CN103898572A - Process for plating copper on surface of magnesium alloy shell - Google Patents

Abstract

The invention discloses a process for plating copper on the surface of a magnesium alloy shell. The process comprises the following steps: (1) cleaning: cleaning by using alkali, water and acid in sequence; (2) activating: activating in an activation solution for 5-15 minutes; (3) performing zinc alloy soaking: soaking a magnesium alloy casting in zinc alloy immersion liquid at the temperature of 75-85 DEG C for 10-15 minutes; (4) plating copper: plating under the condition that the pH is 8-8.5, the current density is 3-3.5 A/dm<2>, and the temperature is 35-45 DEG C. By adjusting the zinc immersion liquid and plating solution components for plating copper, the defects in the prior art are overcome, and the bonding force between a plating and a substrate is enhanced.

Description

The technique of a kind of magnesium alloy shell surface electrical copper facing

Technical field

The present invention relates to electroplating technology field, relate in particular to the technique of a kind of magnesium alloy shell surface electrical copper facing.

Background technology

The thermal diffusivity of magnesium alloy is not only high than plastics, and is better than aluminium alloy, and the thermal diffusivity of magnesium alloy is 3.79 × 10 ^-5m ²ps, the thermal diffusivity of aluminium alloy is 3.64 × 10 ^-5m ²ps, and the thermal diffusivity of engineering plastics is 0.The heating of magnesium alloy is faster than aluminium alloy with heat radiation, and engineering plastics cannot be compared especially.Magnesium alloy also has the performance of very high shield electromagnetic interference, is suitable for doing the shell of electronic equipment, is particularly suitable for making the shell of the products such as laptop computer, mobile phone, palm PC, digital camera.

Magnesium alloy has the function of light durable, damping, shielding in a word, and specific tenacity is high, be easy to recycling, cheap feature, can be widely used in the industrial circles such as defence and military, communications and transportation, opticinstrument and electron device.

The subject matter that affects magnesium alloy application is the solidity to corrosion problem of magnesium alloy, and because the current potential of magnesium is very negative, solidity to corrosion is under certain conditions poor, and its range of application is very limited.In order to make full use of, magnesium alloy density is little, the feature of high specific strength and specific rigidity, people are on the one hand constantly improving the solidity to corrosion of magnesium alloy from the aspect such as alloying, thermal treatment, be exactly on the other hand by process for protecting surface seek to improve magnesium alloy anti-corrosion by way of.

There is much technique on magnesium and Mg alloy surface, to form coat, comprise plating, electroless plating, conversion film, anodic oxidation, organic coating, vapor deposition layer etc.Wherein simple effective method is exactly the metal or alloy that plates one deck desired properties by electrochemical method on magnesium and magnesium alloy substrate the most, electroplates.The object that magnesium and Mg alloy surface are electroplated has two: the one, and protection, the 2nd, attractive in appearance, magnesium and Mg alloy surface have protecting decorative coating.Magnesium after plating and magnesium-alloy material are mainly used on the component of high-speed moving object and need to carry on the component of goods and portable product, wherein first-selected Application Areas is the industries such as automobile, motorcycle and bike, next is portable type electronic product, as notebook computer, mobile telephone, walkman etc.

The solution magnesium of comparative maturity and Mg alloy surface corrosion-resistanting decoration treatment technology mainly contain two kinds in the world, first paint spraying, and it two is Metal platings.The former is the traditional method of current Mg alloy surface processing, but Mg alloy surface is required to use under high gloss decoration, wear-resisting, heat-resisting condition, and paint spraying can not meet the demands, and this just need to solve with metal plating.But magnesium alloy is extremely unstable in conventional bath solution, magnesium alloy member can not directly enter tank liquor and electroplate.Conventionally need to carry out pre-treatment to magnesium and Mg alloy surface, then can electroplate with conventional, reach the object to magnesium alloy surface protective decoration.

Magnesium and magnesium alloy plating carry out the standard method that the main U.S. ASTM of employing recommends of pretreated method both at home and abroad at present, are the zinc methods of soaking of Dow company exploitation, and its pre-treatment has adopted soaks zinc and cyanide copper plating technique.Not only complex process of this technology, and adopted poisonous prussiate.United States Patent (USP) 6068938 has been described pyrophosphate electroplating copper after employing electro-galvanizing and has been replaced cyanide electroplating; Domestic also have the pyrophosphate salt of employing to replace prussiate technology; Japanese Patent 59050194 is described after magnesium alloy pre-treatment, adopts the plating solution that contains silicate in the time of copper facing.The homogeneity of above-mentioned these technique electro-coppering coating, planarization and not very good with aspects such as the bonding forces of metallic matrix.

Summary of the invention

The object of the invention is to propose the technique of a kind of magnesium alloy shell surface electrical copper facing, by the adjustment to zincate solution immersion liquid, pre-zinc-plated immersion liquid and copper-plated bath composition, overcome the defect of prior art, make the bonding force of coating and matrix better.

For reaching this object, the present invention by the following technical solutions:

A technique for magnesium alloy shell surface electrical copper facing, described technique comprises the steps:

1) clean: under the condition of 65-75 DEG C, Mg alloy castings is soaked in alkaline wash to 8-10min, alkali lye consists of sodium hydroxide 74-76g/L, sodium phosphate 6-8g/L, surplus is water, then washing; Under the condition of 35-45 DEG C, Mg alloy castings is soaked in tartrate to 40-60s, then washing;

2) activation: Mg alloy castings is activated in activator to 5-15min under the condition of room temperature, then washing; Activation solution consists of citric acid 165-175g/L, NaF200-210g/L, and surplus is water;

3) soak zinc alloy: zincate solution immersion liquid consists of: ZnSO ₄7H ₂o32-36g/L, Na ₄p ₂o ₇10H ₂o160-170g/L, NaF10-12g/L, KF6-8g/L, Na ₂cO ₃8-12g/L, NiSO ₄2-3g/L, phosphatase 11 5-18g/L, surplus is water; Under 75-85 DEG C of condition, Mg alloy castings is soaked to 10-15min in zinc alloy immersion liquid;

4) electro-coppering: described copper-plated plating solution consists of: CuSO ₄40-50g/L, CuCl ₂12-14g/L, K ₂cO ₃55-65g/L, K ₄p ₂o ₇3H ₂o240-260g/L, C ₄h ₄o ₆kNa3H ₂o44-48g/L, K ₂hPO ₄3H ₂o55-65g/L, the hydroxy ethylene two sour 100-110g/L that sees, phytic acid 0.3-0.5g/L, surplus is water; Electroplating technology is: pH is 8-8.5, and current density is 3-3.5A/dm ², temperature is 35-45 DEG C.

The present invention has following technique effect:

By the adjustment to solution composition, make outward appearance light, the bonding force of gained copper coating good, porosity is low, and easy to maintenance.Covering power and the covering power of electroplating solution are good.Adopt the Mg alloy castings after the inventive method copper facing can directly use the bottom that also can be used as follow-up nickel plating, chromium plating.

Embodiment

Embodiment mono-

A technique for magnesium alloy shell surface electrical copper facing, described technique comprises the steps:

1) clean: under the condition of 65-75 DEG C, Mg alloy castings is soaked in alkaline wash to 8min, alkali lye consists of sodium hydroxide 74g/L, sodium phosphate 8g/L, surplus is water, then washing; Under the condition of 35-45 DEG C, Mg alloy castings is soaked in tartrate to 60s, then washing;

2) activation: Mg alloy castings is activated in activator to 5-15min under the condition of room temperature, then washing; Activation solution consists of citric acid 165g/L, NaF210g/L, and surplus is water;

3) soak zinc alloy: zincate solution consists of: ZnSO ₄7H ₂o32g/L, Na ₄p ₂o ₇10H ₂o170g/L, NaF10g/L, KF8g/L, Na ₂cO ₃8g/L, NiSO ₄3g/L, phosphatase 11 5g/L, surplus is water; Under 75-85 DEG C of condition, Mg alloy castings is soaked to 10min in zinc alloy immersion liquid;

4) electro-coppering: described copper-plated plating solution consists of: CuSO ₄40g/L, CuCl ₂14g/L, K ₂cO ₃55g/L, K ₄p ₂o ₇3H ₂o260g/L, C ₄h ₄o ₆kNa3H ₂o44g/L, K ₂hPO ₄3H ₂o65g/L, the hydroxy ethylene two sour 100g/L that sees, phytic acid 0.5g/L, surplus is water; Electroplating technology is: pH is 8-8.5, and current density is 3-3.5A/dm ², temperature is 35-45 DEG C.

Embodiment bis-

A technique for magnesium alloy shell surface electrical copper facing, described technique comprises the steps:

1) clean: under the condition of 65-75 DEG C, Mg alloy castings is soaked in alkaline wash to 10min, alkali lye consists of sodium hydroxide 76g/L, sodium phosphate 6g/L, surplus is water, then washing; Under the condition of 35-45 DEG C, Mg alloy castings is soaked in tartrate to 60s, then washing;

2) activation: Mg alloy castings is activated in activator to 15min under the condition of room temperature, then washing; Activation solution consists of citric acid 175g/L, NaF200g/L, and surplus is water;

3) soak zinc alloy: zincate solution consists of: ZnSO ₄7H ₂o36g/L, Na ₄p ₂o ₇10H ₂o160g/L, NaF12g/L, KF6g/L, Na ₂cO ₃12g/L, NiSO ₄2g/L, phosphatase 11 8g/L, surplus is water; Under 75-85 DEG C of condition, Mg alloy castings is soaked to 15min in zinc alloy immersion liquid;

4) electro-coppering: described copper-plated plating solution consists of: CuSO ₄50g/L, CuCl ₂12g/L, K ₂cO ₃65g/L, K ₄p ₂o ₇3H ₂o240g/L, C ₄h ₄o ₆kNa3H ₂o48g/L, K ₂hPO ₄3H ₂o55g/L, the hydroxy ethylene two sour 110g/L that sees, phytic acid 0.3g/L, surplus is water; Electroplating technology is: pH is 8-8.5, and current density is 3-3.5A/dm ², temperature is 35-45 DEG C.

Embodiment tri-

A technique for magnesium alloy shell surface electrical copper facing, described technique comprises the steps:

1) clean: under the condition of 65-75 DEG C, Mg alloy castings is soaked in alkaline wash to 9min, alkali lye consists of sodium hydroxide 75g/L, sodium phosphate 7g/L, surplus is water, then washing; Under the condition of 35-45 DEG C, Mg alloy castings is soaked in tartrate to 50s, then washing;

2) activation: Mg alloy castings is activated in activator to 10min under the condition of room temperature, then washing; Activation solution consists of citric acid 170g/L, NaF205g/L, and surplus is water;

3) soak zinc alloy: zincate solution consists of: ZnSO ₄7H ₂o34g/L, Na ₄p ₂o ₇10H ₂o165g/L, NaF11g/L, KF7g/L, Na ₂cO ₃10g/L, NiSO ₄2.5g/L, phosphatase 11 7g/L, surplus is water; Under 75-85 DEG C of condition, Mg alloy castings is soaked to 13min in zinc alloy immersion liquid;

4) electro-coppering: described copper-plated plating solution consists of: CuSO ₄45g/L, CuCl ₂13g/L, K ₂cO ₃60g/L, K ₄p ₂o ₇3H ₂o250g/L, C ₄h ₄o ₆kNa3H ₂o46g/L, K ₂hPO ₄3H ₂o60g/L, the hydroxy ethylene two sour 105g/L that sees, phytic acid 0.4g/L, surplus is water; Electroplating technology is: pH is 8-8.5, and current density is 3-3.5A/dm ², temperature is 35-45 DEG C.

Claims (1)

1. a technique for magnesium alloy shell surface electrical copper facing, is characterized in that, described technique comprises the steps:

1) clean: under the condition of 65-75 DEG C, Mg alloy castings is soaked in alkaline wash to 8-10min, alkali lye consists of sodium hydroxide 74-76g/L, sodium phosphate 6-8g/L, surplus is water, then washing; Under the condition of 35-45 DEG C, Mg alloy castings is soaked in tartrate to 40-60s, then washing;

2) activation: Mg alloy castings is activated in activator to 5-15min under the condition of room temperature, then washing; Activation solution consists of citric acid 165-175g/L, NaF200-210g/L, and surplus is water;

3) soak zinc alloy: zincate solution consists of: ZnSO ₄7H ₂o32-36g/L, Na ₄p ₂o ₇10H ₂o160-170g/L, NaF10-12g/L, KF6-8g/L, Na ₂cO ₃8-12g/L, NiSO ₄2-3g/L, phosphatase 11 5-18g/L, surplus is water; Under 75-85 DEG C of condition, Mg alloy castings is soaked to 10-15min in zinc alloy immersion liquid;

4) electro-coppering: described copper-plated plating solution consists of: CuSO ₄40-50g/L, CuCl ₂12-14g/L, K ₂cO ₃55-65g/L, K ₄p ₂o ₇3H ₂o240-260g/L, C ₄h ₄o ₆kNa3H ₂o44-48g/L, K ₂hPO ₄3H ₂o55-65g/L, the hydroxy ethylene two sour 100-110g/L that sees, phytic acid 0.3-0.5g/L, surplus is water; Electroplating technology is: pH is 8-8.5, and current density is 3-3.5A/dm ², temperature is 35-45 DEG C.