Nickel-Cadmium coatings problems

We do Sermetal coatings on the HPC disks of the JT3D & JT8D engines and are approved by Pratt & Whitney for that. We are trying to do the Ni-Cad, but we have some difficulties to produce a good sample. We have checked many things in the whole process, but it seems that we have missing something. Could you help in advising what to look for?

Hi, Isam. You have to give us at least a hint about in what way the coating is not acceptable. We just have no way of knowing whether you have a cleaning problem, a nickel plating problem, a cad plating problem, a diffusion baking problem or whatever if we haven't seen a part, a picture, a report, or anything :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

If it has not changed, it is a tough spec to meet as there is a tight range of nickel and of Cd. They are OD chromated and baked to diffuse the coatings and it comes out a beautiful black.
The whole process has to be approved by PWA, including the racks. Typically, you will need to use bleeders and possibly leave out the corner positions to get the vanes to meet the minimum in the center of the blades and not exceed the maximum on the edges.

As Ted says, where are you having the problem?