Impact of Water Vapor on the High Temperature Oxidation of Wrought and Selective Laser Melted (SLM) AISI 316L

This work focuses on the high temperature oxidation of AISI 316L produced by Selective Laser Melting (SLM) and by conventional metallurgy (wrought), used as reference. Oxidation tests were performed at 900 degrees C for up to 3000 h in laboratory air and up to 1000 h in wet air (air-10 vol.% H2O). X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectrometry were used for the characterization of the corrosion products. SLM specimens exhibit a better oxidation resistance in both atmospheres. SLM samples exhibit parabolic behavior (k(p) = 1.7.10(-13)g(2).cm(-4).s(-1)) throughout 3000 h in air while wrought (k(p) = 1.4.10(-13)g(2).cm(-4).s(-1)) samples undergo breakaway oxidation after 1000 h of exposure. These observations are emphasized in wet air, since wrought coupons present catastrophic oxidation after 100 h, while parabolic behavior (k(P) = 7.0 . 10(-14)g(2).cm(-4).s(-1)) is observed all along the 1000 h exposure for SLM samples. The better behavior observed for SLM samples can be explained by the growth of a dense and continuous Cr2O3 protective layer.