Nickel Plating
- Purpose: The nickel-plated layer serves as a protective barrier between the copper and gold layers, preventing the diffusion of metals and ensuring solderability and the longevity of the PCB. It also enhances the mechanical strength of the gold layer.
- Process Parameters:
- – Addition of nickel plating additives: Typically added based on the method of thousand ampere hours or the actual production board effect, with an approximate addition amount of 200ml/KAH.
- – Current calculation of pattern nickel electroplating: Generally calculated as 2 ampere/square minutes multiplied by the plated area of the board in meters.
- – Nickel cylinder temperature maintenance: Kept between 40-55 degrees, with an ideal temperature of around 50 degrees, necessitating a heating and temperature control system.
Gold Electroplating
- Purpose: Gold offers superior characteristics such as weldability, oxidation resistance, corrosion resistance, low contact resistance, and alloy wear resistance.
- Citric Acid Gold Bath: Widely utilized for its easy maintenance and user-friendly operation.
- Control parameters: Gold content – approximately 1 g/L, pH value – around 4.5, temperature – 35 degrees, specific gravity – about 14 Baume degrees, and current density – roughly 1ASD.
- Main additives: Acid-type and basic-type adjustment salts for pH regulation, conductive salt for specific gravity adjustment, and supplementary additives for gold plating and gold salt.
- Post-plating procedures: Utilize pure water wash for recovery, replenish the gold vat liquid level due to evaporation, and utilize a citric acid dip tank to reduce pollution and ensure stability.
- Anode material: Platinum-plated titanium mesh is recommended for the gold cylinder to prevent contamination and defects during the gold plating process.
- Maintenance: Implement continuous filtration using a carbon core to combat organic pollution and timely replenish gold plating additives.
