Nickel Plating
Announcing
Editor
NdFeB nickel plating is actually a multi-layer plating, which needs to be pre-plated with nickel first, then thickened by copper plating, and then bright nickel plated on the surface.
①Pre-plated nickel
Nickel sulfate: 300g/L, pH: 4.O ~ 4.5, nickel chloride: 50g / L, temperature: 50 ~ 60 ℃, boric acid: 40g / L, current density: 0.5 ~ 1.5A / dm2 additives in the right amount of time 5min
②Thickening of copper by pyrophosphate plating. As an intermediate plating, although the popular use of acid bright copper plating process, but for neodymium iron boron materials, thickening plating should not be used acid copper plating, this is because in a strong acidic plating solution, has been pre-plated with cathodic plating layer of porous materials will be very easy to occur in the substrate microscopic corrosion; for the future delayed blistering to leave a hidden danger. A more suitable process is the near-neutral copper pyrophosphate plating.
Copper pyrophosphate: 70g / L, brightener: appropriate amount, potassium pyrophosphate: 300g / L, pH: 8 ~ 8.5, ammonium citrate: 30g / L, temperature: 40 ~ 50 ℃, ammonia: 3mL / L, current density: l ~ 1.5A / dm2.
③ Bright nickel plating nickel sulfate: 300g/L, commercial brightener added according to the instructions, nickel chloride: 40g/L, pH: 3.8 ~ 5.2, boric acid: 40g/L, temperature: 50 ℃, low-foam wetting agent: lmL/L, cathodic current density: 2 ~ 4A / dm2.
For NdFeB materials that need other surface plating, the copper thickening plating of the intermediate plating layer can be completed before the other surface plating is processed. Sometimes, in order to increase the thickness and reliability of the plating, you can also add a fast acid copper plating process after pyrophosphate plating to get a good surface decoration, and then plating other plating will have better results. The main point to carry out these plating operations is to be sure to be charged down the tank and can not be disconnected in the middle of the process, otherwise it will be the role of the plating solution in the pores of the substrate caused by microscopic corrosion, affecting the bonding force.