H2 T his is the same reduction reaction in which Nickel ions change to solid nickel. The formation of hydrogen increases as the pH decreases. Low pH has many negative effects. It is caused when the bubble sticks to the surface of the stamper and prevents plating on the surface covered by the bubble. Bubbles are prevented from sticking to the surface by rotational agitation and by the addition of wetting agents which lower the surface tension of the solution.
T here are a wide variety of plating solutions that can be used for nickel plating.
The solution is extremely important and is usually determined by the needs of the finished product. For CD stamper production, the most popular is the nickel sulfamate solution. N ickel sulfamate has many advantages over other nickel plating solutions such as low internal stress in the deposit, high rates of deposition, and better throwing power. S tress are forces within the deposit which bend the layer convex or concave. If the stamper edges bend upward away from the information side, the layer has tensile stress.