Where the
world gathers for metal finishing
Q&As since 1989


-----

Non-polluting alternative to Phosphating for pump parts?

Q. 1) We are phosphating a few pump parts called a) Cam ring (powder metal) b) End cover (SG 500 / 7 iron) both are always immersed in oil but come in to contact with sliding parts. Do we need to phosphate these at all (considering this being a polluting process)?

2) What is an effective alternative non polluting process?

G. Muralidharan
steering systems - Chennai, TamilNadu, India
2002

---

A. Hi, Muralidharan. Yes, in my opinion you must phosphate these pump parts. I was involved in half a dozen manganese phosphatization installations for American manufacturers, which produced millions of reliable engine, auto, and earth moving equipment parts. Phosphating is an essential treatment to prevent scoring and galling during the break-in period even though the parts are immersed in oil; plus, oil runs off the parts and phosphatization doesn't. You don't want your customers to leave their new car at an airport for a month and then have things seize when they try to start it :-)

But why do you say that phosphating is a "polluting process"? All processes are "polluting processes" if you let the waste products out into the environment and "non-polluting processes" if you don't. The tiny amount of phosphatization products on scrapped parts surely can't be a problem; and phosphate is certainly not nearly as toxic or noxious as alternative chemical treatments like terne plating.

True pollution would be to once again fill the junk yards of the world with oily scrap by throwing away the fabulous progress we have made in the last few decades of doubling and tripling the lives of automobile parts. Good luck, and I hope you are not under unbearable pressure towards producing inferior parts and polluting our world with scrap by avoiding such an extraordinarily effective and proven surface treatment as phosphatization :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002