Corrosion behaviour of powder metallurgical stainless steels after two years of exposure in atmosphere

Abstract

This work addresses the corrosion behaviour of sintered components manufactured from powders of AISI 316L and AISI 304L stainless steel. The steels were sintered under vacuum or in a nitrogen based atmosphere at temperatures of 1120 and 1250°C. Their corrosion resistance was then analysed by electrochemical techniques and by atmospheric corrosion testing for two years at urban and marine test sites. The results obtained demonstrate the adverse influence of porosity on the corrosion resistance of powder metallurgical stainless steels in natural environments, and validate several important conclusions about the influence of the sintering parameters on the corrosion behaviour. The morphology of the attack on the surface of the stainless steels, and its development within the interior of the material, a frequent consequence of exposure to natural environments, have been studied.