Process for directly electroplating on surface of aluminium or aluminium alloy

An aluminum alloy surface, direct technology, applied in the field of direct electroplating on aluminum or aluminum alloy surface, can solve the problems of poor coating adhesion, high production cost, cumbersome steps, etc., achieve grain refinement, improve adhesion, and simple process operation Effect

Inactive Publication Date: 2006-06-28
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for direct electroplating on the surface of aluminum or aluminum alloy in view of the shortcomings of the existing aluminum alloy electroplating technology, such as cumbersome steps, poor coating adhesion, and high production costs. This method does not require special pretreatment and has simple steps. , the coating has good adhesion and the cost is low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Direct nickel plating on pure aluminum

[0033] The sample uses L3 industrial pure aluminum, the specific steps are as follows:

[0034] 1. Pre-treatment. Using NaOH 250g / L, NaNO 3 460g / L, CoSO 4 The chemical polishing liquid composed of 1g / L chemically polishes the sample. Temperature 80~95℃, time 2min; wash with water.

[0035] 2. Direct nickel plating. The pre-processed sample is charged into the electroplating tank for electroplating. The composition of the electroplating solution is: NiSO 4 60g / L; Boric acid 25g / L; NaCl 50g / L; Sodium citrate 5g / L; NaF 5g / L; Potassium sodium tartrate 10g / L; pH value 4.5. Adopt pulse current method, current frequency 50Hz; working ratio 30%; current density 2A / dm 2 ; Plating time 20min; room temperature. Wash with water; blow dry.

[0036] Coating quality: uniform, smooth and dense; coating thickness is 12μm.

[0037] The binding force of the sample is tested by the following methods:

[0038] (1) Use a steel knife tip to make parallel a...

Embodiment 2

[0043] Direct nickel plating on hard aluminum alloy

[0044] The sample uses LY-12 hard aluminum alloy, and the specific steps are as follows:

[0045] 1. Mechanical pretreatment: use sandblasting or sandpaper grinding to remove burrs, solid oxides, extrusion lubricants, cutting oils and other foreign matter, reduce surface roughness; water washing;

[0046] 2. Chemical polishing: using NaOH 300g / L, NaNO 3 500g / L, CoSO 4 The chemical polishing liquid composed of 2g / L chemically polished the sample. Temperature 80~95℃, time 3min; water washing;

[0047] 3. Direct nickel electroplating: the pre-treated sample is charged into the electroplating tank for electroplating. The composition of the electroplating solution is: NiSO 4 70g / L; NiCl 2 50g / L; boric acid 20g / L; disodium ethylenediaminetetraacetic acid 10g / L; ammonium bifluoride 5g / L; sodium tartrate 10g / L; pH 4.0. Using DC plating, current density 8A / dm 2 ; Plating time 20min; room temperature. Wash with water; blow dry.

[0048] ...

Embodiment 3

[0054] Direct nickel plating on cast aluminum alloy

[0055] The sample adopts ZL-108 cast aluminum alloy, the specific steps are as follows:

[0056] 1. Mechanical pretreatment: use sandblasting and sandpaper grinding to remove burrs, solid oxides, extrusion lubricants, cutting oil and other foreign matter, reduce surface roughness; water washing;

[0057] 2. Chemical polishing: using NaOH 300g / L, NaNO 3 520g / L, CoSO 4 The chemical polishing liquid composed of 5g / L chemically polishes the sample. Temperature 80~95℃, time 3min; water washing;

[0058] 3. Direct nickel electroplating: the pre-treated sample is charged into the electroplating tank for electroplating. The composition of the electroplating solution is: NiSO 4 80g / L; NiCl 2 20g / L; Boric acid 30g / L; NaCl 30g / L; Sodium fluoride 10g / L; Sodium tartrate 15g / L; Sodium citrate 15g / L; pH value 3.5; Using pulse current method, current frequency 100Hz; working ratio 10 %; current density 3A / dm 2 ; Plating time 20min; room temper...

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Abstract

The invention relates to a aluminum and its alloy surface direct electroplating method. Its features are that the aluminum alloy is no need special pre-processing before electroplating; it is put in bath after chemical polishing; the bath is added complexation film removing film; electroplating is adopted direct current or impulse current; the pulse frequency is 50-100Hz; duty factor is 10%-30%; current density is 2-8A / dm2. The formed plating layer is uniform and compact. The plating layer and the aluminum foundation base have good binding power. The invention overcomes the defect of cockamamie steps, forward product quality and bad plating layer binding in traditional aluminum and its alloy electroplating. It is simple and convenient aluminum and its alloy surface processing method satisfied their high quality surface processing and performance demand.

Description

Technical field [0001] The invention relates to a method for electroplating nickel directly on the surface of aluminum and aluminum alloy. Specifically, the aluminum and aluminum alloy nickel electroplating process of the present invention does not require special pretreatment on the aluminum alloy material, and can be directly electroplated in the plating solution to obtain the plating layer. Background technique [0002] Aluminum and its alloys are one of the most widely used metals, which have the characteristics of good electrical conductivity, fast heat transfer, light specific gravity, high specific strength, and easy forming. However, aluminum and its alloys have shortcomings such as low hardness, non-wearing, prone to intergranular corrosion, and difficult to weld, which affect their application range and service life. Aluminum and its alloys can be endowed with protection-decoration and other functional purposes after electroplating, which can extend the service life and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/30C25D3/12C25D5/44
Inventor 旷亚非周海晖罗胜联戴磊农永光
Owner HUNAN UNIV
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