Assessment of Hot Corrosion in Molten Na 2 SO 4 and V 2 O 5 of Inconel 625 Fabricated by Selective Laser Melting versus Conventional Technology.

Inconel 625 samples, obtained by Selective Laser Melting (SLM) and conventional technology, were tested for hot corrosion resistance against a molten mixture of Na 2 SO 4 and V 2 O 5 . The assessments were performed in air, at 900 °C with exposure time of up to 96 h, and at 1000 °C for 8 h. Weight gain was higher for samples obtained by SLM, with 37.4% after 8 h, 3.98% after 24 h, 4.46% after 48 h, and 5.8% after 96 h at 900 °C (22.6% at 1000 °C, 8 h). Three stages of corrosion were observed, the first and last with a high corrosion rate, while the second one showed a slower corrosion rate. Corrosion behaviour depends on the morphology of the grain boundary, which can influence the infiltration of corrosive salts, and on the formation of Cr 2 NiO 4 compound, which acts as a temporary barrier.