFE composite coating first increases and then decreases. When the SiC concentration is 1.25 g/L, the diffraction peak of trivalent chromium is the strongest, and the diffraction peaks of trivalent chromium at other SiC concentrations are relatively weak, indicating that the Cr phase formed in the coating has better crystallinity; but in the XRD pattern The diffraction peaks of PTFE and SiC were not observed in Cr-SiC-PTFE composite coating because the content of PTFE and SiC nanoparticles in the Cr-SiC-PTFE composite coating was small.

For Examples 1-7, namely the electroplating process, the concentrations of SiC in the trivalent chromium electroplating solution were 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g, respectively. The surface morphology SEM images of the corresponding Cr-SiC-PTFE composite coatings obtained at /L and 2.5g/L were measured. The surface morphology SEM images are shown in Figures 2a, 2b, 2c, 2d, 2e, 2f, 2g, respectively As shown in the figure, Figure 2a is the SEM image when the SiC concentration is 0 g/L. It can be seen that there are small black dots evenly distributed on the surface of the coating, and the small black dots are the PTFE particles distributed in the Cr-SiC-PTFE composite coating. Figures 2b, 2c, 2d, 2e, 2f, and 2g are the SEM images when SiC is added. At this time, small balls appear, and the small balls are the SiC particles in the distributed Cr-SiC-PTFE composite coating, PTFE particles and The SiC particles are encapsulated within a trivalent chromium matrix coating. When the concentration increased from 0g/L to 1.25g/L, the PTFE particles in the Cr-SiC-PTFE composite coating gradually decreased, while the SiC particles gradually increased, and the SiC particles in the Cr-SiC-PTFE composite coating became more uniformly dispersed. When the concentration of SiC increases, the probability of SiC particles embedded in the coating increases during the electroplating process, so that the amount of SiC particles entering the coating surface also increases. When the rate at which SiC particles enter the coating surface is equal to the rate at which SiC particles are embedded in the coating, the coating The SiC particles in the maximum value. When the concentration increased from 1.25g/L to 2.5g/L, the amount of SiC particles entering the coating decreased, because at this concentration, with the increase of SiC concentration, there were too many SiC particles and the collision between particles intensified, SiC and PTFE particles agglomerate and settle in the trivalent chromium plating solution, resulting in increased instability of the plating solution. The PTFE and SiC particles are not uniformly suspended in the trivalent chromium plating solution, and the adsorption amount of the particles on the coating surface decreases. , the compound amount no longer increases, or even decreases, so that the quality of the coating surface gradually declines, and the appearance becomes worse.

For Examples 1-7, namely the electroplating process, the concentrations of SiC in the trivalent chromium electroplating solution were 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g, respectively. The microhardness and elastic modulus of the corresponding Cr-SiC-PTFE composite coatings obtained at /L and 2.5g/L were measured, and the curves were fitted as shown in Figure 3. From the curve in Figure 3, it can be seen that It can be seen that with the increase of SiC particle concentration, the hardness of the coating first increases and then decreases. The microhardness of the Cr-SiC-PTFE composite coating is affected by the content of SiC and PTFE particles in the coating. Because the hardness of SiC particles is high (31.3GPa), when the SiC concentration in the trivalent chromium plating solution increases from 0 g/L to 1.25 g/L, the SiC content in the Cr-SiC-PTFE composite coating increases and the PTFE particle content decreases. , SiC and PTFE particles are dispersed in the coating, resulting in the effect of dispersion strengthening, which increases the hardness of the Cr-SiC-PTFE composite coating. When the SiC concentration is 1.25g/L, the SiC particles in the coating reach the maximum value. , Cr-SiC-PTFE composite coating has the highest hardness. When the concentration increased from 1.25g/L to 2.5g/L, with the increase of SiC concentration, the amount of SiC particles in the composite coating decreased, and the content of PTFE particles continued to decrease. The decrease of SiC content in the coating had a greater impact on the hardness of the coating. , and at this time, SiC and PTFE particles agglomerated and settled in the trivalent chromium plating solution, and the effective concentration of SiC and PTFE particles in the trivalent chromium plating solution decreased significantly, so the hardness of the composite coating continued with the concentration of SiC in the plating solution. increase and decrease. It can be seen from Figure 3 that the change trend of the elastic modulus of the Cr-SiC-PTFE composite coating is basically consistent with the change trend of the hardness.

For Examples 1-7, namely the electroplating process, the concentrations of SiC in the trivalent chromium electroplating solution were 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g, respectively. The friction coefficients of the corresponding Cr-SiC-PTFE composite coatings obtained at /L and 2.5g/L were measured and fitted to the friction coefficient curve as shown in Figure 4. With the increase of SiC concentration, the friction coefficient of the coating Has been increased, the lubricating performance decreased. The friction coefficient of the Cr-SiC-PTFE composite coating is mainly affected by the content of PTFE in the coating, because PTFE particles have a very low friction coefficient. When the coating rubs the surface of the object, the PTFE particles are easily extruded into the surface layer to form Uniform lubricating film. When the concentration increases from 0g/L to 1.25g/L, the composite amount of PTFE particles in the Cr-SiC-PTFE composite coating gradually decreases, and the friction coefficient of the coating increases slowly. With the increase of SiC particles, the more SiC particles are sent to the surface of the plated parts by stirring, the probability of SiC particles being embedded in the coating increases, which affects the embedding of PTFE particles and reduces the proportion of PTFE particles adsorbed on the surface of the plated parts. The PTFE particles in the Cr-SiC-PTFE composite coating decreased gradually. When the concentration increased from 1.25g/L to 2.5g/L, with the further increase of the SiC concentration in the trivalent chromium composite plating solution, at this time, the content of SiC in the plating solution was too high, and the stability of the composite plating solution decreased significantly. It is difficult for SiC and PTFE nanoparticles to maintain a uniform and stable suspension state, thereby reducing the effective concentration of PTFE in the plating solution, the content of PTFE in the Cr-SiC-PTFE composite coating is significantly reduced, and the friction coefficient of the coating is increased. , the lubrication performance is further reduced.

For Examples 1-7, namely the electroplating process, the concentrations of SiC in the trivalent chromium electroplating solution were 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g, respectively. The wear resistance of the corresponding Cr-SiC-PTFE composite coatings obtained at /L and 2.5g/L was measured, and the wear characteristic curve was fitted as shown in Figure 5. , the wear amount of the Cr-SiC-PTFE composite coating first decreased and then increased. The wear resistance of the coating is closely related to the hardness and friction coefficient of the coating. The higher the hardness of the coating, the stronger the ability of the coating surface to resist plastic deformation. low level, thus has better anti-wear properties. When the SiC concentration in the trivalent chromium plating solution is 0.0-1.25g/L, it can be seen from Figure 3 and Figure 4 that the hardness of the coating increases with the increase of the SiC concentration, while the friction coefficient does not increase much and is at a lower level , so the wear amount of the Cr-SiC-PTFE composite coating decreases with the increase of SiC concentration. When the SiC concentration is 1.25g/L, the wear amount of the composite coating is the lowest, showing better wear resistance. As the SiC concentration continues to increase, the hardness of the coating decreases, and the friction coefficient increases all the time, so the wear amount of the composite coating increases and the wear resistance decreases.

的比 值来评价材料的耐磨性，即H³/E²的比值越大，则表面镀层材料的耐磨性越好。 如图6所示，随着SiC浓度的增加，H³/E²的比值先升高后降低，这表明 Cr-SiC-PTFE复合涂层的耐磨性先增大后降低，在SiC浓度为1.25g/L时，复合 镀层的耐磨性最佳，这与图5通过磨损量测的涂层耐磨性结果一致。For Examples 1-7, namely the electroplating process, the concentrations of SiC in the trivalent chromium electroplating solution were 0g/L, 0.5g/L, 0.75g/L, 1.0g/L, 1.25g/L, 1.75g, respectively. The wear resistance H3/E2 (H is the hardness, E is the elastic modulus) of the corresponding Cr-SiC-PTFE composite coating obtained at the time of /L, 2.5g/L was measured, and fitted to the H3/E2 characteristic curve As shown in Figure 6, for coating materials, most academic researchers commonly use

The ratio of H 3 /E 2 to evaluate the wear resistance of the material, that is, the greater the ratio of H ³ /E ² , the better the wear resistance of the surface coating material. As shown in Fig. 6, with the increase of SiC concentration, the ratio of H ³ /E ² increases first and then decreases, which indicates that the wear resistance of the Cr-SiC-PTFE composite coating first increases and then decreases. At 1.25g/L, the wear resistance of the composite coating is the best, which is consistent with the wear resistance results of the coating measured by wear in Figure 5.

From the above examples, it is realized that by controlling the concentration of SiC in the trivalent chromium plating solution, Cr-SiC-PTFE composite coatings with different SiC contents are finally obtained. The influence of microstructure and mechanical properties shows that when the concentration of PTFE is 12.5ml/L, the current density is 35A/dm ² , the pH value is about 2.0, the temperature is 45°C, and the deposition time is 20 minutes, Cr-SiC- The optimal SiC doping amount of PTFE composite coating is 1.25g/L. The Cr-SiC-PTFE composite coating prepared at this doping amount has a dense structure, uniform grain size, tight bonding between the coating and the substrate, and has the best surface wear resistance.

Claims (7)

1. A preparation method of a wear-resistant silicon carbide doped composite coating is characterized by comprising the following steps:

step 1): placing the brass base material into acetone, and ultrasonically cleaning;

step 2): degreasing the matrix by a chemical method, and then soaking the matrix in a hydrochloric acid solution for pickling and activating to remove oil stains on the surface of the matrix;

step 3): electroplating a layer of Cr-SiC-PTFE on the brass substrate.

2. The method for preparing the wear-resistant silicon carbide doped composite coating according to claim 1, wherein the ultrasonic cleaning in the step 1) adopts an ultrasonic cleaning instrument, and the process parameters are as follows: power 90w, time 30 min.

3. The method for preparing the wear-resistant silicon carbide doped composite coating according to claim 1, wherein the chemical method in the step 2) adopts a solution containing NaOH and Na₂CO₃And Na₃PO₄。

4. The method of claim 3, wherein the NaOH concentration in the solution is 20g/L and Na₂CO₃Has a concentration of 30g/L, Na₃PO₄The concentration of (2) was 30 g/L.

5. The method for preparing the wear-resistant silicon carbide doped composite coating according to claim 3, wherein the chemical method in the step 2) is specifically as follows: the solution is heated to 70-80 deg.C, and then the substrate is placed in the solution for 10-15 min.

6. The method for preparing the wear-resistant silicon carbide doped composite coating according to claim 1, wherein the volume concentration of the hydrochloric acid solution in the step 2) is 40-60%, the solution temperature is normal temperature, and the soaking time is 4 min.

7. The method for preparing the wear-resistant silicon carbide doped composite coating according to claim 1, wherein the electroplating in the step 3) adopts trivalent chromium electroplating solution, the SiC doping amount is 1.25g/L, the concentration of PTFE is 12.5mL/L, and the current density is 35A/dm²The pH was 2.0, the temperature was 45 ℃ and the deposition time was 20 minutes.

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