Effect of a Ni interlayer on the corrosion behavior of CrN PVD coating deposited onto plastic mold steels

摘要

Plasturgic industry commonly uses for molds, steels containing manganese sulfide(MnS), inclusions. These inclusions act as heterogeneities which make manufacturing easier. Moreover, this alloy is not thermally treated and it is cheap and easily available. Unfortunately, its use in corrosive conditions is banished because of the poor corrosion behavior of the MnS particles. In order to mask these high-sensitive inclusions and to enhance surface mechanical properties, a hard PVD CrN coating, elaborated at two different temperatures, has been performed and coated samples have been tested in saline corrosive solutions by electrochemical techniques. Corrosion results from dissolution of the anodic substrate through coating porosity inherent to the PVD process. The aim of this study is to determine the film corrosion resistance of an underlayer electroless nickel film deposited onto the 40 Cr{sub}2 Mn Mo S substrate coated by PVD CrN.