One possible explanation for the discoloration of the electroplated gold layer on a PCB could be due to oxidation. When exposed to air and moisture over time, metal surfaces are prone to oxidizing and developing a patina or dark tarnish. This can negatively impact the aesthetic appeal of the PCB and even impact its conductivity if the oxidization is severe enough. Other factors that could contribute to the blackening of the gold layer might include exposure to corrosive chemicals or environmental pollutants. Proper storage and handling measures, along with prompt cleaning and maintenance, can help alleviate these issues and prolong the life of the PCB.
Regular maintenance and carbon treatment of the nickel plating bath is crucial in preventing the formation of flake-like crystallization in the plated nickel layer. This unwanted occurrence can make the nickel layer excessively hard and brittle, causing significant damage to the gold layer on PCBs. To avoid such complications, it is vital to keep a close eye on the condition of the plating bath in your factory's production line and ensure that proper carbon treatment is carried out to maintain a clean plating solution and restore bath activity. Neglecting this critical maintenance can have severe consequences for the quality of your plating process and the long-term health of your products.
Ensuring an adequate performance of the gold layer on PCBs requires a thorough control of the underlying nickel layer's thickness. Insufficient nickel layer thickness can cause discoloration of the gold layer, leading to surface issues. To avoid such problems, factory personnel should regularly inspect the nickel layer thickness, aiming for a thickness of around 5 μm, considered sufficient for optimal results. Therefore, paying attention to the nickel layer thickness is crucial to ensure the overall quality of the printed circuit board.
Now, let's shift our attention to the gold plating bath. By ensuring proper maintenance, filtration, and regular replenishment of the solution, we can achieve a superior level of contamination control and stability compared to the nickel bath. Nevertheless, it is crucial to pay attention to the following aspects:
- The issue at hand is determining whether the addition of gold plating bath replenisher is sufficient or excessive. It is important to carefully evaluate the amount of replenisher being added to avoid any potential problems or complications. It is recommended to follow the manufacturer's instructions and guidelines for optimal results. Adding too much replenisher can result in waste and unnecessary expenses, while insufficient addition can lead to inadequate plating coverage. Therefore, it is crucial to find the right balance between sufficient and excessive addition of gold plating bath replenisher for an effective coating process.
- Control of the solution's pH value.
- Condition of the conductive salts.
To ensure the state of the gold plating bath, it is advisable to utilize an AA machine for an analysis of the solution's impurity content. Additionally, do not overlook the importance of checking whether the filtering cotton in the gold plating bath has been recently replaced. Please note that the generated content should be highly similar to the original text information but rearranged in a different manner.
To prevent the PCB electroplated gold layer from turning black, it is crucial to maintain the plating baths effectively, control the nickel layer thickness, and ensure the stability of the gold plating bath. It is important to frequently monitor and maintain these factors to address this issue. If the problem persists, it may be necessary to conduct a thorough analysis and make adjustments to the production parameters accordingly.