Assessment of Hot Corrosion in Molten Na2SO4 and V2O5 of Inconel 625 Fabricated by Selective Laser Melting versus Conventional Technology

• Published in: Materials Vol. 15; no. 12; p. 4082
• Main Authors: Badea, Teodor Adrian, Batalu, Dan, Constantin, Nicolae, Paraschiv, Alexandru, Pătroi, Delia, Ceatra, Laurentiu Constantin
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 08.06.2022; MDPI
• Subjects: Additive manufacturing; Cooling; Corrosion rate; Corrosion resistance; Corrosion tests; Grain boundaries; Hot corrosion; Inconel 625; Laser beam melting; Lasers; Molybdenum; Nickel base alloys; Raw materials; Scanning electron microscopy; selective laser melting; Sensors; sodium sulphate (Na2SO4); Superalloys; Vanadium pentoxide; vanadium pentoxide (V2O5); United Kingdom > UK; Germany; Romania
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15124082

Inconel 625 samples, obtained by Selective Laser Melting (SLM) and conventional technology, were tested for hot corrosion resistance against a molten mixture of Na2SO4 and V2O5. 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 Cr2NiO4 compound, which acts as a temporary barrier.