Volume 9, Issue 5 (September 1981)
Hydrogen Embrittlement of Zinc Coatings
A brief review is given of hydrogen embrittlement of zinc-coated steel. Most of the steel that is hot dip galvanized is low carbon grade and, as such, little if any hydrogen embrittlement is incurred. Much of the steel that is electroplated is higher carbon grade and, thus, possibly subject to this problem. Methods of overcoming this are suggested. Most of the study on the subject has been with still plating; very little has been done with barrel plating.
An investigation on the effect of alkaline zinc electroplating on embrittlement of hardened parts under barrel plating conditions is reviewed. A pertinent consideration was the verification of previous observations that the use of zincate solutions reduce hydrogen embrittlement compared to those formulated with cyanide. Although many techniques have been used to measure the hydrogen embrittlement level, a simplified bend test with inherent advantages was used here.
A description of cathode surface preparation and embrittlement testing is discussed. Results are analyzed and interpretation of this is developed.