if no deposition, then the causes will be:

1. Overstabilization

Solution: Dilute bath, avoid large additions of replenishers

2.Improper substrate surface

Solution: Substrate may not be autocatalytic and require a nickel or copper strike, i.e., stainless steel, copper

3) Too low temperature or pH

Solution: Analyze and correct

4) Metallic contamination

Soultion: Electrolytically dummy solution

Non-catalytic part .

Not all metals will act as a catalyst to start the plating reaction

Solutions: 1. Use an electrolytic nickel strike prior to electroless plating to make the surface catalytic.

2. Touch off” the reaction using a plating part. The contact between the non-catalytic part and the plating part results in an electron transfer that will start the plating reaction. This method is not recommended for new lead free stabilized EN technologies

3. Use DC current to “jump start” the reaction. A few amps per square foot cathodic (direct) current will start the plating reaction

4. Use a catalytic pre-dip, such as palladium.

5. Use a specially formulated electroless strike based upon DMAB or similar which would have some advantages in many niche applications.

Regard Zia Ullah Khan