Assessment of Some Chromated and Non-Chromated Primers on Magnesium ZE41A, Aluminum 2024, and Steel 4340 Via Electro-Chemical Impedance Spectroscopy

摘要

Organic coating systems are one of the most efficient methods for protecting metals from corrosion, and the use of chromate primers vastly improves corrosion protection. However, environmental concerns about hexavalent chromium (Cr+6) toxicity have led to the development of many non-chromate coatings. In recent years, water-borne coatings have emerged as viable alternatives and provide the additional advantage of having low content of volatile organic compounds. Since the performance of chromated coatings tends to exceed that of their environmentally friendly counterparts, evaluations of some non-chromate alternatives need to be performed. This report compares the performance of three military primers: MIL-P-23377C (chromated), MIL-P-85582C (chromated), and MIL-P-85582N (non-chromated) on three common military alloys.