Adding an appropriate amount of additives to a specific nickel plating solution can obtain a nickel layer with high stress that is easy to crack and form micro-cracks. This nickel layer is called high-stress nickel.

High-stress nickel is to plate a nickel layer of about 1um on the surface of bright nickel. Due to the high internal stress of high-stress nickel, after it is conventionally plated with a 0.2~~0.3um ordinary chromium layer, the high-stress nickel layer will produce a large number of microscopic particles at the interaction between the chromium layer and the high-stress nickel stress. Cracks, and lead to the formation of uniform micro-cracks on the surface of the chromium layer. Like the nickel seal, the chromium layer becomes micro-discontinuous chromium, but the micro-discontinuous chromium is obtained by high stress. Under the action of the corrosive medium, these cracks form countless micro-batteries, so that the corrosion current is dispersed in the micro-cracks, so that The corrosion performance of the entire coating is significantly improved.