The gold-plated circuit board is divided into electroplated hard gold (gold alloy) and water gold (pure gold) process. The composition of hard gold and soft gold bath is basically the same, but there are some trace elements of metal nickel or cobalt or iron in the hard gold tank.
1. Purpose and effect of gold-plated circuit board: Gold as a precious metal has good weldability, oxidation resistance, corrosion resistance, small contact resistance, good wear resistance of the alloy and so on.
2. At present, the gold plated circuit board is mainly a citrate gold bath, which is widely used for its simple maintenance and simple and convenient operation.
3. The water gold content is controlled at about 1 gram/liter, the pH value is about 4.5, the temperature is 35 degrees, the specific gravity is about 14 waves, and the current density is about 1 ASD.
4. The main added drugs are acid-adjusted salt and basic-adjusted salt which adjust the pH value, conductive salt and gold-plated supplement additive and gold salt which adjust the specific gravity.
5. In order to protect the gold cylinder, a citric acid dip tank should be added before the gold cylinder, which can effectively reduce the pollution of the gold cylinder and maintain the stability of the gold cylinder.
6. After the gold plate is electroplated, a pure water wash is used as the recovery water wash, and it can also be used to supplement the liquid level of the gold cylinder evaporation change. After recovery and washing, it is washed with two-stage counter current pure water. After the gold plate is washed, 10 g/L of alkali solution is placed to prevent oxidation of the gold plate.
7. The gold cylinder should be made of platinized titanium mesh as the anode. Generally, the stainless steel 316 is easily dissolved, causing metal such as nickel-iron-chromium to contaminate the gold cylinder and causing defects such as white gold plating, exposed plating and blackening.
8. The organic pollution of the gold cylinder is continuously filtered by a carbon core, and an appropriate amount of gold plating additive is added.
