Crevice corrosion occurs when stagnant liquids get underneath of areas where liquid flow can’t reach. Severe pitting can occur, often unseen because something covers them (as in the case below), and can lead to unexpected failures. ASTM G78 testing is one of the methods for determining the susceptibility to crevice corrosion.
G2MT Labs provides ASTM G78 testing, which is the standard practice (1) for evaluation of crevice corrosion in iron and nickel-base stainless alloys in seawater and chloride environments. Washers are used to create multiple crevices on either sides of the corrosion coupon, which are then immersed in testing solutions for given time period, then removed and analyzed (2).
The ASTM standard G78 is the “Standard Guide for Crevice Corrosion Testing of Iron-Base and Nickel-Base Stainless Alloys in Seawater and Other Chloride-Containing Aqueous Environments” and has been widely used to analyzed stainless alloys.