阅读说明：本技术 一种电气件低电阻防银变色生产工艺 (Low-resistance silver discoloration prevention production process for electric parts ) 是由 郭玉峰 王立生 唐亮 于 2020-09-15 设计创作，主要内容包括：本发明公开了一种电气件低电阻防银变色生产工艺,该工艺包括如下步骤：镀银初步配料,镀银配料溶液由K-2Cr-2O-7、Be(OH)-2、KNO-3、润湿剂和余量的银组成,各组份质量浓度比为：K-2Cr-2O-(7 )5-10g/L；Be(OH)-2 2-8 g/L；KNO-(3 )10-15 g/L；润湿剂0.2-0.4 g/L；银余量,各组份之和为100%；镀银处理,第一次水洗处理,采用纯水洗；防变色处理,第二次水洗处理热纯水烫干；通过镀银-水洗-纯水洗-防变色处理-水洗-纯水洗-热纯水烫干工艺,镀银层抗变色能力大幅度提高,接触电阻接近于纯银镀层,不含有机溶剂。(The invention discloses a low-resistance silver discoloration prevention production process of an electric part, which comprises the following steps: silver plating primary batching, silver plating batching solution is prepared from K 2 Cr 2 O 7 、Be(OH) 2 、KNO 3 The silver-containing silver paste consists of a wetting agent and the balance of silver, and the mass concentration ratio of each component is as follows: k 2 Cr 2 O 7 5‑10g/L；Be(OH) 2 2‑8 g/L；KNO 3 10-15 g/L; 0.2-0.4 g/L of wetting agent; the balance of silver, the sum of all the components is 100 percent; silver plating treatment, namely, first washing treatment, namely pure water washing; anti-discoloration treatment, namely carrying out secondary washing treatment on hot pure water to be dried; through silver plating, water washing, pure water washing, anti-tarnishing treatment, water washing, pure water washing and hot pure water washingThe silver coating has greatly raised color fastness, contact resistance similar to that of pure silver coating and no organic solvent.)

1. The low-resistance silver discoloration prevention production process of the electric part is characterized in that: the process comprises the following steps:

the method comprises the following steps: silver plating primary batching, silver plating batching solution is prepared from K₂Cr₂O₇、Be(OH)₂、KNO₃The silver-containing silver paste consists of a wetting agent and the balance of silver, and the mass concentration ratio of each component is as follows:

K₂Cr₂O₇ 5-10g/L；

Be(OH)₂ 2-8 g/L；

KNO₃ 10-15 g/L；

0.2-0.4 g/L of wetting agent;

the balance of silver, the sum of all the components is 100 percent;

step two: silver plating, namely, degreasing and derusting the electric piece, immersing the electric piece into a solution prepared from mercuric chloride and the like, and carrying out mercurization treatment to plate a mercury film on the surface of the electric piece; then using the electric element as cathode, the current density of cathode is 0.1-0.3A/dm² Pure silver is used as an anode and is immersed into electrolyte for electroplating, and a silver coating is immersed on the electric part;

step three: the first water washing treatment adopts pure water washing;

step four: performing anti-discoloration treatment, namely chemically passivating by adopting benzotriazole and potassium iodide, wherein the benzotriazole is 0.1-0.15g/L, the temperature is 90-100 ℃, the time is 0.5-1 min, or performing electrolytic passivation by adopting potassium chromate and potassium carbonate, wherein the potassium chromate is 0.2-0.45g/L, and the cathode is passivated by chromic acid;

step five: and carrying out secondary water washing treatment, wherein the pure water current density is as follows: 0.3-0.5A/dm2, water time: 3 min-5 min, the temperature is 60 ℃ -65 ℃, and the solvent pollution among the working procedures is prevented;

step six: drying with hot pure water; the electric part out of the bath is provided with plating solution and dried after being dried by hot water, and the drying temperature is 100-120 ℃.

2. The electrical component low-resistance silver discoloration prevention production process according to claim 1, wherein: the silver plating batching solution is prepared from 8g/L K₂Cr₂O₇、6 g/L Be(OH)₂、12 g/L KNO₃ 0.3g/L wetting agent.

3. The electrical component low-resistance silver discoloration prevention production process according to claim 1, wherein: the pH value of the prepared silver plating solution is 4-5.5, the temperature of the solution is 10-15 ℃, and the preparation time range is 5-10 minutes.

Technical Field

The invention relates to the technical field of silver plating, in particular to a silver plating treatment process for an electrical part.

Background

In the manufacturing process of conductive parts of a high-voltage switch, aluminum alloy is often used as a main material, and the current switching capacity of the switch is ensured by a method of plating silver on the current switching part of a conductor. The silver plating process is very important, the silver plating piece is exposed in the air, the chemical passivation and electrolytic passivation process is adopted, the silver discoloration prevention effect is poor, in addition, a layer of rare and precious metal is electroplated, the good discoloration prevention effect can be achieved, the cost is high, after the silver plating piece is coated with the organic silver discoloration prevention agent, the resistance of the part is increased, and the high-voltage switch cannot be used. Organic solvent is coated, so that the operation is complex, the potential safety hazard is high, and the method is not suitable for automatic production.

Disclosure of Invention

The invention aims to solve the problem of providing a silver-plated layer low-resistance silver discoloration prevention production process which has the advantages that the silver-plated layer discoloration resistance is greatly improved, the contact resistance is close to that of a pure silver plating layer, no organic solvent is contained, and the process is suitable for automatic mass production of electric parts.

In order to achieve the aim, the invention provides a low-resistance silver discoloration prevention production process of an electrical part, which is characterized by comprising the following steps of: the process comprises the following steps:

the method comprises the following steps: silver plating primary batching, silver plating batching solution is prepared from K₂Cr₂O₇、Be(OH)₂、KNO₃The silver-containing silver paste consists of a wetting agent and the balance of silver, and the mass concentration ratio of each component is as follows:

step two: silver plating, namely, degreasing and derusting the electric piece, immersing the electric piece into a solution prepared from mercuric chloride and the like, and carrying out mercurization treatment to plate a mercury film on the surface of the electric piece; then using the electric element as cathode, the current density of cathode is 0.1-0.3A/dm²Pure silver is used as an anode and is immersed into electrolyte for electroplating, and a silver coating is immersed on the electric part;

step three: the first water washing treatment adopts pure water washing;

step four: performing anti-discoloration treatment, namely chemically passivating by adopting benzotriazole and potassium iodide, wherein the benzotriazole is 0.1-0.15g/L, the temperature is 90-100 ℃, the time is 0.5-1 min, or performing electrolytic passivation by adopting potassium chromate and potassium carbonate, wherein the potassium chromate is 0.2-0.45g/L, and the cathode is passivated by chromic acid;

step five: carrying out second water washing treatment; pure water current density: 0.3-0.5A/dm2, water time: 3 min-5 min at 60 +/-5 ℃ to prevent solvent pollution among the working procedures;

step six: drying with hot pure water; the electric part out of the bath is provided with plating solution and dried after being dried by hot water, and the drying temperature is 100-120 ℃.

Preferably, the silver plating batch solution is 8g/L K₂Cr₂O₇)、6g/L Be(OH)₂、12g/L KNO₃0.3g/L wetting agent.

Preferably, the pH value of the prepared silver plating solution is 4-5.5, the temperature of the solution is 10-15 ℃, and the preparation time range is 5-10 minutes.

Compared with the prior art, the invention has the following advantages:

according to the silver plating, water washing, pure water washing, anti-tarnishing treatment, water washing, pure water washing and hot pure water drying technology, the tarnishing resistance of the silver plating layer is greatly improved, the contact resistance is close to that of a pure silver plating layer, no organic solvent is contained, and the anti-tarnishing experiment is based on the following steps: discoloration corrosion resistance test method and hydrogen sulfide test method for metal coating and chemical treatment layer of QB/T3831-1999 light industry product

Contact resistance comparison test: silver plating is carried out on a red copper sheet with the thickness of 0.2mm and the thickness of 25 multiplied by 100mm by adopting a direct current voltage drop method for 10 microns, and then anti-discoloration treatment is carried out according to different processes. The two sheets are superposed and placed in a steel clamp, the clamp is screwed by a bolt, the bolt torque is 20 N.m, the anti-tarnishing capacity of the silver plating process is improved, the waste water is less through reasonable process recycling, and the environmental pollution is reduced; in addition, the service life of the silver coating on the outer surface of the electric component is longer, the discoloration resistant time (min) is long, and the contact resistance m omega (current 10A) is not discolored.

Table 1 shows the silver discoloration experimental data of the present application:

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The following examples, which are given by way of illustration, are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

The first embodiment is as follows: the low-resistance silver discoloration prevention production process for the electric part comprises the following steps:

silver plating primary batching, silver plating batching solution is prepared from K₂Cr₂O₇、Be(OH)₂、KNO₃The silver-containing silver paste consists of a wetting agent and the balance of silver, and the mass concentration ratio of each component is as follows:

K₂Cr₂O₇ 5g/L；Be(OH)₂2g/L；KNO₃10 g/L; 0.2g/L of wetting agent; the balance of silver; silver plating, namely, degreasing and derusting the electric piece, immersing the electric piece into a solution prepared from mercuric chloride and the like, and carrying out mercurization treatment to plate a mercury film on the surface of the electric piece; then using the electric element as cathode, the current density of cathode is 0.1-0.3A/dm²Pure silver is used as an anode and is immersed into electrolyte for electroplating, and a silver coating is immersed on the electric part;

the first water washing treatment adopts pure water washing; performing anti-discoloration treatment, namely chemically passivating by adopting benzotriazole and potassium iodide, wherein the benzotriazole is 0.1-0.15g/L, the temperature is 90 ℃, the time is 0.5 min, or electrolytically passivating by adopting potassium chromate and potassium carbonate, wherein the potassium chromate is 0.2-0.45g/L, and the cathode is passivated by chromic acid;

carrying out second water washing treatment; pure water current density: 0.3A/dm2, water time: 3min at 60 ℃, and preventing solvent pollution among the working procedures;

step six: drying with hot pure water; the electric part out of the bath is provided with plating solution and dried after being dried by scalding in water, and the drying temperature is 100 ℃. The pH value of the prepared silver plating solution is 4, the temperature of the solution is 10 ℃, and the preparation time range is 5 minutes.

The silver plating batching solution is prepared from 8g/L K₂Cr₂O₇)、6g/L Be(OH)₂、12g/L KNO₃0.3g/L wetting agent.

Example two: a low-resistance silver discoloration prevention production process of an electric part comprises the following steps:

silver plating primary batching, silver plating batching solution is prepared from K₂Cr₂O₇、Be(OH)₂、KNO₃The silver-containing silver paste consists of a wetting agent and the balance of silver, and the mass concentration ratio of each component is as follows: k₂Cr₂O₇10g/L；Be(OH)₂8g/L；KNO₃15 g/L; 0.4g/L of wetting agent; silver balance

Silver plating, namely, degreasing and derusting the electric piece, immersing the electric piece into a solution prepared from mercuric chloride and the like, and carrying out mercurization treatment to plate a mercury film on the surface of the electric piece; then using the electric element as cathode, the current density of cathode is 0.1-0.3A/dm²Pure silver is used as an anode and is immersed into electrolyte for electroplating, and a silver coating is immersed on the electric part;

the first water washing treatment adopts pure water washing; performing anti-discoloration treatment, namely performing chemical passivation by adopting benzotriazole and potassium iodide, wherein the benzotriazole is 0.15g/L, the temperature is 100 ℃, the time is 1 minute, or performing electrolytic passivation by adopting potassium chromate and potassium carbonate, wherein the potassium chromate is 0.45g/L, and the cathode is passivated by chromic acid; carrying out second water washing treatment; pure water current density: 0.5A/dm2, water time: 5min, the temperature is 605 ℃, and the solvent pollution among the working procedures is prevented; drying with hot pure water; the electric part out of the bath is provided with plating solution and dried after being dried by scalding in water, and the drying temperature is 120 ℃. The pH value of the prepared silver plating solution is 5.5, the temperature of the solution is 15 ℃, and the preparation time range is 10 minutes.

Example three:

otherwise, as in the first example, the silver plating batch solution is prepared from 8g/L K₂Cr₂O₇)、6g/L Be(OH)₂、12g/L KNO₃0.3g/L wetting agent.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.