Pitting Corrosion Behavior of Sintered SUS444 Stainless Steel in MgCl2 Solution

Abstract

The pitting corrosion behavior of sintered SUS 444 stainless steels (P/M specimens) with different kinds of porosity ratios of 13.3, 9.11 and 6.88 % was studied in an aqueous solution containing MgCl2 compared with a conventionally processed SUS 444 stainless steel(I/M specimen). The pitting corrosion potential decreased almost linearly as porosity ratio increased, and the I/M specimen showed the best resistance against the initiation of pitting corrosion. The pitting corrosion morphology by SEM observation showed that more small pits were observed on the specimen with larger porosity ratio while less number but larger diameter pits were observed on the specimen with smaller porosity ratio, and it was also confirmed that the I/M specimen had the least number but the largest and deepest pits.