Letter 40090

Thick Ni-P layer  

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I am looking for some info about thick Ni-P (P wt.% >11%).
I would like to let the deposited layer more than 150 um, or more than 300 um.
is there any method to prevent the pinholes on the thick EN surface?

is it possible that electroplating method can get the thick EN with more than 11 wt.% P and without pinhole?

thank you,

Becker Chian
- Taipei, Taiwan

Pinhole free high phosphorus type EN coatings are possible, but require that the substrate also be free of defects (like pores and inclusions) that will initiate pinholes or other coating defects.

EN coatings of 250 - 300 um are commonly plated for salvage of worn or mismachined parts without difficulty. With these thick coatings it is helpful to mechanically agitate the parts during plating, along with general air agitation of the solution.

Ron Duncan Palm International, Inc. - LaVergne, TN

Ed. note: It is our sad duty to alert the readers to the passing of Ron Duncan on Dec. 15, 2006. For those who would like to know more about him, a brief obituary opened Update No. 13 of our Metal Finishing Industry Update Podcast.

As properly stated by Mr. Duncan pin holes generally come from existing superficial defects. Also, from gas bubbles that adhere to the plated surface (then they look bottom-rounded and bright), from solid particles in the bath due to improper filtration, poor chemistry or poor processing practices. In general, if the corrective measures are not taken, the same results may be expected from an electrolytic NiP process.

Guillermo Marrufo
Monterrey, NL, Mexico