Problems with electroless nickel plating

A. There is often a notion when facing plating problems that more is needed: more rinsing, more activation, more time, more concentration, etc.

I see this often at my own shop -- the first sign of adhesion problems and the process gets infinitely more complicated. This is often NOT the direction necessary and yours may be one. With hardened steel parts, particularly those whose substrate develop a carbon smut upon acid immersion or activation, the best pretreatment is vapor degreasing followed by abrasive blasting and directly into the plating bath. If you do have to chemically pretreat, minimize all immersion times and acid concentrations. Once you've raised a carbon smut, good luck removing it chemically and all the ultrasonics in the world aren't going to shake a carbon smut off.

Thanks for a great posting, Milt!

A. The details are skimpy. Is the ultrasonic cleaning getting the surface clean or not? What is the activation, maybe a cyanide desmut? For good adhesion, ASTM B242, 'Standard Guide for Preparation of High-Carbon Steel for Electroplating,' also recommends anodic etching in sulfuric acid solution.

Possibly, the surface is passivating after activation. Try speeding up the rinsing and transferal steps between activation and plating. Use room temperature rinses (DI water immediately prior to EN) and especially, don't let the parts dry.

DIN C75 is similar to AISI 1074.

A. Hello,

I think you can consider to use an organic degreaser, like tri.
Take the products out of the plating line, and then degrease them in the lab and put it back in the plating line and see what happens.
When the organic degreased sample does not fail you know the problem is likely to be found in the degreaser.
Veel plezier!

A. The preferable phosphor content depends on the application.
Low Phos for wear resistance, high for corrosion resistance and mid phosphor is in the midlle of those two.