CN103898583A

CN103898583A - Chemical nickel-plating solution electroplating chromium on surface of magnesium alloy die casting

Info

Publication number: CN103898583A
Application number: CN201310219480.6A
Authority: CN
Inventors: 钱永清
Original assignee: WUXI XISHAN DISTRICT EHU TOWN DANGKOU QINGDANG METAL PRODUCT FACTORY
Current assignee: WUXI XISHAN DISTRICT EHU TOWN DANGKOU QINGDANG METAL PRODUCT FACTORY
Priority date: 2013-06-03
Filing date: 2013-06-03
Publication date: 2014-07-02

Abstract

The invention discloses a chemical nickel-plating solution electroplating chromium on the surface of a magnesium alloy die casting. The chemical nickel-plating solution comprises the following components: 40-50g/L of nickel sulfate, 62-68g/L of sodium hypophosphite, 35-41g/L of trisodium citrate, 32-38g/L of lactic acid, 36-42g/L of acetic acid, 2.0-6.0g/L of sodium fluoride, 6.0-9.0g/L of NH4HF2, 3-7mg/L of thiourea and the balance of water.

Description

A kind of chemical nickel-plating solution of magnesium alloy die casting electroplating Cr onto surface

Technical field

The present invention relates to electroplating technology field, relate in particular to a kind of chemical nickel-plating solution of magnesium alloy die casting electroplating Cr onto surface.

Background technology

Magnesium alloy is described as the green metal structured material of 21 century, has that density is low, a specific tenacity and specific rigidity is high and damping and amortization, machinability, castability are superior, in automotive industry, space flight and aviation industry, electronic industry, has obtained increasingly extensive application.Magnesium raw material is abundant, and in natural resources, in the 8th, but as structured material, its solidity to corrosion is poor has restricted the major cause that it uses widely.

The Standard Electrode Potentials of magnesium is-2.34V, there is very high reactive behavior, in air or solution, magnesium alloy can generate one deck passive film as thin as a wafer very soon, thereby while causing plating or electroless plating, metal plating and magnesium substrate adhesion are not strong, do not reach service requirements, in addition according to known to the observation of magnesium alloy materials metal structure, magnesium alloy is to form α phase by purity compared with high magnesium, and the β being formed by alloy ingredient forms mutually, wherein β order skewness and electromotive force are higher than α phase, therefore Mg alloy surface Potential Distributing inequality, galvanic corrosion easily occurs in treatment solution makes Mg alloy surface plating or electroless plating become difficulty, therefore wish obtains the metal plating with good combination power, before plating and electroless plating, must first carry out special pre-treatment to remove surperficial passive film and segregation layer to magnesium alloy materials, to obtain one evenly, clean surface.

Surface pretreatment common method based on magnesium alloy plating or electroless plating has at present: Dow ^[1]the zinc method of the soaking technique of company exploitation, main flow process is: oil removing → anode cleaning → acid etching → acid activation → soak zinc → cyanide electroplating.On this basis, constantly improve, as Olsen ^[2]the Norsk-Hydro technique proposing: oil removing → acid etching → alkaline purification → soak zinc → cyanide electroplating, Dennis ^[3]wCM technique is proposed: oil removing → acid etching → acid activation → soak zinc → cyanide electroplating.In these pre-treating technology plating solutions, contain hypertoxic prussiate, the liquid waste disposal expense of generation is high.

Under the pressure of increasingly serious resources and environment protection; carrying out the researchs of magnesium metallic substance and anti-corrosion method thereof is one of urgent task of world's Sustainable development; although obtaining interim progress aspect magnesium alloy protection in recent years; and be applied in certain field, but still there is no to form the method that can replace traditional magnesium alloy plating completely.Therefore the electroplating technology that, hope can be developed a kind of environmental protection meets the production requirement of modern clean energy-saving.

Magnesium alloy die casting has been widely used in the fields such as automobile, traffic, aerospace, and wherein the application of some die casting needs surface that electrolytic coating is set, but the report about the electroplating technology of magnesium alloy die casting in prior art is little.

And conventionally need to carry out chemical nickel plating operation before electrodeposited chromium, and be beneficial to follow-up chrome-plated process, therefore, the effect of chemical nickel plating will directly affect the coating performance of electrodeposited chromium.

Summary of the invention

The object of the invention is to propose a kind of chemical nickel-plating solution of magnesium alloy die casting electroplating Cr onto surface, by the adjustment to bath composition, obtain good chemical Ni-plating layer, for follow-up chrome-plated process is laid a good foundation.

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

A chemical nickel-plating solution for magnesium alloy die casting electroplating Cr onto surface, the plating solution of described chemical nickel plating consists of: single nickel salt 40-50g/L, inferior sodium phosphate 62-68g/L, trisodium citrate 35-41g/L, lactic acid 32-38g/L, acetic acid 36-42g/L, Sodium Fluoride 2.0-6.0g/L, NH ₄hF ₂6.0-9.0g/L, thiocarbamide 3-7mg/L, surplus is water.

Preferably, the plating solution of described chemical nickel plating consists of: single nickel salt 45g/L, inferior sodium phosphate 65g/L, trisodium citrate 38g/L, lactic acid 35g/L, acetic acid 39g/L, Sodium Fluoride 4.0g/L, NH ₄hF ₂7.5g/L, thiocarbamide 5mg/L, surplus is water.

The present invention has advantages of:

By the adjustment to chemical nickel-plating plating solution component, do not adopt poisonous, pollute high component, make plating technic Environmental Safety, and lay a good foundation for subsequent technique, make the chromium coating bonding force of final preparation strong.

Embodiment

Embodiment mono-

A chemical nickel-plating solution for magnesium alloy die casting electroplating Cr onto surface, the plating solution of described chemical nickel plating consists of: single nickel salt 40g/L, inferior sodium phosphate 68g/L, trisodium citrate 35g/L, lactic acid 38g/L, acetic acid 36g/L, Sodium Fluoride 6.0g/L, NH ₄hF ₂6.0g/L, thiocarbamide 7mg/L, surplus is water; Processing condition are: pH value 4.5-5.5; Temperature 60-70 ℃, time 2.0h.

Embodiment bis-

A chemical nickel-plating solution for magnesium alloy die casting electroplating Cr onto surface, the plating solution of described chemical nickel plating consists of: single nickel salt 50g/L, inferior sodium phosphate 62g/L, trisodium citrate 41g/L, lactic acid 32g/L, acetic acid 42g/L, Sodium Fluoride 2.0g/L, NH ₄hF ₂9.0g/L, thiocarbamide 3mg/L, surplus is water; Processing condition are: pH value 4.5-5.5; Temperature 60-70 ℃, time 4.0h.

Embodiment tri-

A chemical nickel-plating solution for magnesium alloy die casting electroplating Cr onto surface, the plating solution of described chemical nickel plating consists of: single nickel salt 45g/L, inferior sodium phosphate 65g/L, trisodium citrate 38g/L, lactic acid 35g/L, acetic acid 39g/L, Sodium Fluoride 4.0g/L, NH ₄hF ₂7.5g/L, thiocarbamide 5mg/L, surplus is water.

Claims

1. a chemical nickel-plating solution for magnesium alloy die casting electroplating Cr onto surface, is characterized in that, the plating solution of described chemical nickel plating consists of: single nickel salt 40-50g/L, inferior sodium phosphate 62-68g/L, trisodium citrate 35-41g/L, lactic acid 32-38g/L, acetic acid 36-42g/L, Sodium Fluoride 2.0-6.0g/L, NH ₄hF ₂6.0-9.0g/L, thiocarbamide 3-7mg/L, surplus is water.

2. the chemical nickel-plating solution of a kind of magnesium alloy die casting electroplating Cr onto surface as claimed in claim 1, is characterized in that, the plating solution of described chemical nickel plating consists of: single nickel salt 45g/L, inferior sodium phosphate 65g/L, trisodium citrate 38g/L, lactic acid 35g/L, acetic acid 39g/L, Sodium Fluoride 4.0g/L, NH ₄hF ₂7.5g/L, thiocarbamide 5mg/L, surplus is water.