Summary for phosphorous content en plating Discussion
Phosphorous content of EN plating is the central question, but the thread makes clear that “medium” and “high” phosphorus are usually treated as distinct ranges, so there is no standard in-between category unless a specific process or specification defines one. In his reply, Ted Mooney advises Eugene Luna to state the exact phosphorus percentage or desired property, because the answer depends on the actual bath and application. On plating speed, he notes that Gawrilov says many factors affect electroless nickel deposition and that they are interrelated, but temperature is the single most important driver. He also cites Mallory’s charts showing that higher pH increases plating speed while lowering phosphorus content, which suggests that higher phosphorus generally comes with slower deposition. The practical takeaway is that the relationship between phosphorus level and plating time depends on the process chemistry and operating conditions.
Q. Hi. Just like to have inquiry regarding Phosphorous EN content. Is it possible to have a phosphorous content for EN between Medium and High phosphorous? Is there an effect on plating time?
Eugene Luna
– Cabyao Laguna Philippines
A. Hi Eugene. Welcome.
I see that this is your first posting here, so I will suggest to you as we do other first-timers, that you will invariably get better answers quicker when you post your own personal situation rather than casting the proposition in the abstract.
For example, if we accept medium phosphorous as 5-9%, and 10%+ as high phosphorous [these numbers are taken from James R. Henry’s “Electroless (Autocatalytic) Plating” chapter of the lMetal Finishing Guidebook], there is no “in between”. So we already don’t know what you want. What percent phosphorous (or what special quality) are you seeking?
As for speed, Gawrilov spends 11 pages on the factors that affect speed just in the acid hypophosphite solutions, saying they are all interrelated, and often contradictory in the literature. But he claims that since temperature provides the energy, it is the single most important factor. What is your situation and are you operating at the maximum possible temperature? Are you formulating your own process, or using a proprietary process whose technical data sheet you can follow?
Mallory simplifies with one chart showing that the higher the pH, the faster the plating speed, and another chart showing the higher the pH, the lower the phosphorous content … which implies that the higher the phosphorous, the slower the speed. Thanks, and good luck.
Regards,
Ted Mooney, P.E.
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