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Parkerizing, Surface or Deep?

Need to know if Parkerizing is a surface hardness only, or approximately how deep it penetrates, and does it depend on the "Rockwell" hardness of the metal used, such as on handguns.

Bill Kline
- Groom, Texas
2000

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Bill, Parkerizing is a trade name for Manganese Phosphate. The process deposits a Manganese rich coating on the surface of the steel to provide corrosion protection and lubricity. The coating also has pores which can hold oil to extend the corrosion properties much longer. As far as hardening the base material, no the process does not affect the hardness but may cause the steel to become more brittle. This could lead to premature failure of the part. Most parts are baked after plating to prevent this. Check out the Metal Finishing Guidebook chapter on phosphate coatings if you need more info.

Jim Conner
Anoplex Software

Mabank, Texas USA

2000

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Parkerizing is a very proprietary finish. Regular manganese phosphate has rather large crystal structure. A parkerized weapon has a very thin and apparently an extremely fine crystal. It does not significantly "penetrate" the surface of the metal, but done properly is very adherent. Its beauty is the extremely fine layer of oil that it can hold which will provide years of protection to a properly maintained weapon. Mine is over 40 years old.

James Watts
- Navarre, Florida
2000