阅读说明：本技术 一种铝合金用镀镍液 (Nickel plating solution for aluminum alloy ) 是由 张政 于 2021-07-27 设计创作，主要内容包括：本发明提供了一种铝合金用电镀液,所述电镀液中包括有主盐、缓冲剂、光亮剂、ZrC分散液,所述分散液中包括有经过预处理的ZrC和硫酸水溶液,所述ZrC依次经过碱洗、酸洗、超声、羟基氧化处理、接枝处理、水解处理；有效提高了ZrC的分散性,在镍镀液中无机颗粒能维持1周不沉降,获得的镀层中的ZrC也呈高度分散状。(The invention provides an electroplating solution for aluminum alloy, which comprises main salt, a buffering agent, a brightener and a ZrC dispersion liquid, wherein the dispersion liquid comprises pretreated ZrC and a sulfuric acid aqueous solution, and the ZrC is subjected to alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment in sequence; the dispersity of ZrC is effectively improved, inorganic particles in the nickel plating solution can not be settled for 1 week, and ZrC in the obtained plating layer is highly dispersed.)

1. The nickel plating solution for the aluminum alloy is characterized by comprising 300g/L of nickel sulfate 250-one, 30-40g/L of nickel chloride, 30-35g/L of boric acid, 1-2 g/L of benzenesulfonic acid main brightener, 0.2-0.4 g/L of butynediol inferior brightener, 0.1-0.2 g/L of sodium ethylene sulfonate auxiliary brightener, 0.01-0.02 g/L of sodium dodecyl sulfate and 5-25g/L of ZrC dispersion liquid, wherein the ZrC dispersion liquid is prepared by the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment on the nano-particles;

wherein the hydroxyl oxidation treatment is to place the ZrC particles after ultrasonic treatment in 30-35wt.% NaOH, 100-^oC, refluxing, and introducing 3-5vol₂/N₂Carrying out hydroxyl oxidation treatment on the mixed gas for 4-5h;

wherein the grafting treatment is that ZrC particles are placed in a solution of 30-40 mL of toluene and 15-17 mmol of dimethyl azodiisobutyrate under the protection of nitrogen and at 80-85^oStirring and reacting for 3-4h under C;

the hydrolysis treatment is to soak the treated ZrC in 3-5wt.% H₂In an aqueous solution of SO4, a ZrC dispersion was prepared.

2. The nickel plating solution for aluminum alloy according to claim 1, wherein the process conditions for the electroplating treatment of the nickel plating solution for aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 50-60 ℃; electroplating nickel by using the aluminum alloy subjected to zinc dipping treatment as a cathode and a nickel plate as an anode under the condition that the current density is 5-12A/dm 2.

3. The nickel plating solution for aluminum alloy according to claim 1, wherein the alkaline degreasing solution is 10-20wt.% NaOH, and the treatment time is 15-20 min.

4. The nickel plating solution for aluminum alloys according to claim 1, wherein the pickling is 20 to 30wt.% nitric acid, 5 to 10wt.% hydrofluoric acid, and the treatment time is 30 to 50 seconds.

5. The nickel plating solution for aluminum alloy according to claim 1, wherein the ultrasonic treatment is ultrasonic treatment of ZrC in 40-50mL of methanol for 30-60 min.

6. The nickel plating solution for aluminum alloy according to claim 1, wherein a deionized water wash and 50 to 70 degrees centigrade are provided between the oxyhydroxide treatment and the graft treatment^oAnd C, hot air drying treatment.

7. The nickel plating solution for aluminum alloys according to claim 1, wherein centrifugation and toluene washing are provided between the grafting treatment and the hydrolysis treatment, and the number of times of toluene washing is 4 to 5.

8. The nickel plating solution for aluminum alloy according to claim 1, wherein the aluminum alloy is subjected to degreasing, washing, activation, washing, and zincing.

9. The nickel plating solution for aluminum alloy according to claim 8, wherein the degreasing is 50 to 60g/LNaOH, 20 to 40g/LNa2CO3, 20 to 30g/LNa₃PO₄At a temperature of 80-90 deg.C^oC; the activation is 15-18 wt.% of dilute nitreSoaking in acid solution for 30-50 s.

10. The nickel plating solution for aluminum alloy according to claim 8, wherein the zincating solution is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric chloride, 30g/L potassium sodium tartrate, NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

Technical Field

The invention relates to the technical field of surface modification of metal materials, in particular to an electroplating solution for Ni-ZrC composite nickel plating on the surface of an aluminum alloy.

Background

The aluminum alloy has the advantages of light weight, high mechanical strength, easy processing and the like, but the application range and the service life of the aluminum alloy are influenced by the defects of low hardness, poor wear resistance and the like. Electrodeposition of a metal-based composite coating containing second phase particles on the surface of an aluminum alloy can overcome the above problems. Among them, the nickel-based composite plating layer is widely studied, and the added particles are different in function. For example, the hardness of the coating can be improved by adding hard particles such as SiC, A12O3 and diamond, and the friction factor of the coating can be reduced by adding solid lubricating particles such as polytetrafluoroethylene, hexagonal boron nitride, carbon nano tubes, MoS2, WS2 and graphite.

For example, CN202010492650 provides a method for pulse electrodeposition of Ni-SiC composite plating on aluminum alloy surface, wherein the electroplating solution comprises: sodium citrate, disodium ethylene diamine tetraacetate, nickel sulfate, nickel chloride, boric acid, silicon carbide particles and a surfactant sodium stearate; wherein the pH of the electroplating solution is 5-6; mechanically stirring in the electrodeposition process; the current density of the electrodeposition is 15-22A/dm 2. The method can obtain the Ni-SiC composite coating which is refined, compact, uniformly dispersed and high in silicon carbide content, solves the technical problem of poor wear resistance of the aluminum alloy, and can effectively protect the aluminum alloy sample by the Ni-SiC composite coating which is high in binding force, high in silicon carbide hard particle content, uniformly distributed, high in hardness and good in wear resistance.

CN99113478 discloses a nickel-ceramic (Ni-SiC) composite electroplating process for inner wall of aluminum alloy engine cylinder, and the component of electroplating solution is nickel sulfate (NiSO)₄-7H₂O) 410-500g/L, nickel chloride (NiCl)₂) 5-9g/L, boric acid (H)₃BO₃) 41-60g/L, 50-100g/L of silicon carbide (SiC), 1-3g/L of stress relieving agent and 0.1-0.3g/L of dispersing agent. The invention has good effect, the engine cylinder does not need maintenance running-in period, the engine cylinder is durable, the exhaust emission is greatly reduced compared with the national standard, the cold starting performance is improved by 85 percent compared with the national standard, the power is stably improved, and the application prospect is very wide.

CN 105506526A is a method for preparing Ni-SiC composite plating on the surface of aluminum alloy. The cathode type surfactant sodium dodecyl sulfate adopted by the invention is replaced by the anode type surfactant cetyl trimethyl ammonium bromide. According to the invention, the concentration of an anode activator NiCl2 is increased, the current density and the concentration of silicon carbide in a plating solution are reduced, a refined and compact composite plating layer can be obtained at the plating rate of 1-2 μm/min, the silicon carbide is fully dispersed by adopting air stirring, the air volume flow is 4-7L/min, and the CTAB is added to improve the wettability of the silicon carbide, so that the refined and compact composite plating layer with uniformly dispersed silicon carbide and high content can be obtained. The invention solves the technical problem of poor tensile and wear resistance of the aluminum alloy, and can prepare the Ni-SiC composite coating with good bonding force, high content of silicon carbide hard particles, uniform distribution, high hardness and good wear resistance on the surface of the aluminum alloy.

CN200810042319 discloses a preparation method of a composite coating aluminum alloy wear-resistant part, which comprises the following steps: (1) pretreating the surface of the aluminum alloy substrate; (2) performing secondary galvanizing process treatment, namely galvanizing the surface of the aluminum alloy substrate to prepare a Zn transition layer; (3) preparing a Ni-TiN ceramic layer by a high-speed electric spray plating method, washing and drying; the plating solution is a basic plating solution which is a plating solution capable of depositing nickel, and contains 2-10 g/L nano-scale or micro-nano-scale TiN particles and a proper amount of polymer dispersant; (4) and (5) plasma arc scanning strengthening treatment. The composite plating aluminum alloy wear-resistant part obtained by the invention has excellent wear resistance and corrosion resistance, and the composite plating and the aluminum alloy matrix have high binding force; the preparation method is simple to operate, has low cost and can realize industrial production.

From the above documents, it is obvious that the following problems exist in the composite plating process:

(1) the existing composite plating technology considers the technical problem of improving the water solubility of inorganic particles by surface treatment.

(2) The current major methods of dispersing inorganic particles in plating baths focus on ultrasonic dispersion, mechanical agitation, or dispersant dispersion.

Disclosure of Invention

Based on the technical problems, the invention provides a nickel plating solution for an aluminum alloy, through which a Ni-ZrC layer can be compositely plated on the surface of the aluminum alloy, the ZrC can be highly dispersed in the plating solution, the stabilization time is long, and the ZrC can be uniformly dispersed in a plating layer under the condition of high concentration of ZrC, so that the wear resistance, corrosion resistance and hardness of the plating layer are effectively improved.

The plating solution comprises 300g/L of nickel sulfate 250-.

The preparation process of the ZrC dispersion liquid comprises the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment on the nano-particles.

Wherein the hydroxyl oxidation treatment is to place the ZrC particles after ultrasonic treatment in 30-35wt.% NaOH, 100-^oC, refluxing, and introducing 3-5vol₂/N₂Carrying out hydroxyl oxidation treatment on the mixed gas for 4-5 h.

Wherein the grafting treatment is that ZrC particles are placed in a solution of 30-40 mL of toluene and 15-17 mmol of dimethyl azodiisobutyrate under the protection of nitrogen and at 80-85^oStirring and reacting for 3-4h under C.

The hydrolysis treatment is to soak the treated ZrC in 3-5wt.% H₂In an aqueous solution of SO4, a ZrC dispersion was prepared.

Wherein the process conditions of the nickel plating solution for the aluminum alloy electroplating treatment are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 50-60 ℃; electroplating nickel by using the aluminum alloy subjected to zinc dipping treatment as a cathode and a nickel plate as an anode under the condition that the current density is 5-12A/dm 2.

Wherein the alkali degreasing fluid is 10-20wt.% NaOH, and the treatment time is 15-20 min.

Wherein the acid cleaning is 20-30wt.%, 5-10% hydrofluoric acid, and the treatment time is 30-50s;

wherein the ultrasonic treatment is that ZrC is put into 40-50mL of methanol for ultrasonic treatment, and the treatment time is 30-60 min.

Wherein deionized water washing and 50-70 of deionized water washing are arranged between the hydroxyl oxidation treatment and the grafting treatment^oAnd C, hot air drying treatment.

Wherein centrifugation and toluene washing treatment are arranged between the grafting treatment and the hydrolysis treatment, and the toluene washing times are 4-5.

Wherein the aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 50-60g/LNaOH, 20-40g/LNa2CO3, 20-30g/LNa₃PO₄At a temperature of 80-90 deg.C^oC; soaking the activated carbon in a dilute nitric acid solution of 15-18 wt.% for 30-50s; .

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

The invention needs to carry out surface pretreatment on the aluminum alloy, the treatment method is the key of the binding force of the plating layer and the base material, and the pretreatment process comprises the following steps: degreasing, washing, activating, washing and zinc dipping, wherein the degreasing and the activating are conventional effects, and the zinc dipping is a key step, and only the zinc dipping is described here.

As known by those skilled in the art, aluminum can be volatilized to remove electrons, when the aluminum is immersed in a plating solution, a displacement reaction is immediately carried out with metal ions, so that a contact plating layer is formed on the surface of a workpiece, the plating layer is loose and rough, and the bonding strength with a substrate is poor, so that an intermediate layer with better bonding force needs to be formed on the surface of the aluminum alloy before plating so as to avoid direct contact of aluminum and the plating solution, and researches show that the degree of the displacement reaction is not too severe because the electrode potentials of Zn and Al are relatively close, namely, a zinc layer is a good transition layer of electroplating and chemical plating.

The zincing of the aluminum article is essentially displacement deposition, i.e. the potential generated on the surface of the aluminum article by chemical reaction with the zincating solution, in order to reduce the surface activity of the aluminum article, prevent the aluminum from oxidizing and prevent the aluminum article from being plated with metal

The ions are replaced, meanwhile, the natural oxide film can be removed by zinc dipping, the aluminum workpiece can be prevented from being formed again before electroplating, and when the aluminum workpiece is dipped into the zinc dipping solution, the following reactions mainly occur:

Al₂O₃+2NaOH=2NaAlO₂+H₂O；

2Al+3[ZnO2]^2-+2H2O=3Zn+2[AlO2]^-+4OH^-。

the zinc dipping treatment liquid of the invention is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature and 60s of immersion time, wherein the zinc immersion liquid can be used for primary zinc immersion, or can be used for deplating a primary zinc immersion layer and then carrying out secondary zinc immersion, the secondary zinc immersion liquid is completely the same as the primary zinc immersion liquid, and the effect of activating a zinc intermediate layer through the secondary zinc immersion is better.

The plating solution comprises 300g/L of nickel sulfate 250-.

The nickel sulfate and the nickel chloride are main salts, the internal stress of nickel can be obviously increased due to the existence of chloride ions, so that the main components are the nickel sulfate, the boric acid is a buffering agent, the pH value of the plating solution is maintained to be 4.1-4.5, hydroxide is easily generated if the pH value is too high, the nickel hydroxide is mainly precipitated, the precipitate is coated in the plating layer, the physicochemical property of the plating layer is not facilitated, the pH value is too low, the acidity fluctuation of the plating solution is large, pinholes are easily generated, and meanwhile, due to the addition of proper boric acid, fine plating layer crystallization is favorably obtained, and scorching is not easily caused.

The appearance effect of the plating layer can be effectively improved through the brightening agent, wherein benzene sulfonic acid is used as a main brightening agent, butynediol is used as the brightening agent, and sodium ethylene sulfonate is used as an auxiliary brightening agent, the combination of the brightening agents is favorable for obtaining mirror surface gloss appearance, the surface of the plating layer is smooth, the friction coefficient is low as shown in a surface topography diagram of figure 6, and the mechanical property of the plating layer is more beneficial as shown in figure 5.

The composite plating of the invention selects the inorganic nano-particles as zirconium carbide, the zirconium carbide belongs to a NaCl type face-centered cubic structure, for a common FCC structure crystal, the sliding plane is a (111) plane, in a NaCl type structure formed by ZrC crystals, the atomic planes parallel to the (111) are the same metal (Zr) atomic plane and a C atomic plane, namely the distance between every two adjacent atomic planes of Zr, C, Zr and C is a/6, namely half of the distance between every two adjacent Zr atomic planes, because the adjacent Zr atomic planes and the C atomic planes are bonded by the strongest Zr-C bond and the strongest bond is symmetrically distributed, the bond distance must be destroyed on the (111) plane to slide the strongest Zr-C bond, the most difficult sliding is realized, and the ultrahigh hardness is shown on the macroscopic level, the zirconium carbide is more suitable to be used as an inorganic additive particle, the ZrC in the plating layer can directly prevent the movement of dislocation or the grain boundary stabilization and the subgrain boundary, the slippage or climbing of the movable dislocation is limited, so that the abrasion resistance and the strength of the material can be improved.

However, zirconium carbide is an inorganic particle, the surface has almost no hydrophilic group, and the ZrC nanoparticles of the present invention have a size of 30 to 60nm, as known to those skilled in the art, for the superfine particles with small size and high surface energy, and the particles have much adhesive force, so the agglomeration phenomenon of the powder is serious, especially in the solution, agglomeration is more obvious and cannot be dispersed at all, and stirring, ultrasonic or pulse plating in the electroplating process is only relied on, so that the ZrC solution cannot be highly dispersed, and the technical personnel in the field know, in the actual electroplating process, stirring or electrode movement is easy to realize, the cost performance of electroplating by applying ultrasonic waves or pulses is extremely poor, the effect is inferior to the dispersion effect in a laboratory when the electroplating solution is used in actual production, the invention can effectively improve the dispersity of ZrC in the solution and realize uniform dispersion by carrying out surface treatment on ZrC.

The ZrC treatment process mainly comprises alkaline washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, washing drying, grafting treatment, centrifugal washing and hydrolysis treatment.

The alkali washing is used for removing grease on the surface of the commercial ZrC nano powder.

The acid cleaning is mainly used for removing impurities and oxides in the ZrC powder.

The ZrC particles are placed in 30-35wt.% NaOH, 100-^oC, refluxing, and introducing 3-5vol₂/N₂Carrying out hydroxyl oxidation treatment on the mixed gas for 4-5h, introducing hydrophilic oxygen-containing groups such as-O-, -OH and the like on the ZrC surface through reflux and oxygen treatment, wherein the oxygen-containing groups can simply improve the dispersibility of the inorganic nanoparticles, and then carrying out grafting on the surface of the inorganic nanoparticles, wherein the grafting agent is used for treating ZrC particles in 30-40 mL of toluene and 15-17 mmol of dimethyl azodiisobutyrate solution under the protection of nitrogen and at 80-85^oStirring and reacting for 3-4h under C;

under the protection of nitrogen and the heating condition, N is decomposed to form two free radicals^.N-C(CH₃)₂COOCH₃-COOCH which is bonded with oxygen group on ZrC surface and grafted with inorganic particle surface and drifts outside₃The water solubility of the ZrC is high, so that the dispersity of the ZrC in the solution is effectively improved through the hydrophilic effect of COOCH3 similar to a surfactant and the steric hindrance effect of a long chain of the COOCH 3.

furthermore-COOCH₃The ZrC is ester per se, a certain hydrolysis effect can be generated in the grafting process, but the hydrolysis is not complete, and in order to effectively improve the anisotropic stability of the ZrC, the ZrC is soaked in a sulfuric acid solution to be completely hydrolyzed to obtain-NC (CH)₃)₂COOCH₃The bond, the stability and the acidity thereof are more suitable for being used as composite plating inorganic particles, and further high-efficiency dispersion effect is obtained.

As shown in figure 1, after alkali washing, acid washing and ultrasonic treatment (1) are carried out on ZrC, the surface of the ZrC is clean and free of impurities, the oxygen content is 0.89%, an oxygen-containing group (2) is introduced on the surface primarily through hydroxyl oxidation treatment, so that the oxygen content of the ZrC is increased and is placed at 11.93% (3), through subsequent grafting dimethyl azodiisobutyrate and hydrolysis treatment, the hydrophilic oxygen content of the surface is further increased to 18.92% of the oxygen content, the increase of the oxygen content is closely related to the dispersibility of the ZrC in water, and the higher the oxygen content, the higher the hydrophilic performance and the higher the dispersity in water are.

The beneficial technical effects are as follows:

(1) the aluminum alloy substrate is treated by degreasing, washing, activating, washing and zinc dipping, and a layer of zinc is chemically plated on the aluminum alloy substrate, wherein the zinc can effectively enhance the bonding force between the plating and the Ni-ZrC.

(2) The stability of the ZrC solution can be effectively improved through alkaline washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment, the ZrC solution can be suspended for a long time without sedimentation, the sedimentation time in water is more than 9 days, and the sedimentation time in nickel plating solution is approximately equal to 7 days.

(3) ZrC is highly dispersed in the nickel plating layer, and the corrosion resistance, hardness and wear resistance of the plating layer are effectively improved.

Attached drawings of the specification

FIG. 1 shows ZrC after alkali washing, acid washing and ultrasonic processing of ZrC in step (1); (2) carrying out hydroxyl oxidation treatment; (3) oxygen content after hydrolysis treatment.

FIG. 2 is a dispersion sedimentation optical diagram of the composite plating solution prepared in example 2 of the present invention.

FIG. 3 is a diagram showing a comparative example of ZrC prepared in example 2 of the present invention before and after bath dispersion.

FIG. 4 is an SEM cross-sectional view of a coating of the present invention.

FIG. 5 is a friction coefficient chart of the coating of the present invention.

FIG. 6 is a SEM image of the surface topography of the coating of the present invention.

Detailed Description

Example 1

The nickel plating solution for the aluminum alloy comprises 250g/L of nickel sulfate, 30g/L of nickel chloride, 30g/L of boric acid, 1g/L of benzenesulfonic acid main brightener, 0.2g/L of butynediol inferior brightener, 0.1g/L of sodium ethylene sulfonate auxiliary brightener, 0.01g/L of sodium dodecyl sulfate and 5g/L of ZrC dispersion liquid.

The preparation process of the ZrC dispersion liquid comprises the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment on the nano-particles.

The alkali degreasing fluid is 10wt.% NaOH, and the treatment time is 15 min.

The acid wash was 20wt.% nitric acid, 5wt.% hydrofluoric acid, and the treatment time was 30 s.

And the ultrasonic treatment is that ZrC is put into 40mL of methanol for ultrasonic treatment, and the treatment time is 30 min.

The hydroxyl oxidation treatment is to place the ultrasonically treated ZrC particles in 30wt.% NaOH, 100^oRefluxing under C, and introducing 3vol₂/N₂The mixed gas is subjected to hydroxyl oxidation treatment for 4 hours.

Then, deionized water washing and 50^oAnd C, hot air drying treatment.

The grafting treatment is to place ZrC particles in 30mL of toluene and 15mmol of dimethyl azodiisobutyrate solution under the protection of nitrogen at 80 DEG^oThe reaction was stirred for 3h under C.

There were centrifugation and toluene washing treatments, the number of which was 4.

The water isThe solution treatment is to soak the treated ZrC in 3wt.% H₂In an aqueous solution of SO4, a ZrC dispersion was prepared.

The aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 50g/LNaOH, 20g/LNa2CO3, 20g/LNa₃PO₄Temperature 80 of^oC; in which a dilute nitric acid solution activated to 15wt.% was soaked for 30 s.

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

The process conditions of the nickel plating solution for the aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 5 ℃; the zinc-dipped aluminum alloy was used as a cathode, and a nickel plate was used as an anode, and the electrolytic nickel plating was performed at a current density of 5A/dm 2.

Example 2

The nickel plating solution for the aluminum alloy comprises 275g/L nickel sulfate, 35g/L nickel chloride, 32.5g/L boric acid, 1.5g/L benzenesulfonic acid main brightener, 0.3g/L butynediol inferior brightener, 0.15 g/L sodium vinyl sulfonate auxiliary brightener, 0.015 g/L sodium dodecyl sulfate and 15g/L ZrC dispersion liquid. The preparation process of the ZrC dispersion liquid comprises the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment on the nano-particles.

The alkali degreasing fluid is 15wt.% NaOH, and the treatment time is 15-20 min.

The acid wash was 25wt.% nitric acid, 7.5wt.% hydrofluoric acid, and the treatment time was 40 s.

And the ultrasonic treatment is that ZrC is placed in 40-50mL of methanol for ultrasonic treatment, and the treatment time is 45 min.

The hydroxyl oxidation treatment is to place the ultrasonically treated ZrC particles in 32.5wt.% NaOH, 102.5^oRefluxing under C, and introducing 4vol₂/N₂The mixed gas is subjected to hydroxyl oxidation treatment for 4.5 h.

Then, deionized water washing and 60^oAnd C, hot air drying treatment.

The grafting treatment is to place ZrC particles in 35 mL of toluene and 16 mmol of dimethyl azodiisobutyrate solution under the protection of nitrogen at 82.5^oThe reaction was stirred for 3.5h under C.

The method comprises the steps of centrifugation and toluene washing, wherein the number of times of toluene washing is 4-5.

The hydrolysis treatment is to soak the treated ZrC in 4wt.% H₂In an aqueous solution of SO4, a ZrC dispersion was prepared.

The aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 55g/LNaOH, 30g/LNa2CO3 and 25g/LNa₃PO₄Temperature 85 deg.C^oC; in which it was soaked for 40s in a dilute nitric acid solution with an activation of 16.5 wt.%.

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

The process conditions of the nickel plating solution for the aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 55 ℃; the zinc-dipped aluminum alloy was used as a cathode, and a nickel plate was used as an anode, and the electrolytic nickel plating was performed at a current density of 8.5A/dm 2.

Example 3

The nickel plating solution for the aluminum alloy comprises 300g/L of nickel sulfate 250-. The preparation process of the ZrC dispersion liquid comprises the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment on the nano-particles.

The alkali degreasing fluid is 20wt.% NaOH, and the treatment time is 20 min.

The acid wash was 30wt.% nitric acid, 10wt.% hydrofluoric acid, and the treatment time was 50 s.

And the ultrasonic treatment is that ZrC is put into 50mL of methanol for ultrasonic treatment, and the treatment time is 60 min.

The hydroxyl oxidation treatment is to place the ultrasonically treated ZrC particles in 35wt.% NaOH, 105^oRefluxing under C, and introducing 5vol₂/N₂The mixed gas is subjected to hydroxyl oxidation treatment for 5 hours.

Then, deionized water washing and 70^oAnd C, hot air drying treatment.

The grafting treatment is to place ZrC particles in 40mL of toluene and 17 mmol of dimethyl azodiisobutyrate solution under the protection of nitrogen at 85 DEG^oThe reaction was stirred for 4h under C.

The method comprises the steps of centrifugation and toluene washing, wherein the number of times of toluene washing is 4-5.

The hydrolysis treatment is to soak the treated ZrC in 5wt.% H₂In an aqueous solution of SO4, a ZrC dispersion was prepared.

The aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 60g/LNaOH, 40g/LNa2CO3, 30g/LNa₃PO₄Temperature 90 of^oC; in which a dilute nitric acid solution with an activation of 18 wt.% was soaked for 50 s.

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

The process conditions of the nickel plating solution for the aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 60 ℃; the zinc-dipped aluminum alloy is used as a cathode, a nickel plate is used as an anode, and the electroplating nickel is carried out under the condition that the current density is 12A/dm 2.

Comparative example 1

The nickel plating solution for the aluminum alloy comprises 275g/L of nickel sulfate, 35g/L of nickel chloride, 32.5g/L of boric acid, 1.5g/L of benzenesulfonic acid main brightener, 0.3g/L of butynediol inferior brightener, 0.15 g/L of sodium vinyl sulfonate auxiliary brightener and 0.015 g/L of sodium dodecyl sulfate.

The aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 55g/LNaOH, 30g/LNa2CO3 and 25g/LNa₃PO₄Temperature 85 deg.C^oC; in which it was soaked for 40s in a dilute nitric acid solution with an activation of 16.5 wt.%.

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

The process conditions of the nickel plating solution for the aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 55 ℃; the zinc-dipped aluminum alloy was used as a cathode, and a nickel plate was used as an anode, and the electrolytic nickel plating was performed at a current density of 8.5A/dm 2.

Comparative example 2

The nickel plating solution for the aluminum alloy comprises 275g/L nickel sulfate, 35g/L nickel chloride, 32.5g/L boric acid, 1.5g/L benzenesulfonic acid main brightener, 0.3g/L butynediol inferior brightener, 0.15 g/L sodium vinyl sulfonate auxiliary brightener, 0.015 g/L sodium dodecyl sulfate and 15g/L ZrC dispersion liquid. The preparation process of the ZrC dispersion liquid comprises the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing and ultrasonic treatment on the nano-particles.

The alkali degreasing fluid is 15wt.% NaOH, and the treatment time is 15-20 min.

The acid wash was 25wt.% nitric acid, 7.5wt.% hydrofluoric acid, and the treatment time was 40 s.

And the ultrasonic treatment is that ZrC is placed in 40-50mL of methanol for ultrasonic treatment, and the treatment time is 45 min.

The aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 55g/LNaOH, 30g/LNa2CO3 and 25g/LNa₃PO₄Temperature 85 deg.C^oC; in which it was soaked for 40s in a dilute nitric acid solution with an activation of 16.5 wt.%.

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature, immersion time 60 s.

The process conditions of the nickel plating solution for the aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 55 ℃; the zinc-dipped aluminum alloy was used as a cathode, and a nickel plate was used as an anode, and the electrolytic nickel plating was performed at a current density of 8.5A/dm 2.

Comparative example 3

The nickel plating solution for the aluminum alloy comprises 275g/L nickel sulfate, 35g/L nickel chloride, 32.5g/L boric acid, 1.5g/L benzenesulfonic acid main brightener, 0.3g/L butynediol inferior brightener, 0.15 g/L sodium vinyl sulfonate auxiliary brightener, 0.015 g/L sodium dodecyl sulfate and 15g/L ZrC dispersion liquid. The preparation process of the ZrC dispersion liquid comprises the following steps:

selecting 30-60nm ZrC nano-particles, and sequentially carrying out alkali washing, acid washing, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment on the nano-particles.

The alkali degreasing fluid is 15wt.% NaOH, and the treatment time is 15-20 min.

The acid wash was 25wt.% nitric acid, 7.5wt.% hydrofluoric acid, and the treatment time was 40 s.

And the ultrasonic treatment is that ZrC is placed in 40-50mL of methanol for ultrasonic treatment, and the treatment time is 45 min.

The hydroxyl oxidation treatment is to place the ultrasonically treated ZrC particles in 32.5wt.% NaOH, 102.5^oRefluxing under C, and introducing 4vol₂/N₂The mixed gas is subjected to hydroxyl oxidation treatment for 4.5 h.

Then, deionized water washing and 60^oAnd C, hot air drying treatment.

The aluminum alloy is subjected to oil removal, water washing, activation, water washing and zinc immersion treatment.

Wherein the oil removal is 55g/LNaOH, 30g/LNa2CO3 and 25g/LNa₃PO₄Temperature 85 deg.C^oC; in which it was soaked for 40s in a dilute nitric acid solution with an activation of 16.5 wt.%.

Wherein the zinc immersion treatment liquid is 5g/LZnO, 95g/LNaOH, 1.5g/L ferric trichloride, 30g/L potassium sodium tartrate and NiCl₂ 22 g/L，NaF1 g/L，NaNO₃5g/L, room temperature,the immersion time was 60 s.

The process conditions of the nickel plating solution for the aluminum alloy are as follows: the pH value is 4.1-4.5, and the temperature of the electroplating solution is 55 ℃; the zinc-dipped aluminum alloy was used as a cathode, and a nickel plate was used as an anode, and the electrolytic nickel plating was performed at a current density of 8.5A/dm 2.

As shown in the table, the ZrC nano particles of the invention are subjected to alkali cleaning, acid cleaning, ultrasonic treatment, hydroxyl oxidation treatment, grafting treatment and hydrolysis treatment, so that the hydrophilic performance of the ZrC nano particles is effectively improved, the plating solution obtained by using the treated ZrC nano particles as composite plating inorganic particles to prepare the plating solution is obviously deposited in about 7 days, as shown in figure 2, the suspension performance test results of ZrC particles obtained by using ZrC particles treated in comparative example 1 and ZrC particles treated in examples 3, 2 and 1 to stand in water for 4 days are sequentially performed from left to right, so that the excellent hydrophilic performance of the ZrC in the solution is obviously obtained, as shown in figure 3, the left graph is obviously agglomerated, and the dispersity is obviously increased after the treatment.

The prepared coating material is compact in nickel composite coating, particles are in a nanometer level and cannot be obviously observed, and the small particles are uniformly dispersed in the coating through the enlarged diagram of figure 4.

In contrast, when the ZrC particles are subjected to only ultrasonic mechanical treatment, which is physical separation, the high specific surface energy of the particles cannot be reduced, and obvious sedimentation occurs within 30min, in contrast, when the hydroxyl oxidation treatment is carried out, the hydrophilic performance is improved, but the sedimentation of the plating solution occurs within about 1 day.

Then, hardness and wear rate tests are carried out on the plating layer prepared by the plating solution of the invention, the composite plating material prepared in the example 2 has high hardness and low wear rate, the influence of the hydroxyl oxidation treatment, the grafting treatment and the hydrolysis treatment on the dispersibility of the plating solution is verified, and if the inorganic particles cannot be effectively dispersed, the hardness and the wear rate have obvious influence.

And then, carrying out electrochemical corrosion performance test on the plating layer, wherein the more positive the self-corrosion potential is, the smaller the corrosion current density is, the slower the corrosion speed is, and the better the corrosion resistance is, and the corrosion potential and the corrosion current density of the composite plating layer prepared by the invention both show the stronger corrosion resistance of the plating layer.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.