Abstract: Hot corrosion resistance of cast alloy K52 and its coating specimens were studied.The oxidation kinetics of the alloys was measured.Scan electron microscopy(SEM)was used to exam the surface morphology and cross-section views of the eroded specimens,and the electro-probe were also adopted to characterize the compositions of corrosion products and distribution of elements on the cross-section.The results indicated that the nanocrystalline coating was destroyed with pre-deposits of 75%Na₂SO₄+25%NaCl for 10h.A continuous inner scale of Al₂O₃ formed on the cast alloy after hot corrosion for 50h.The scale inhibits O,S and Cl entering into alloy.