CN-121992383-A - High-stability alkaline chemical nickel-phosphorus-copper ternary alloy plating solution and plating method

Abstract

The invention discloses a high-stability alkaline chemical nickel-phosphorus-copper ternary alloy plating solution and a plating method, and belongs to the technical field of metal surface treatment. According to the method, the sodium citrate, the sodium pyrophosphate and the sodium lactate are compounded to serve as complexing agents, urea and thiourea or lead nitrate are combined to serve as stabilizing agents, so that the preferential replacement reaction of Cu 2+ is effectively inhibited, and the uniform co-deposition of the Ni-P-Cu ternary alloy is realized. The plating solution has high stability under the conditions of pH 9.0-10.0 and temperature 63-68 ℃, can prepare a thick plating layer with copper content more than 5 percent which is more than or equal to 50 mu m, is suitable for various base materials such as magnesium alloy, carbon steel, stainless steel and the like, and has the advantages of low energy consumption, wide application range, excellent plating performance and the like.

Inventors

• ZHAO LIN
• WU LIPING
• MU XIN

Assignees

• 中国科学院金属研究所

Dates

Publication Date

20260508

Application Date

20251106

Claims (8)

1. 1. The high-stability alkaline chemical nickel-phosphorus-copper ternary alloy plating solution is characterized by comprising the following components in percentage by weight: 8-12 g/L of nickel sulfate; Copper sulfate 0.5-1.5 g/L; 8-12 g/L of sodium hypophosphite; 4-8 g/L of sodium acetate; Sodium citrate 8-15 g/L; 15-25 g/L of sodium pyrophosphate; 5-8 mL/L of sodium lactate; Urea 0.5-1.5 mg/L; thiourea or lead nitrate 1-2 mg/L; 1-2 mg/L of sodium dodecyl benzene sulfonate.
2. 2. The high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution according to claim 1, wherein the pH value of the high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution is 9.0-10.0, and the temperature is 63-68 ℃.
3. 3. A plating method of the high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution according to any one of claims 1 and 2 is characterized by comprising the following steps of: a) Dissolving nickel sulfate, sodium acetate and sodium citrate in water, and filtering to obtain a solution a; b) Adding copper sulfate and sodium pyrophosphate into the solution a, and stirring for dissolution; c) Adding sodium lactate, urea, thiourea or lead nitrate and surfactant, and fixing the volume to 500 mL; d) Dissolving sodium hypophosphite in water and heating to 65 ℃ to obtain a solution b; e) Mixing the solution a and the solution b, and regulating the pH value to 9.0-10.0 by ammonia water; f) Immersing the workpiece to be plated into the plating solution for chemical plating.
4. 4. The method of plating a high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution according to claim 3, wherein the substrate is subjected to pretreatment including sand blasting, degreasing, activation and nickel preplating prior to plating.
5. 5. The method for plating a high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution according to claim 4, wherein the nickel pre-plating solution comprises nickel chloride 240 g/L, hydrochloric acid 200 g/L, current density 5-8A/dm 2 and time 3-5 min.
6. 6. The plating method of the high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution, according to claim 3, is characterized in that the plating solution is subjected to initial activation treatment through magnesium alloy wires, and the contact time is 3-5 seconds.
7. 7. The method for plating the high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution according to claim 3, wherein the plating deposition rate is 5-8 μm/h.
8. 8. The method for plating the high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution according to claim 3, wherein the plating layer is a Ni-P-Cu ternary alloy and the copper content is not less than 5%.

Description

High-stability alkaline chemical nickel-phosphorus-copper ternary alloy plating solution and plating method Technical Field The invention relates to the technical field of metal surface treatment, in particular to a high-stability alkaline chemical nickel-plating phosphorus-copper ternary alloy plating solution and a plating method. Background Electroless nickel and phosphorus plating technology has been widely used in industry. The traditional chemical nickel-phosphorus plating is mostly carried out under the acidic condition, and a plating layer with high hardness and good corrosion resistance can be obtained, but the plating temperature is high (generally higher than 85 ℃), the energy consumption is high, and the chemical nickel-phosphorus plating is not suitable for non-ferrous metal or plastic non-metal base materials such as aluminum, zinc, magnesium and the like which are sensitive to acid, and the non-ferrous metal or plastic base materials can react with an acidic plating solution. Alkaline electroless nickel-phosphorus plating techniques have been developed which can be carried out at relatively high pH values (typically 8-10) and relatively low temperatures (typically 60-80 ℃), expanding the range of applicability to substrates. However, the existing alkaline chemical nickel plating technology still has two major pain points, namely 1, the stability of the plating solution is poor, the reduction potential of nickel ions is more negative under alkaline conditions, the reaction kinetics is more difficult to control, and the plating solution is extremely easy to generate self-decomposition, so that the service life is short. 2. The complexing agent has poor stability under alkaline conditions, namely, the concentration of the main salt and the reducing agent is limited by the stability of the complexing agent, and the main salt and the reducing agent with higher concentration cannot be adopted, so that the thickness of the deposited electroless plating layer is about 10-20 mu m, and thicker electroless plating layer cannot be prepared. 3. The plating performance is single, the plating is mostly nickel-phosphorus binary alloy, and the function is limited. Although attempts have been made to prepare a composite coating by adding copper salts to alkaline plating solutions, the reduction potential (+0.34V) of copper ions (Cu 2+) is far higher than that of nickel ions (Ni 2+, -0.25V), and the prior displacement reaction is extremely easy to occur, so that loose copper nodules with poor binding force are formed on the surface of a substrate or the coating, or the plating solution is instantaneously decomposed, and a uniform and compact ternary alloy coating cannot be formed. Therefore, developing an alkaline electroless plating solution which can realize nickel, phosphorus and copper ternary codeposition and has high stability is a technical problem to be solved in the field. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a high-stability alkaline chemical nickel-phosphorus-copper ternary alloy plating solution and a plating method. The plating solution successfully inhibits the preferential replacement and precipitation of Cu 2+ through a unique complexing agent compound system, realizes the uniform co-deposition of Ni-P-Cu ternary alloy, and has remarkable plating solution stability. The thicker Ni-P-Cu ternary alloy coating is prepared by optimizing and adding the proportion of the main salt, the reducing agent and the complexing agent. In order to achieve the above object, the present invention provides the following technical solutions: a high-stability alkaline electroless nickel-phosphorus-copper ternary alloy plating solution and a plating method, the technological process comprises: 1) Preparing an alkaline electroless nickel-phosphorus-copper plating solution according to the following formula: the main salt is nickel sulfate NiSO 4 .6H2 O8-12 g/L, copper sulfate NiSO 4 .6H2 O0.5-1.5 g/L Reducing agent NaH 2PO2 . H2 O8-12 g/L; Buffer agent is sodium acetate NaAC, 3H 2 O4-8 g/L; Complexing agent 1, namely sodium citrate 8-15 g/L, complexing agent 2, namely sodium pyrophosphate 15-25 g/L, and complexing agent 3, namely sodium lactate 5-8 ml/L; 0.5-1.5mg/L of urea as stabilizer 1 and 1-2mg/L of PbNO 3 or thiourea as stabilizer 2; 1-2mg/L of sodium dodecyl benzene sulfonate as a surfactant. 2) In the high-stability alkaline electroless nickel-phosphorus-copper plating solution, the addition of high-concentration copper through a complexing agent and a stabilizing agent can not cause the decomposition of the plating solution. Complexing agent 1, namely sodium citrate 8-15 g/L, complexing agent 2, namely sodium pyrophosphate 35-45 g/L, and complexing agent 3, namely sodium lactate 5-8 ml/L; 0.5-1.5mg/L of urea as stabilizer 1 and 1-2mg/L of PbNO 3 or thiourea as stabilizer 2; Wherein the addition amount of the stabilizer 1 corresponds to the addition am