Effect of Cr on the High Temperature Corrosion of Al₃Ti-Cr Alloys in SO₂ Atmosphere

Abstract

Three types of L12-type Al3Ti-Cr alloys, of compositions 67Al-25Ti-8Cr, 66Al-24Ti- 10Cr, and 59Al-26Ti-15Cr in atomic percent, were corrosion tested at 900, 1000, and 1100oC in an Ar-1% SO2 gas atmosphere for up to 150 h. The alloys were resistant to corrosion because a thin Al2O3 barrier layer was formed on the alloy surface due to the high Al content in the alloys. Due to the very strong Al affinity for oxygen, virtually no sulfur was detected inside the oxide scale.