The process steps of PCB immersion gold and chemical gold plating are as follows:
1. Pre-treatment: Pre-treatment for immersion gold generally includes four steps: oil removal, micro-etching, activation, and post-immersion. The purpose is to remove oxides from the copper surface and deposit palladium on the copper surface as a nickel immersion activation center. If a certain link is not handled well, it will affect the subsequent nickel and gold sinking, and lead to batch scrapping.
2. Nickel immersion: The immersion gold process is a gold immersion process. The main components in the immersion gold tank include: Au (1.5-3.5g/l), and the binding agent is (Ec0.06-0.16mol/L). It can be used in Pure gold plating is replaced on the nickel-phosphorus alloy layer, making the coating smooth and crystallized. The pH value of the plating solution is generally between 4-5, and the control temperature is 85-90 degrees Celsius.
3. Post-processing: Post-processing is also an important link. For printed circuit boards, it generally includes: scrap gold washing, DI washing, drying and other steps. If conditions permit, horizontal plate washing can be used to further wash the immersed gold board. Wash the plate and dry it.
The steps of electroless gold plating vary depending on the process, and generally include the following steps:
1. Pretreatment: including oil removal, activation and other steps to prepare for subsequent chemical gold plating.
2. Electroless gold plating: On a pre-treated surface, gold ions are reduced to metal through a chemical reaction and deposited on the surface.
3. Post-processing: including cleaning, drying and other steps to complete the entire process of chemical gold plating.