Electroless Nickel and Stainless Steel

Question:

We have problems with depositing electro-less nickel on stainless steel. The plating doesn’t adhere to the SS substrate. We assume that the problem is with the Woods nickel strike process. The current density we are using is 10 asf.Could you give details about the formulation of the solution and the steps to make Wood’s nickel strike work. S.J.

Answer:

This is a case of properly preparing the stainless steel substrate prior to the electroless nickel plate. There are a number of ways to properly prepare the stainless steel. The following one works well.

 

1. Alkaline clean for 5-10 min
2. Rinse
3. Cathodically electroclean for 2-3 min
4. Rinse
5. Activate with a Woods nickel strike.
6. Rinse
7. Electroless nickel plate

 

There are various formulations for the Woods nickel strike. One formulation, from Solution Software by Lawrence J. Durney, Kushner Electroplating School, www.platingschool.com, consists of 45g/liter of nickel in 10% by vol of commercial hydrochloric acid. The nickel is added as nickel chloride. The bath is used at 10-40 asf at room temperature for 30 seconds to two min. Nickel anodes are used which means the nickel content will increase with use. The nickel content should not be allowed to increase above 75 g/liter. You should compare your process to that given above and determine where your process varies.