Coal ash corrosion testing was conducted on six solution-treated nickel-based alloy plates (Alloy 617, Alloy 263, Alloy 740, Alloy 141, HR6W [45Ni-23Cr-7W], and HR35 [50Ni-30Cr-4W-Ti]) intended for advanced-USC boilers, along with conventional ferritic and austenitic stainless tubes for comparison. Tests used synthetic coal ash (Na 2 SO 4 , K 2 SO 4 , Fe 2 O 3 ) with varying SO 2 concentrations (0.02-1.00 vol%). Results showed maximum metal loss at 700°C, with higher SO 2 levels causing increased corrosion. Materials with higher chromium content demonstrated better corrosion resistance, suggesting chromium content is a crucial factor in material selection for these applications.