CN1396303A

CN1396303A - Metallic plating liquid

Info

Publication number: CN1396303A
Application number: CN 01124665
Authority: CN
Inventors: 何人杰
Original assignee: FURUN SCIENCE AND TECHNOLOGY DEVELOPMENT CO LTD JIANGMEN CITY
Current assignee: FURUN SCIENCE AND TECHNOLOGY DEVELOPMENT CO LTD JIANGMEN CITY
Priority date: 2001-07-07
Filing date: 2001-07-19
Publication date: 2003-02-12

Abstract

A metal plating liquid by means of redox reaction contains water as solvent, nickel sulfate and/or nickel chloride for providing nickelousions, sodium hypophosphite as reducer, sodium citrate as complexing agent and acrylthiourea as stabilizer. Its advantages are no environmental pollution, low cost and high adhesion and resistances to rust and corrosion of plated layer.

Description

Metal plating solution

The invention relates to a chemical plating solution for metal surface treatment, in particular to a metal nickel plating solution.

Background

The electroplating method commonly used for the surface treatment of the metal at present has the following defects:

in the electroplating production process, the highly toxic cyanide is widely used, belongs to stable inorganic substances, is not easy to decompose under common conditions, and has high treatment difficulty, and the cyanide has high toxicity and can cause serious pollution to the ecological environment; the investment of factory buildings and equipment is large, the requirements of a plating bath and supporting facilities are high, and the plating bath is difficult to be suitable for general investors; the direct current with larger load is used, so that the energy consumption cost is high; the investment is large, the energy consumption is high, and in addition, expensive anode metal is used, so the comprehensive cost is high; the process has many links, long period and difficult quality control.

Disclosure of Invention

The invention aims to provide a metal surface electroplating treatment method which does not contain cyanide and does not pollute the environment, aiming at the defects of the commonly used metal surface electroplating treatment method; the investment is less, the effect is fast and the cost is low; direct current is not needed, and energy is saved; the plating solution has stable structure, convenient operation, strong anti-rust capability of the plated product, corrosion resistance, uniform plating layer, strong binding force and wear resistance.

The present invention achieves the above object by: a metal plating solution using water as solvent contains bivalent Ni ions supplied by Ni sulfate and/or Ni chloride and able to be reduced and deposited on the surface of plated metal, sodium hypophosphite as reducer for reducing bivalent Ni ions, sodium citrate as complexing agent for complexing bivalent Ni ions, and stabilizer for stabilizing plating solution and prolonging its service lifePropenyl thiourea; also comprises a buffering agent sodium acetate for adjusting the PH value range of the metal plating solution and a complexing agent lactic acid for stabilizing and complexing divalent nickel ions in the plating solution; the method also comprises monosodium glutamate for improving the brightness and compactness of the coating, copper sulfate for improving the brightness of the coating and sodium dodecyl sulfate for improving the smoothness and uniformity of the coating, so that the plating solution stably works at 85-95 ℃, and the chemical reaction equation is as follows: 。

because the invention adopts chemical metal plating solution, utilizes redox reaction, takes water as solvent, comprises divalent nickel ions which can be reduced and deposited on the surface of the plated metal and are provided by nickel sulfate or/and nickel chloride, reducing agent sodium hypophosphite which provides electrochemical power for reducing the divalent nickel ions, complexing agent sodium citrate which complexes the divalent nickel ions, and stabilizing agent propenyl thiourea which stabilizes the plating solution and prolongs the service life of the plating solution, thereby overcoming the defects of the commonly used metal surface electroplating treatment method and providing a cyanide-free environment-friendly plating solution; the investment is less, the effect is fast and the cost is low; direct current is not needed, and energy is saved; the plating solution has stable structure, convenient operation, strong anti-rust capability of the plated product, strong binding force of the plating layer and wear resistance.

Detailed Description

The metal plating solution takes water as a solvent, and also comprises divalent nickel ions which can be reduced and deposited on the surface of plated metal and are provided by nickel sulfate or/and nickel chloride, reducing agent sodium hypophosphite which provides electrochemical power for reducing the divalent nickel ions, complexing agent sodium citrate which complexes the divalent nickel ions, and stabilizing agent propenyl thiourea which stabilizes the plating solution and prolongs the service life of the plating solution; also comprises a buffering agent sodium acetate for adjusting the PH value range of the metal plating solution and a complexing agent lactic acid for stabilizing and complexing divalent nickel ions in the plating solution; the metal plating solution also comprises monosodium glutamate for improving the brightness and compactness of the plating layer, copper sulfate for improving the brightness of the plating layer and sodium dodecyl sulfate for improving the smoothness and uniformity of the plating layer. Nickel sulfate or/and nickel chloride provide metallic nickel ions which can be reduced; next timeSodium phosphate provides the electrochemical power for reducing metallic nickel ions, and utilizes the chemical reaction equation: reducing the metallic nickel ions into metallic nickel; sodium citrate provides a complexing agent for complexing metal ions; a buffering agent for stabilizing the pH value range of the plating solution by sodium acetate; the lactic acid stabilizes the complexing agent of the plating solution performance and improves the coating smoothness; the monosodium glutamateimproves the brightness and compactness of the coating; the copper sulfate increases the brightness of the plating layer; the sodium dodecyl sulfate can improve the evenness and the plating uniformity of a plating layer; the propenyl thiourea is stable, the service life of the plating solution is prolonged, and the plating solution can be recycled under normal operation conditions.

The prepared plating solution contains 25-30 g/L of nickel sulfate or/and nickel chloride, 22-28 g/L of sodium hypophosphite, 4-8 g/L of sodium citrate and 0.0006-0.0010 g/L of propenyl thiourea except water; the content of sodium acetate in the prepared plating solution is 8-14 g/L, the content of lactic acid is 14-20 g/L, the content of monosodium glutamate in the prepared plating solution is 1-3 g/L, the content of copper sulfate is 0.002-0.005 g/L, and the content of sodium dodecyl sulfate is 0.00001-0.00003 g/L.

Particularly, the optimal content of each component of the metal plating solution is as follows: 28 g/L of nickel sulfate or/and nickel chloride, 25 g/L of sodium hypophosphite, 6 g/L of sodium citrate, 12 g/L of sodium acetate, 18 g/L of lactic acid, 2 g/L of monosodium glutamate, 0.003 g/L of copper sulfate, 0.00002 g/L of sodium dodecyl sulfate and 0.0008 g/L of propenyl thiourea; adjusting the pH value of the metal plating solution to 4.5-4.8 by using 10% dilute sulfuric acid or 25% ammonia water, wherein the pH value of the metal plating solution is preferably 4.6; particularly, the divalent nickel ions which can be reduced and deposited on the surface of the plated metal are preferably provided by nickel sulfate, and after the divalent nickel ions are prepared into the chemical nickel plating solution according to the optimal proportion, a full-bright metal nickel plating layer can be obtained, and the plating layer has the unique advantages of high density, low porosity, corrosion resistance and the like; in the optimal valueformula of the plating solution, the sum of all components in every 100 g of the plating solution is 8.34 g, and the pure water is 91.66 g.

The invention is described in detail below with reference to specific examples:

example 1:

the preparation method comprises the following steps of taking nickel sulfate, sodium hypophosphite, sodium citrate and propenyl thiourea as formula raw materials, and preparing the raw materials according to the content of nickel sulfate or/and nickel chloride being 25-30 g/L, the content of sodium hypophosphite being 22-28 g/L, the content of sodium citrate being 4-8 g/L and the content of propenyl thiourea being 0.0006-0.0010 g/L; preferably 28 g/L nickel sulfate or/and nickel chloride, 25 g/L sodium hypophosphite, 6 g/L sodium citrate and 12 g/L sodium acetate, and can be prepared into chemical nickel plating solution, so that a uniform nickel plating layer with low pores and better corrosion resistance can be obtained. Example 2: the method comprises the following steps of taking nickel sulfate, sodium hypophosphite, sodium citrate, sodium acetate, lactic acid and propenyl thiourea as formula raw materials, wherein the content of nickel sulfate or/and nickel chloride is 25-30 g/L, the content of sodium hypophosphite is 22-28 g/L, the content of sodium citrate is 4-8 g/L, the content of sodium acetate is 8-14 g/L, the content of lactic acid is 14-20 g/L, and the content of propenyl thiourea is 0.0006-0.0010 g/L; preferably, the nickel sulfate or/and nickel chloride is 28 g/L, the sodium hypophosphite is 25 g/L, the sodium citrate is 6 g/L, the sodium acetate is 12 g/L, the lactic acid is 18 g/L, and the propenyl thiourea is 0.0008 g/L, and the chemical nickel plating solution prepared by the method can obtain a uniform, compact, low-porosity, firm binding force, non-shedding, non-foaming, strong anti-rust capability and wear-resistant semi-bright nickel plating layer.

Example 3: the method is characterized by taking nickel sulfate, sodium hypophosphite, sodium citrate, sodium acetate, lactic acid, monosodium glutamate, copper sulfate, sodium dodecyl sulfate and propenyl thiourea as formula raw materials, wherein the content of nickel sulfate or/and nickel chloride is 25-30 g/L, the content of sodium hypophosphite is 22-28 g/L, the content of sodium citrate is 4-8 g/L, the content of propenyl thiourea is 0.0006-0.0010 g/L, the content of sodium acetate is 8-14 g/L, the content of lactic acid is 14-20 g/L, the content of monosodium glutamate is 1-3 g/L, the content of copper sulfate is 0.002-0.005 g/L, and the content of sodium dodecyl sulfate is 0.00001-0.00003 g/L; preferably 28 g/L of nickel sulfate or/and nickel chloride, 25 g/L of sodium hypophosphite, 6 g/L of sodium citrate, 12 g/L of sodium acetate, 18 g/L of lactic acid, 2 g/L of monosodium glutamate, 0.003 g/L of copper sulfate, 0.00002 g/L of sodium dodecyl sulfate and 0.0008 g/L of propenyl thiourea are mixed according to the proportion to prepare the chemical nickel plating solution; the best full-bright nickel coating with the advantages of uniformity, compactness, firm binding force, no shedding, no bubbling, wear resistance and corrosion resistance can be obtained.

The preparation method comprises the following steps:

preparing 9 materials of nickel sulfate, sodium hypophosphite, sodium citrate, sodium acetate, lactic acid, monosodium glutamate, copper sulfate, sodium dodecyl sulfate and propenyl thiourea into three components:

group A: nickel sulfate;

group B: sodium phosphite;

group C: sodium citrate, sodium acetate, lactic acid, monosodium glutamate, copper sulfate, sodium dodecyl sulfate and propenyl thiourea.

① dissolving A, B, C three components in deionized water to obtain a liquid, ② slowly pouring the liquid in the group B into the liquid in the group A, pouring while stirring uniformly until the liquid in the group A, B is fully and uniformly mixed, ③ slowly pouring the liquid in the group C into the mixed liquid in the group A, B while stirring continuously until the liquid is fully and uniformly mixed, ④ diluting with deionized water to a required concentration, ⑤ adjusting the pH value, and adjusting the pH value to 4.5-4.8 with 10% dilute sulfuric acid or 25% ammonia water.

After the plating solution is prepared, other necessary process conditions during production are as follows: 1. plating a piece: the pretreatment of oil removal and rust removal is required; 2. plating bath: should be made of polypropylene or polytetrafluoroethylene, and can not adopt plastic plates or other materials containing other fillers; 3. plating solution: it is heated to this temperature. 85-92 ℃, and the optimal temperature is 88 ℃; 4. pH: adjusting the value to 4.5-4.8; 5. plating time: the time is longer, the thicker the plating layer is, and generally the time is not more than 3 hours, and the plating solution is required to be operated in a circulating filtration state.

The invention can make the metal surface even, firm, non-shedding, non-bubbling, strong anti-rust ability, and wear resistant.

Claims

1. The metal plating solution uses water as solvent, and is characterized by that said metal plating solution also includes bivalent nickel ions which can be reduced and deposited on the metal surface to be plated and are provided by nickel sulfate or/and nickel chloride, reducing agent sodium hypophosphite capable of providing electrochemical power for reducing bivalent nickel ions, complexing agent sodium citrate for complexing bivalent nickel ions and stabilizing agent propenyl thiourea for stabilizing plating solution and prolonging service life of plating solution.

2. The metal plating solution of claim 1, further comprising a buffering agent sodium acetate for adjusting the pH value range of the metal plating solution, and a complexing agent lactic acid for stabilizing and complexing divalent nickel ions in the plating solution.

3. The metal plating solution of claim 2, further comprising monosodium glutamate for increasing the brightness and compactness of the plating layer, copper sulfate for increasing the brightness of the plating layer, and sodium dodecyl sulfate for improving the flatness and uniformity of the plating layer.

4. The metal plating solution of claim 1, wherein the plating solution is prepared to contain nickel sulfate or/and nickel chloride in an amount of 25 to 30 g/l, sodium hypophosphite in an amount of 22 to 28 g/l, sodium citrate in an amount of 4 to 8 g/l, and thiopropenyl urea in an amount of 0.0006 to 0.0010 g/l.

5. The metal plating solution according to claim 2, wherein the plating solution is prepared such that the content of sodium acetate is 8 to 14 g/l and the content of lactic acid is 14 to 20 g/l.

6. The metal plating solution of claim 3, wherein the prepared plating solution contains 1 to 3 g/L of monosodium glutamate, 0.002 to 0.005 g/L of copper sulfate, and 0.00001 to 0.00003 g/L of sodium dodecyl sulfate.

7. The metal plating solution according to claims 4, 5 and 6, characterized in that the optimum contentsof the components of the metal plating solution are: 28 g/L of nickel sulfate or/and nickel chloride, 25 g/L of sodium hypophosphite, 6 g/L of sodium citrate, 12 g/L of sodium acetate, 18 g/L of lactic acid, 2 g/L of monosodium glutamate, 0.003 g/L of copper sulfate, 0.00002 g/L of sodium dodecyl sulfate and 0.0008 g/L of propenyl thiourea.

8. The metal plating solution according to claim 1, wherein the pH of the metal plating solution is adjusted to 4.5 to 4.8 by using 10% dilute sulfuric acid or 25% ammonia water.

9. The metal plating solution of claim 1 wherein the metal plating solution has a PH of preferably 4.6.

10. A metal plating bath according to claim 1, characterised in that the divalent nickel ions which can be reduced and deposited on the surface to be plated are preferably provided by nickel sulphate.