阅读说明：本技术 一种Ni-W-WC复合镀层的原位合成方法 (In-situ synthesis method of Ni-W-WC composite coating ) 是由 王慧华 徐英君 盛施展 王德永 屈天鹏 田俊 侯栋 李向龙 胡绍岩 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种Ni-W-WC复合镀层的原位合成方法。包括以下步骤：将待镀碳钢基材浸入电镀液中进行电镀,以在所述碳钢基材表面获得Ni-W-C合金镀层,并将该合金镀层进行高温热处理得到所述的Ni-W-WC复合镀层。所述电镀液包括以下组分：镍盐、钨酸盐、柠檬酸、柠檬酸盐、增碳剂、湿润剂。本发明操作简单、电流效率高,电镀工艺简单、清洁不污染,符合环保要求。(The invention discloses an in-situ synthesis method of a Ni-W-WC composite coating. The method comprises the following steps: and immersing the carbon steel base material to be plated in electroplating solution for electroplating to obtain a Ni-W-C alloy plating layer on the surface of the carbon steel base material, and performing high-temperature heat treatment on the alloy plating layer to obtain the Ni-W-WC composite plating layer. The electroplating solution comprises the following components: nickel salt, tungstate, citric acid, citrate, carburant and wetting agent. The invention has simple operation, high current efficiency, simple electroplating process, cleanness without pollution and conforms to the requirement of environmental protection.)

1. An in-situ synthesis method of a Ni-W-WC composite coating is characterized by comprising the following steps: immersing a base material to be plated into electroplating solution for electroplating to obtain a Ni-W-C alloy plating layer on the surface of the base material, and carrying out heat treatment on the alloy plating layer to obtain the Ni-W-WC composite plating layer; the electroplating solution comprises the following components: nickel salt, tungstate, citric acid, citrate, carburant and wetting agent.

2. The in-situ synthesis method according to claim 1, wherein the nickel salt is one or more of nickel sulfate, nickel sulfonate and nickel chloride.

3. The in situ synthesis method of claim 1, wherein the tungstate is sodium tungstate.

4. The in-situ synthesis method according to claim 1, wherein the carburant is one or more of 2- (4-pyridyl) ethanesulfonic acid, 2-pyridinesulfonic acid, 3-pyridinesulfonic acid and propanesulfonic acid pyridinium salt.

5. The in situ synthesis method according to claim 1, wherein the concentrations of the components in the electroplating solution are as follows: 20-70g/L of nickel salt, 30-85g/L of tungstate, 7-35g/L of citric acid, 10-70g/L of citrate, 1-14g/L of carburant and 0.5-9.5mL/L of wetting agent.

6. The in situ synthesis method according to claim 1, wherein the electroplating solution is prepared by: mixing nickel salt, tungstate, citric acid, citrate and nickel salt, adding the mixture into water, stirring until the mixture is dissolved to obtain a mixed solution, adding a carburant and a wetting agent, uniformly mixing, and adjusting the pH value of the obtained solution to 7.5-7.8 to obtain the electroplating solution.

7. The in-situ synthesis method according to claim 1, wherein the cathodic current density during the electroplating process is 2-5A/dm²。

8. The in-situ synthesis method of claim 1, wherein the Ni-W-C alloy coating has a C content of 7-12 wt.% and a W content of 35-45 wt.%.

9. The in-situ synthesis method as claimed in claim 1, wherein the temperature of the heat treatment of the Ni-W-C alloy plating layer is 700-1000 ℃.

10. The in-situ synthesis method according to claim 1, wherein the Ni-W-WC composite coating has a thickness of 10-20 μm.

Technical Field

The invention belongs to the technical field of metal surface engineering, and particularly relates to an in-situ synthesis method of a Ni-W-WC composite coating.

Background

With the rapid development of surface engineering technology, coatings with special functionality are receiving increasing attention. The hard chromium plating layer has the characteristics of high hardness and high corrosion resistance, is widely applied to the field of surface engineering, but has the defects of great harm of plating solution, high electroplating energy consumption, low current efficiency and the like, so that the technology is gradually eliminated and replaced by an environment-friendly and economic chromium-substituted plating layer. The Ni-W alloy coating combines the dual advantages of nickel and tungsten metal, has obviously better corrosion resistance and wear resistance than other nickel-based metal alloys, and can be used as a coating material for the surfaces of workpieces such as bearings, pistons, cylinders, petroleum pipelines and the like. In addition, the Ni-W alloy plating layer has good corrosion resistance, for example, neutral salt fog can reach 120h without color change, the hardness can reach 600Hv, and the hardness can reach 1000Hv after heat treatment at 400 ℃ for 2h, which exceeds that of a hard chromium plating layer, so the Ni-W alloy plating layer becomes an important chromium-substituted plating layer. For Ni-W alloy, when the tungsten content in the alloy reaches more than 20%, the brittleness of the plating layer is obviously increased, the interface bonding force is rapidly deteriorated, although the brittleness is reduced after heat treatment, the interface bonding force cannot be fundamentally improved, and the plating layer can be peeled off in serious cases, so that the internal stress of the high-tungsten Ni-W alloy plating layer is reduced, and the improvement of the interface bonding force becomes a hot spot concerned by the current chromium-replacing process.

In order to further increase the hardness and wear resistance of the Ni-W alloy coating, a composite plating technique is generally used, in which a certain amount of micron-sized or nano-sized hard particles are added to the plating solution during the electroplating process, and the hard particles are dispersed and distributed in the Ni-W alloy coating to form the composite coating. At present, TiO is selected as the hard particle of the Ni-W composite coating₂、ZrO₂Diamond, silicon carbide, WC, Al₂O₃And the like. Among them, WC is a relatively common plating reinforcing particle because of its characteristics of high hardness, excellent wear resistance, and high chemical stability. Research shows that WC can be well wetted by Co, Ni, Fe and other metals, so that WC is adoptedThe Ni-W composite plating prepared by the method as a particle reinforcing agent can improve the hardness and the high-temperature stability of the plating. Chinese patent CN101122043 describes a method for preparing a nano tungsten carbide-nickel composite coating for hydraulic machinery, in which nano tungsten carbide powder is added into electroplating solution, and the formed coating can be used as a corrosion-resistant and wear-resistant member material for hydraulic machinery, the method has the characteristics of high powder utilization rate and low production cost, but the aggregation phenomenon of WC particles is easily generated in the electroplating solution, and impurities are easily wrapped, so that the defects of large porosity and rough coating are often existed when WC particles are directly used as reinforcing particles to be compounded into a coating texture crystal phase. The documents of Effects of WC addition on structure and hardness of electrically deposited Ni-W (doi.org/10.1016/j.surfcoat.2009.05.027) describe the preparation of Ni-W/WC composite coatings by adding WC particles, and research shows that the process parameters including current density, particle content and particle size all affect the surface morphology of the coating, thereby affecting the apparent hardness of the co-deposit. As can be seen from the above, the method of obtaining a composite plating layer by adding particles to a plating solution has a narrow process window and a low amount of WC doped in the plating layer. Therefore, the development of a novel Ni-W-WC composite plating process has important significance.

Disclosure of Invention

In order to solve the technical problems, the invention provides an in-situ synthesis method of a Ni-W-WC composite coating. The invention has simple operation, high current efficiency, simple electroplating process, cleanness without pollution and conforms to the requirement of environmental protection.

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following steps: immersing a base material to be plated into electroplating solution for electroplating to obtain a Ni-W-C alloy plating layer on the surface of the carbon steel base material, and carrying out high-temperature heat treatment on the alloy plating layer to obtain the Ni-W-WC composite plating layer; the electroplating solution comprises the following components: nickel salt, tungstate, citric acid, citrate, carburant and wetting agent. The base material is a carbon steel base material.

In one embodiment of the present invention, the nickel salt is one or more of nickel sulfate, nickel sulfonate and nickel chloride.

In one embodiment of the invention, the tungstate is sodium tungstate.

In one embodiment of the invention, the carburant is one or more of 2- (4-pyridyl) ethanesulfonic acid, 2-pyridinesulfonic acid, 3-pyridinesulfonic acid and pyridine propanesulfonate.

In one embodiment of the invention, the wetting agent is one or more of XP-70, XP-80, XP-90, X-100 and X-114.

In one embodiment of the present invention, the component concentrations in the plating solution are: 20-70g/L of nickel salt, 30-85g/L of tungstate, 7-35g/L of citric acid, 10-70g/L of citrate, 1-14g/L of carburant and 0.5-9.5mL/L of wetting agent.

In one embodiment of the present invention, the plating solution is prepared by the following method: mixing nickel salt, tungstate, citric acid, citrate and nickel salt, adding the mixture into water, stirring until the mixture is dissolved to obtain a mixed solution, adding a carburant and a wetting agent, uniformly mixing, and adjusting the pH value of the obtained solution to 7.5-7.8 to obtain the electroplating solution.

In one embodiment of the invention, in the electroplating process, the anode material is an iridium-tantalum alloy anode material, and the cathode is a carbon steel substrate.

In one embodiment of the invention, the cathodic current density is 2-5A/dm during said electroplating²。

In one embodiment of the invention the C content in the electroplated Ni-W-C alloy is 7-12 wt.% and the W content is 35-45 wt.%.

In one embodiment of the invention, the heat treatment temperature of the Ni-W-WC composite coating is 700-1000 ℃, and the heat preservation time is 2 h.

In one embodiment of the invention, the Ni-W-WC composite coating has a thickness of 10-20 μm.

Compared with the prior art, the technical scheme of the invention has the following advantages:

according to the electroplating solution, citrate and a carburant are used as carbon sources, decomposition intermediate products of the citrate and the carburant are promoted to be adsorbed on the surface of a plating layer as far as possible by adjusting process parameters, and the decomposition intermediate products are included in the plating layer in the electrodeposition process, so that a Ni-W-C alloy plating layer is obtained.

The high-tungsten Ni-W-C alloy plating layer is prepared by adding a carburant into electroplating liquid for electroplating, wherein the W content of the plating layer reaches 35-45 wt%, and the C content is 7-12 wt%. The C inclusion in the coating can not only obviously reduce the internal stress of the Ni-W coating, but also mostly gather near the grain boundary because of low solubility in the Ni-W alloy coating, and the tungsten atoms have large atomic radius and have the tendency of strong segregation to the grain boundary or phase boundary. At a certain temperature, after the segregated tungsten atoms reach a certain concentration, the segregated tungsten atoms react with carbon atoms at a grain boundary to form nano-scale WC particles in situ, and the nano-scale WC particles are dispersed in the coating, so that the wear resistance, corrosion resistance and high-temperature thermal stability of the coating are effectively enhanced.

The Ni-W-WC composite coating prepared by the invention has a nanocrystalline structure or an amorphous structure, has the advantages of smooth surface, fine crystallization, uniform components, fine crystal grains, less defects, high hardness (1500-2000Hv), high corrosion resistance, self lubrication, strong interface bonding force and the like.

The WC particles obtained by the method belong to in-situ synthesis, can avoid the adverse factors of easy agglomeration of additional WC particles, poor interface wettability and limitation of addition amount and size in the traditional composite plating process, and meanwhile, the Ni-W-C alloy plating layer doped with C has macroscopic stress obviously smaller than that of the traditional Ni-W alloy plating layer, and particularly for the Ni-W alloy plating layer with high tungsten content, the factors promote the Ni-W-WC composite plating layer synthesized in situ to have more excellent mechanical properties.

Drawings

In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which

FIG. 1 shows the morphology and elemental composition of the coatings obtained in example 2 and comparative example 2 of the present invention, wherein (a) is the coating obtained without adding a carburant to the plating bath, and (b) is the coating obtained by adding a carburant to the plating bath.

FIG. 2 is an XPS survey spectrum of a plated layer obtained in example 2 of the present invention.

FIG. 3 is a high resolution analysis of C1s in the deposit obtained in example 2 of the present invention.

FIG. 4 is an SEM image of the morphology of the coating after heat treatment obtained in example 2 of the present invention.

FIG. 5 is an XRD pattern of the heat-treated plating layer obtained in example 2 of the present invention.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

Example 1

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.5 by using ammonia water. The plating solution composition is shown in table 1:

TABLE 1 electroplating bath composition in example 1

(2) Pretreating a carbon steel substrate: 180# -240# carborundum polished carbon steel substrate surface (10 multiplied by 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 1 into an electroplating bath, using a corrugated iron plate as a cathode, using stainless steel as an anode material, and adopting a constant-voltage direct-current power supply to perform low-current electricityDecomposing to make the complexing agent and additive in the newly-prepared plating solution quickly enter the optimum state, controlling the temperature to 65 ℃ and the cathode current density to be 1A/dm during electrolysis²And (4) electrolyzing for 10 hours. (pretreating the new plating solution, electrolyzing with small current to make the complexing agent and additive in the new plating solution enter the optimum state quickly)

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 65 ℃, and the current density of the cathode is 2A/dm²And the electroplating time is 60min, and a coating with the thickness of 10 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: c is 50: 40: 10.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (5) heating the coating obtained in the step (4) to 700 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and preserving heat for 3 hours. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Example 2

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, and finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume

Volume is required and the pH of the solution is adjusted to 7.6 with ammonia. The plating solution composition is shown in table 2:

TABLE 2 electroplating bath composition in example 2

(2) Matrix pretreatment: 180# -240# diamondSand polishing carbon steel substrate surface (10X 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 2 into an electroplating bath, using a corrugated board iron plate as a cathode, using stainless steel as an anode material, and performing low-current electrolysis by using a constant-voltage direct-current power supply to enable complexing agents and additives in newly-prepared electroplating solution to rapidly enter an optimal state, wherein the temperature is controlled to be 67 ℃ and the current density of the cathode is 1A/dm during electrolysis²And (4) electrolyzing for 12 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 67 ℃, and the current density of the cathode is 3A/dm²And the electroplating time is 50min, and a coating with the thickness of 15 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: 46.3: 41.7: 12.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (5) heating the coating obtained in the step (4) to 800 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and keeping the temperature for 2 hours. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Example 3

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.7 by using ammonia water. The plating solution composition is shown in table 3:

TABLE 3 electroplating bath composition in example 3

(2) Carbon steel base material pretreatment: 180# -240# carborundum polished carbon steel substrate surface (10 multiplied by 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 3 into an electroplating bath, using a corrugated board iron plate as a cathode, using stainless steel as an anode material, and performing low-current electrolysis by using a constant-voltage direct-current power supply to enable complexing agents and additives in newly-prepared electroplating solution to rapidly enter an optimal state, wherein the temperature is controlled to be 68 ℃ during electrolysis, and the current density of the cathode is 1A/dm²And (4) electrolyzing for 10 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 68 ℃, and the current density of the cathode is 4A/dm²And the electroplating time is 45min, and a coating with the thickness of 17 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: c-48.4: 42.4: 9.2.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (4) heating the coating obtained in the step (4) to 900 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and preserving heat for 2 h. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Example 4

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.8 by using ammonia water. The plating solution composition is shown in table 4:

TABLE 4 electroplating bath composition in example 4

(2) Carbon steel base material pretreatment: 180# -240# carborundum polished carbon steel substrate surface (10 multiplied by 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 4 into an electroplating bath, using a corrugated board iron plate as a cathode, using stainless steel as an anode material, and performing low-current electrolysis by using a constant-voltage direct-current power supply to enable complexing agents and additives in newly-prepared electroplating solution to rapidly enter an optimal state, wherein the temperature is controlled to be 70 ℃ and the current density of the cathode is 1.2A/dm during electrolysis²And (4) electrolyzing for 12 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of carbon steel anode material, the temperature of the electroplating solution is kept at 70 ℃, and the cathode current density is 5A/dm²Electroplating for 40min to obtain a coating with a thickness of 20 μm, wherein the mass ratio of each element in the coating is aboutIs Ni: w: c44.5: 45: 10.5

(5) In-situ synthesis of a Ni-W-WC composite coating: and (4) heating the coating obtained in the step (4) to 900 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and preserving heat for 2 h. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Comparative example 1 (without addition of carburant)

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.6 by using ammonia water. The plating solution composition is shown in table 5:

TABLE 5 composition of plating solution in comparative example 1

(2) Matrix pretreatment: polishing the surface of the carbon steel substrate (10 multiplied by 10 cm) by using 180# -240# carborundum²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 5 into an electroplating bath, using a corrugated board iron plate as a cathode, using stainless steel as an anode material, and performing low-current electrolysis by using a constant-voltage direct-current power supply to enable complexing agents and additives in newly-prepared electroplating solution to rapidly enter an optimal state, wherein the temperature is controlled to be 67 ℃ and the current density of the cathode is 1A/dm during electrolysis²And (4) electrolyzing for 12 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 67 ℃, and the current density of the cathode is 3A/dm²And the electroplating time is 50min, and a coating with the thickness of 15 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: c56.8: 40.5: 2.7.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (5) heating the coating obtained in the step (4) to 800 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and keeping the temperature for 2 hours. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

COMPARATIVE EXAMPLE 2 (Low Current Density electroplating)

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.6 by using ammonia water. The plating solution composition is shown in Table 2.

(2) Matrix pretreatment: 180# -240# carborundum polished carbon steel substrate surface (10 multiplied by 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 2 into an electroplating bath, using a corrugated iron plate as a cathode, using stainless steel as an anode material, and performing low-current electrolysis by using a constant-voltage direct-current power supply to ensure that the newly-prepared electroplating solution isThe complexing agent and the additive in the electrolytic solution quickly enter the optimal state, the temperature is controlled to be 67 ℃, and the cathode current density is 1A/dm²And (4) electrolyzing for 12 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 67 ℃, and the current density of the cathode is 1.5A/dm²And the electroplating time is 60min, and a coating with the thickness of 15 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: c58.6: 35: 6.4.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (5) heating the coating obtained in the step (4) to 800 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and keeping the temperature for 2 hours. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Comparative example 3(600 ℃ C. heat treatment)

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.6 by using ammonia water. The plating solution composition is shown in Table 2.

(2) Matrix pretreatment: 180# -240# carborundum polished carbon steel substrate surface (10 multiplied by 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: an appropriate amount of the plating solution having the composition shown in Table 2 was added to the platingIn the tank, corrugated board iron plate is used as cathode, stainless steel is used as anode material, constant voltage DC power supply is used for small current electrolysis to make complexing agent and additive in newly-prepared plating solution quickly enter optimum state, and during electrolysis, the temperature is controlled at 67 deg.C, and the cathode current density is 1A/dm²And (4) electrolyzing for 12 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 67 ℃, and the current density of the cathode is 3A/dm²And the electroplating time is 50min, and a coating with the thickness of 15 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: 46.3: 41.7: 12.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (5) heating the coating obtained in the step (4) to 600 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and preserving heat for 2 hours. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Comparative example 4(1000 ℃ C. heat treatment)

A preparation method for in-situ synthesis of a Ni-W-WC composite coating comprises the following specific processes:

(1) preparing an electroplating solution: adding 300mL of deionized water into a cleaned No. 1 beaker, heating to 65 ℃, adding a certain mass of nickel sulfate solid, and stirring until the nickel sulfate solid is completely dissolved. Heating 300mL of deionized water to 75 ℃ in a No. 2 beaker, sequentially adding sodium citrate, citric acid, ammonium citrate and sodium tungstate, and stirring until the sodium citrate, the citric acid, the ammonium citrate and the sodium tungstate are completely dissolved. Slowly adding the liquid in the No. 1 beaker into the No. 2 beaker, then adding the carburant and the wetting agent, stirring until the carburant and the wetting agent are completely dissolved, finally adding deionized water to fix the volume of the No. 2 beaker solution to the required volume, and adjusting the pH value of the solution to 7.6 by using ammonia water. The plating solution composition is shown in Table 2.

(2) Matrix pretreatment: 180# -240# carborundum polished carbon steel substrate surface (10 multiplied by 10 cm)²) Washing with deionized water to neutral, chemically removing oil at 65 deg.C with 350mL oil removing reagent (mixed solution of 8g/L sodium hydroxide, 2g/L sodium silicate, 1.5g/L sodium carbonate, and 0.5g/L sodium citrate), washing with 10% H₂SO₄Washing with water to neutrality after acid washing for 10 min;

(3) small current electrolysis: adding a proper amount of electroplating solution with the composition shown in Table 2 into an electroplating bath, using a corrugated board iron plate as a cathode, using stainless steel as an anode material, and performing low-current electrolysis by using a constant-voltage direct-current power supply to enable complexing agents and additives in newly-prepared electroplating solution to rapidly enter an optimal state, wherein the temperature is controlled to be 67 ℃ and the current density of the cathode is 1A/dm during electrolysis²And (4) electrolyzing for 12 hours.

(4) Preparing a Ni-W-C alloy coating by electrodeposition: electroplating the base material obtained in the step (2) in the electroplating solution treated in the step (3), wherein the specific electroplating conditions are as follows: the anode is made of iridium-tantalum alloy, the cathode is made of pretreated carbon steel substrate, the temperature of the electroplating solution is kept at 67 ℃, and the current density of the cathode is 3A/dm²And the electroplating time is 50min, and a coating with the thickness of 15 mu m is obtained, wherein the mass ratio of each element in the coating is about Ni: w: 46.3: 41.7: 12.

(5) in-situ synthesis of a Ni-W-WC composite coating: and (5) heating the coating obtained in the step (4) to 1000 ℃ at a heating rate of 5 ℃/min in an argon protective atmosphere furnace, and preserving heat for 2 hours. Cooling to about 200 ℃ along with the furnace, discharging and air cooling.

Test example

The Ni-W-WC composite coating is synthesized in situ, and the test characterization is as follows:

1 characterization of the coating

The coating obtained in example 2 was characterized by the results shown in FIGS. 1 to 4.

Wherein, fig. 1 is a surface morphology SEM atlas and an element composition of the plating layer, and it can be seen that the addition of the carburant has no significant influence on the surface morphology and the W content of the plating layer, but can significantly change the C content in the plating layer. The W content in the coating to which no carburant was added was 40.5 wt.%, and the C content was 2.7 wt.%; the W content of the coating layer added with the carburant was 41.7 wt.%, and the C content was 12 wt.%.

Fig. 2 shows that the carbon element in the resulting coating exists mainly in the form of C-C, indicating that there is a large amount of organic inclusions in the coating.

FIG. 3 shows the surface morphology of the Ni-W-C coating after heat treatment at 800 ℃, wherein the polygonal particles are in-situ generated tungsten carbide particles which are uniformly dispersed in the coating.

Fig. 4 is an XRD analysis of the plated layer after heat treatment, in which the peak marked by a triangle symbol is a peak of tungsten carbide, and the content of tungsten carbide in the resulting plated layer is 3 to 7 wt.% by analyzing the peak intensity, and the grain size of tungsten carbide is about 30 to 35nm as calculated by scherrer's equation, which is consistent with the WC grain size observed from the SEM atlas, indicating that the Ni-W-WC composite plated layer is prepared in situ.

2, hardness test

The coatings obtained in examples 1 to 4 and comparative examples 1 to 4 were subjected to hardness tests, and the results of the tests are shown in Table 6.

TABLE 6

The elements of the plating layer after the heat treatment at 1000 ℃ are not uniformly distributed, the hardness difference of each area is large, and the condition that the heat treatment temperature is too high is shown.

As can be seen from Table 6, the Ni-W-WC composite coating can be synthesized in situ by adding the carburant and carrying out high-temperature heat treatment (more than 700 ℃), but no WC precipitation is found in the coating which is not added with the carburant or is added with the carburant and is deposited under low current density or has lower heat treatment temperature (less than or equal to 600 ℃), which indicates whether the carburant is added into the electroplating solution or not, and the current density and the heat treatment temperature are both necessary conditions for the preparation process of the in-situ synthesized Ni-W-WC composite coating. By integrating the law of influence of electrodeposition conditions and heat treatment temperature on final performance, and based on the principle of energy consumption reduction and short time consumption, the invention preferably selects a preparation process for in-situ synthesis of the Ni-W-WC composite coating, which comprises the following steps: the formula of the electroplating solution is NiSO₄·6H₂O 40g/L，Na₂WO₄·2H₂O 50g/L，Na₃C₆H₅O₇·2H₂O 45g/L，C₆H₈O₇20 g/L，C₆H₁₇N₃O₇5g/L, 6g/L of 3-pyridine sulfonic acid and X-1146 mL/L; the electrodeposition condition is 3A/cm²The time is 50 min; the heat treatment temperature of the plating layer is 800 ℃, and the treatment time is 2 hours.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the spirit or scope of the invention.