Circuit board gold plating process introduction

- Dec 26, 2019-

Circuit board gold plating process introduction

Compared with the gold plating process, silver plating is more optimistic about gold plating, because gold plating is more durable, silver plating is not as corrosion resistant as gold, and the silver layer will oxidize and slowly turn black when the silver plating time is long, so even the process is better , Lost the glory of the surface, its viewing price will be greatly reduced.

The gold plating process must be very rigorous, especially the gold plating process flow of circuit boards. According to the characteristics of its gold plating, there are two types: cyan-free gold plating and cyan-gold plating. The cyanide bath is divided into high cyanide and low cyanide bath. The cyanide-free plating solution is more commonly used as a sulfite plating solution.

   The silver-plated layer is easy to polish, has strong reflective ability and good thermal conductivity, electrical conductivity, and welding performance. Silver plating was first used for decoration. In the electronics industry, communication configuration, and instrumentation manufacturing industry, silver plating is generally accepted to eliminate the appearance of metal parts, and improve the welding ability of metals.

 Gold plating is divided into electroplated hard gold (gold alloy) and water gold (pure gold) processes. The composition of hard gold plating and soft gold bath fluid is basically the same, except that some trace metals such as nickel or cobalt or iron are added in the hard gold bath;

   Circuit board gold plating process introduction


 ①Purpose and function: As a precious metal, gold has good characteristics such as good solderability, oxidation resistance, corrosion resistance, low contact resistance, good abrasion resistance, etc .;

 ② At present, the electroplating gold of circuit boards is mainly a citrate gold bath, which is widely used for its simple maintenance and simple and convenient operation;

 ③ The content of water, gold and gold is controlled at about 1 g / liter, the pH value is about 4.5, the temperature is 35 degrees, the specific gravity is about 14 Baume degrees, and the current density is about 1 ASD;

 ④ The main additions are acid-adjusted salts and basic-adjusted salts that adjust the PH value, conductive salts that regulate the specific gravity, supplemental additives for gold plating, and gold salts;

 ⑤In order to protect the gold cylinder, a citric acid immersion tank should be added in front of the gold cylinder, which can effectively reduce the pollution to the gold cylinder and keep the gold cylinder stable;

 ⑥ After electroplating the gold plate, a pure water wash should be used as the recovery water wash, and it can also be used to supplement the liquid level of the gold cylinder. After the recovery water wash, the secondary countercurrent pure water wash is used. To prevent the gold plate from oxidizing;

 ⑦The gold cylinder should use platinum-plated titanium mesh as the anode. Generally, stainless steel 316 is easy to dissolve, causing metal such as nickel iron chromium to pollute the gold cylinder, causing defects such as white plating, exposed plating, and blackening; 

 ⑧The organic pollution of gold cylinder should be continuously filtered with carbon core, and supplemented with appropriate amount of gold plating additives.

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