A chemical silvering solution and a silvering method

An electroless silver plating and silver salt technology, applied in the field of electroless plating, can solve the problems of low utilization rate, poor stability, easy oxidation and yellowing of the coating, and achieve the effect of fine coating

Active Publication Date: 2015-02-11
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The slightly alkaline electroless silver plating solution has poor stability and low utilization rate, and the plating layer is easy to oxidize and turn yellow

Method used

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  • A chemical silvering solution and a silvering method
  • A chemical silvering solution and a silvering method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Electroless silver plating solution: silver nitrate 0.5g / L; ammonium citrate 0.5g / L; ammonium sulfate 0.5g / L; cysteine ​​1ppm; sodium lauryl sulfate 3ppm; ceric sulfate 1ppm; lanthanum oxide 5ppm; PEG-1000 10ppm; use sodium hydroxide solution to adjust the pH value to 9.0 to obtain chemical silver plating solution A1;

[0023] Electroless silver plating:

[0024] 1. Degreasing: Ultrasonic degreasing of the copper workpiece to be plated;

[0025] 2. Acid etching: soak the workpiece to be plated obtained in step 1 with dilute acid solution to remove the oxide layer;

[0026] 3. Electroless silver plating: Heat the electroless silver plating solution A1 to 45°C, and then place the workpiece to be plated obtained in step 2 in the heated chemical silver plating solution to react for 9 minutes;

[0027] 4. Protection treatment: place the plated piece obtained in step 3 in a silver protectant for treatment for 3 minutes, and then dry to obtain the silver-plated product S1. ...

Embodiment 2

[0030] Electroless silver plating solution: silver iodide 5g / L; ammonium citrate 0.5g / L; ammonium sulfate 0.5g / L; cysteine ​​1ppm; cerium sulfate 10ppm; sodium lauryl sulfate 3ppm; PEG-1000 7ppm; oxidation Lanthanum 20ppm, with sodium hydroxide solution, adjust the pH value to be 9.8 to obtain electroless silver plating solution A2;

[0031] Electroless silver plating:

[0032] 1. Degreasing: Ultrasonic degreasing of the copper workpiece to be plated;

[0033] 2. Acid etching: soak the workpiece to be plated obtained in step 1 with dilute acid solution to remove the oxide layer;

[0034] 3. Electroless silver plating: Heat the electroless silver plating solution A2 to 41°C, and then place the workpiece to be plated obtained in step 2 in the heated chemical silver plating solution for 9 minutes;

[0035] 4. Protection treatment: place the plated piece obtained in step 3 in a silver protectant for treatment for 3 minutes, and then dry to obtain a silver-plated product S2.

[...

Embodiment 3

[0038] Electroless silver plating solution: silver eicosanoate 0.1g / L; ammonium citrate 0.25g / L; cysteine ​​1ppm; ceric sulfate 5ppm; benzotriazole 0.2ppm; sodium lauryl sulfate 10ppm; PEG-300 40ppm; Lanthanum oxide 20ppm; Use sodium hydroxide solution to adjust the pH value to 8.8 to obtain chemical silver plating solution A4;

[0039] Electroless silver plating:

[0040] 1. Degreasing: Ultrasonic degreasing of the copper workpiece to be plated;

[0041] 2. Acid etching: soak the workpiece to be plated obtained in step 1 with dilute acid solution to remove the oxide layer;

[0042] 3. Electroless silver plating: Heat the electroless silver plating solution A3 to 46°C, and then place the workpiece to be plated obtained in step 2 in the heated chemical silver plating solution for 5 minutes;

[0043] 4. Protection treatment: place the plated piece obtained in step 3 in a silver protectant for treatment for 3 minutes, and then dry to obtain a silver-plated product S3.

[0044]...

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Abstract

A chemical silvering solution is provided. The chemical silvering solution comprises a silver salt, a complexing agent, a pH conditioner, a surfactant and additives. The additives comprise lanthanum oxide and ceric sulfate. The weight ratio of the lanthanum oxide to the ceric sulfate is 2-5:1. The pH of the chemical silvering solution is 8.3-9.8. A chemical silvering method using the chemical silvering solution is also provided by the invention. Products obtained by using the chemical silvering solution are compact and uniform in appearance, while products obtained by using silvering solutions of the same kind in the market have appearances with protruding and nonuniform particles and even have skip plating in local parts. The chemical silvering solution has a longer time for starting decomposition than the silvering solutions of the same kind in the market and is more stable.

Description

technical field [0001] The invention belongs to the field of electroless plating, in particular to an electroless silver plating solution and a silver plating method. Background technique [0002] Since silver has good solderability, weather resistance and electrical conductivity, the use of electroless silver plating to protect copper substrates has been widely used in the printed circuit board industry. At present, there are two methods of copper-based electroless silver plating commonly used: 1. Redox chemical silver plating method; 2. Displacement chemical silver plating method. Due to redox silver plating, an additional reducing agent needs to be added, which makes the electroless silver plating solution easily unstable, and when used, it is necessary to carry out corresponding sensitization pretreatment on the metal substrate, and the production cost is high, which hinders its industrial application. Because of its wide application, displacement electroless silver pla...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C18/44
CPCC23C18/44
Inventor 董有军连俊兰
Owner BYD CO LTD
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