1. According to the process characteristics, there are two types of gold plating: cyanide-free gold plating and cyanide-plated gold plating. Cyanide solution is divided into high cyanide solution and low cyanide solution.
2. According to the concentration of hard gold plating solution, the gold plating solution is generally acidic, and its gold content is low, up to 0.4-0.5g/l. This kind of plating solution has low cost, so the loss brought out by the solution is less. The color of the gold layer obtained by this plating solution is turquoise gold, which is especially suitable for small hardware parts such as buttons and belt buckles that have a large plating batch and low processing cost, and need to be gold-plated.
3. According to the function, the hard gold plating solution has pre-gold plating. The process is to pre-gold in a specific hard gold plating solution before transferring to normal gold plating. There are several benefits of re-gold plating after pre-gold plating:
1) Ensure the bonding force of the gold-plated layer.
2) Reduce the possibility of contamination of the positive gold plating tank.
3) It is economical, practical and cost-effective.
4) Improve the density of the gold plating layer.
4. The hard gold plating solution has pure gold plating according to its service life. It means that the gold plating cannot contain other metal components. Therefore, various metal salts should not be used as additives to achieve a certain function in the gold plating process. However, the pure gold coating is soft, ductile and not wear-resistant. Wear-resistant gold plating is to increase the hardness of the gold layer to meet the functional requirements of certain electronic components and improve wear resistance. In order to obtain a coating layer with good wear resistance, a cobalt salt, nickel salt and other additives are generally added to an acidic hard gold plating solution to deposit a gold alloy coating layer containing certain cobalt or nickel components, so as to improve the wear resistance.