Double-bottoming electroplating method for nickel-plating magnesium alloy hub

A magnesium alloy and wheel hub technology is applied in the field of double-priming electroplating of nickel-plated magnesium alloy wheels, which can solve the problems of limited anti-corrosion effect, many defects in plating parts, and increased production cost, and achieves good decorative appearance and good anti-peeling performance. , the effect of saving production costs

Inactive Publication Date: 2016-05-04
张颖
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) Magnesium alloy cyanide pre-copper plating process uses highly toxic cyanide, which is harmful to human health and pollutes the environment
Dow process, Norskhydro process and WCM process are unstable, the operating window is narrow, and there are many defects in the plated parts after plating
[0005] (2) The direct electroless nickel plating process of magnesium alloy uses a pretreatment solution containing hexavalent chromium Cr(VI) and hydrofluoric acid, which is harmful to human health and pollutes the environment; the electroless nickel plating solution is a thermodynamically unstable system, and the plating The service life of the liquid is short and the production cost is high
This makes the technological process of magnesium alloy electroplating treatment cumbersome and increases the production cost
Therefore, the electro-galvanized layer is generally used as the final coating on the magnesium alloy, and is no longer electroplated for other combined coatings, and its anti-corrosion effect is limited.
[0007] (4) Electroplating copper directly in pyrophosphate solution after zinc immersion in magnesium alloy is prone to poor bonding between copper coating and magnesium alloy substrate
Because the complexing ability of pyrophosphate ions to copper ions is poor, the potential difference between the magnesium alloy substrate and metallic copper is very large. When copper is electroplated in pyrophosphate solution, the substrate magnesium and copper ions undergo a violent substitution reaction, which makes the copper coating Decreased binding to the substrate
The compactness of the pre-plating layer is not enough, and the plated parts are corroded during acid copper plating
[0008] (5) The magnesium alloy metal coating coating technology reported in the literature is only a laboratory result, and there is no electroplating industrial application of magnesium alloy products; most of the research is concentrated on the pretreatment of magnesium alloy electroplating, and the completeness of magnesium alloy combined electroplating technology has not been proposed. Program

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A kind of double bottom electroplating method of nickel-plated magnesium alloy wheel hub, the method operation steps are as follows:

[0024] 1) Pre-plating treatment: including cleaning, pickling, activation, and then zinc precipitation twice;

[0025] 2) Pre-plating cyanide-free copper primer treatment, wherein the composition and process of the plating solution for pre-plating cyanide-free copper are: copper sulfate 120g / L; sodium ethylenediamine tetramethylene phosphonate 180g / L, potassium tartrate 80g / L L; 2-Mercaptobenzothiazole 0.5g / L, the pH of the plating solution is 8.5; the temperature of the plating solution is 55°C; the plating time is 15min; the cathode current density: 1.4A / dm 2 ;Anode current density: 0.6A / dm 2 ; using gas stirring;

[0026] 3) Pyrophosphate copper plating primer treatment, wherein the composition and process of the pyrophosphate copper plating treatment plating solution are: copper pyrophosphate 120g / L; potassium pyrophosphate 140g / L;...

Embodiment 2

[0029] A kind of double bottom electroplating method of nickel-plated magnesium alloy wheel hub, the method operation steps are as follows:

[0030] 1) Pre-plating treatment: including cleaning, pickling, activation, and then zinc precipitation twice;

[0031] 2) Pre-plating cyanide-free copper primer treatment, wherein the composition and process of the plating solution for pre-plating cyanide-free copper are: copper sulfate 130g / L; sodium ethylenediamine tetramethylene phosphonate 160g / L, potassium tartrate 100g / L L; 2-Mercaptobenzothiazole 0.3g / L, the pH of the plating solution is 9.5; the temperature of the plating solution is 45°C; the plating time is 25min; the cathode current density: 1.2A / dm 2 ;Anode current density: 0.8A / dm 2 ; using gas stirring;

[0032] 3) Pyrophosphate copper plating primer treatment, wherein the composition and process of the pyrophosphate copper plating treatment plating solution are: copper pyrophosphate 100g / L; potassium pyrophosphate 160g / L...

Embodiment 3

[0035] A kind of double bottom electroplating method of nickel-plated magnesium alloy wheel hub, the method operation steps are as follows:

[0036] 1) Pre-plating treatment: including cleaning, pickling, activation, and then zinc precipitation twice;

[0037] 2) Pre-plating cyanide-free copper primer treatment, wherein the composition and process of the plating solution for pre-plating cyanide-free copper are: copper sulfate 125g / L; sodium ethylenediamine tetramethylene phosphonate 170g / L, potassium tartrate 90g / L L; 2-mercaptobenzothiazole 0.4g / L, the pH of the plating solution is 9.0; the temperature of the plating solution is 50°C; the plating time is 20min; the cathode current density: 1.3A / dm 2 ;Anode current density: 0.7A / dm 2 ; using gas stirring;

[0038] 3) Pyrophosphate copper plating primer treatment, wherein the composition and process of the pyrophosphate copper plating treatment plating solution are: copper pyrophosphate 110g / L; potassium pyrophosphate 150g / L; c...

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Abstract

The invention discloses a double-bottoming electroplating method for a nickel-plating magnesium alloy hub. The method includes the following operation steps that firstly, preplating treatment is conducted; secondly, preplating cyanide-free copper bottoming treatment is conducted, wherein a plating solution of preplating cyanide-free copper includes 120-130 g / L of copper sulfate, 160-180 g / L of sodium ethylenediamine tetramethylene phosphonate, 80-100 g / L of potassium tartrate and 0.3-0.5 g / L of 2-mercaptobenzothiazole, according to the technology of the plating solution of the preplating cyanide-free copper, the pH of the plating solution is 8.5-9.5, the temperature of the plating solution is 45-55 DEG C, the electroplating time is 15-25 min, the cathodic current density is 1.2-1.4 A / dm<2>, the anodic current density is 0.6-0.8 A / dm<2>, and gas stirring is adopted; thirdly, pyrophosphate copper plating bottoming treatment is conducted, wherein a plating solution of pyrophosphate copper plating treatment comprises 100-120 g / L of copper pyrophosphate, 140-160 g / L of potassium pyrophosphate, 6-8 mL / L of ammonia water with the concentration of 25-30%, 8-12 g / L of potassium citrate, 15-25 g / L of potassium sodium tartrate, 0.2-0.3 mL / L of a brightening agent and the balance water, according to the technology of the plating solution, the pH of the plating solution is 8.5-9.5, the temperature of the plating solution is 45-55 DEG C, the electroplating time is 25-35 min, the cathodic current density is 1.2-1.4 A / dm<2>, the anodic current density is 0.7-0.9 A / dm<2>, and gas stirring is adopted; and fourthly; nickel electroplating is adopted.

Description

technical field [0001] The invention relates to the field of electroplating, in particular to a double-priming electroplating method for a nickel-magnesium alloy wheel hub. Background technique [0002] Magnesium alloy has excellent properties such as light weight, high specific strength, shock resistance and shock absorption, and is considered to be an excellent substitute for aluminum alloy in the automotive industry. Magnesium alloys are used in the automobile industry, which can reduce the weight of automobiles and is an effective way to reduce energy consumption and exhaust emissions. The wheel hub is one of the parts that account for the largest weight of the vehicle. Using magnesium alloy as the material for manufacturing the wheel hub can achieve the purpose of effectively reducing the weight of the vehicle. At present, wheels made of magnesium alloys have been widely used in motorcycles. However, the chemical properties of magnesium alloy are very active, and its ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/12C25D7/00C25D3/38
CPCC25D5/12C25D3/38C25D7/00
Inventor 张颖
Owner 张颖
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