Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for directly electroplating metal zinc on surface of aluminum or aluminum alloy

A technology for electroplating metal on the surface of aluminum alloy, which is applied in the field of direct electroplating metal zinc on the surface of aluminum or aluminum alloy, which can solve the problems of cumbersome steps, rough crystallization, poor bonding force of the substrate, etc., and achieve the effect of reducing costs and good bonding force of the coating

Inactive Publication Date: 2016-04-06
宏正(福建)化学品有限公司
View PDF3 Cites 14 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The chemical properties of metal aluminum are relatively active, and its affinity with oxygen is strong. It is very easy to form an oxide film on its surface in the atmosphere. Even after the oxide film is removed, a new oxide film will be quickly regenerated, which seriously affects the coating and coating. The binding force of the substrate aluminum; aluminum and its aluminum alloys are amphoteric metals, which cannot be stabilized in acid-base solutions. At the same time, the electrode potential of aluminum is relatively negative, about (-1.66V), and it is easy to lose electrons. It can immediately undergo substitution reaction with a variety of metal ions to form a contact layer. This kind of coating is loose and porous, with rough crystals and poor bonding with the substrate, which hinders the bonding between the coating and the substrate; the expansion coefficient of aluminum is larger than that of many metal coatings , when the temperature difference changes greatly, due to the inconsistent expansion coefficients of the substrate and the coating, it is easy to generate internal stress and damage the coating; cast aluminum parts have sand holes, casting holes, bubbles, etc., and the bath liquid and hydrogen are easy to remain in the electroplating, causing chemical and electrical damage. Chemical corrosion, resulting in blistering and peeling of the coating
[0003] Aluminum and its aluminum alloys need a special pretreatment process before electroplating. At present, the common process in the industry is: degreasing and rust removal → water washing → zinc dipping → two water washings → zinc stripping → two water washings → electroless nickel plating → two Water washing→nickel electroplating, this method has cumbersome steps, short service life of immersion plating solution, and high cost

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Embodiment 1: The aluminum alloy sample is polished to remove rust and scale on the surface to obtain a flat and smooth surface. Immerse in 60°C, 100g / L alkaline degreasing solution for 3 minutes, wash with hot water, and then rinse with two flows of cold water countercurrently. After corroding in 30g / L alkaline corrosion solution for 15 seconds, rinse with two countercurrent flowing cold water. After observing the continuous water film on the surface of the aluminum alloy, pickling is carried out. The concentration of the pickling solution is 750ml / L. Two flows of cold water are rinsed in countercurrent, and then activated. The concentration of the activation solution is 30ml / L. The aluminum alloy after activation and washing is electro-galvanized. The composition of the zinc electroplating solution is zinc sulfate 55g / L, sodium sulfate 50g / L, aluminum sulfate 25g / L, gluconic acid 40g / L, ammonium citrate 30g / L, sodium pyrophosphate 160g / L, dextrin 1g / L, Connect direct...

Embodiment 2

[0031] Embodiment 2: The aluminum alloy sample is polished to remove rust and scale on the surface to obtain a flat and smooth surface. Immerse in 65°C, 95g / L alkaline degreasing solution for 2 minutes, wash with hot water and then rinse with cold water countercurrently in two streams. After corroding in 35g / L alkaline corrosion solution for 12 seconds, rinse with two countercurrent flowing cold water. After observing the continuous water film on the surface of the aluminum alloy, pickling is carried out. The concentration of the pickling solution is 700ml / L. Two flowing cold waters are rinsed in countercurrent, and then activated. The concentration of the activation solution is 35ml / L. The aluminum alloy after activation and washing is electro-galvanized. The composition of the electroplating zinc solution is zinc sulfate 58g / L, sodium sulfate 30g / L, boric acid 30g / L, sodium gluconate 130g / L, potassium tartrate 50g / L, hexamethylenediamine tetramethylene phosphonic acid 10g / L,...

Embodiment 3

[0036] Embodiment 3: The aluminum alloy sample is polished to remove rust and scale on the surface to obtain a flat and smooth surface. Immerse in an alkaline degreasing solution at 70°C for 1 minute, wash with hot water, then rinse with countercurrent flow of cold water and spray. After corroding in 40g / L alkaline corrosion solution for 10 seconds, rinse with countercurrent flow of cold water. After observing the continuous water film on the surface of the aluminum alloy, pickling is carried out, and then activated. The concentration of the activation solution is 40ml / L, and the aluminum alloy after activating for 15s is electro-galvanized after water washing. The composition of the zinc electroplating solution is zinc chloride 28g / L, ammonium chloride 190g / L, oxalic acid 25g / L, sodium ethylenediamine tetramethylene phosphonate 15g / L, sodium acetate 10g / L, thiourea 0.5ml / L , the current waveform is a single pulse waveform, and the cathode current density is 0.8~1.6A / dm 2 . ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a method for directly electroplating metal zinc on the surface of aluminum or aluminum alloy. The technological process includes the steps firstly, pre-treatment is performed, wherein degreasing, hot water cleaning, countercurrent rinsing or sprinkling of two paths of flowing cold water, alkali corrosion, countercurrent rinsing or sprinkling of two paths of flowing cold water, acid pickling, countercurrent rinsing or sprinkling of two paths of flowing cold water, activating and countercurrent rinsing or sprinkling of two paths of flowing cold water are performed; secondly, zinc electroplating is performed, wherein electroplating is performed on aluminum alloy, countercurrent rinsing or sprinkling of two paths of flowing cold water is performed, zinc deplating is performed, and countercurrent rinsing of flowing cold water is performed; thirdly, alkaline copper or nickel electroplating is performed, wherein dark nickel, semi-bright nickel or alkaline copper electroplating is performed, countercurrent rinsing or sprinkling of two paths of flowing cold water is performed, and subsequent electroplating is performed till final water washing and drying are performed. Compared with a traditional method, the zinc immersion technology is not needed and is changed into the zinc electroplating technology, the service life of a zinc electroplating solution is greatly longer than that of a zinc immersion solution, cost is reduced, and binding force of a cladding layer is good.

Description

technical field [0001] The invention relates to a method for directly electroplating metal zinc on the surface of aluminum or aluminum alloy. Background technique [0002] Aluminum and its alloys have the advantages of high specific strength, good thermal conductivity and electrical conductivity, as well as plasticity and easy forming, and have been widely used in various industries. The chemical properties of metal aluminum are relatively active, and its affinity with oxygen is strong. It is very easy to form an oxide film on its surface in the atmosphere. Even after the oxide film is removed, a new oxide film will be quickly regenerated, which seriously affects the coating and coating. The binding force of the substrate aluminum; aluminum and its aluminum alloys are amphoteric metals, which cannot be stabilized in acid-base solutions. At the same time, the electrode potential of aluminum is relatively negative, about (-1.66V), and it is easy to lose electrons. It can imme...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/22C25D5/10C25D5/12C25D5/44C25D5/18
CPCC25D3/22C25D5/10C25D5/12C25D5/18C25D5/44
Inventor 叶金堆
Owner 宏正(福建)化学品有限公司