The Ni-Cr based coating was prepared on surface of the TP304 H stainless steel by the plasma powder cladding technology. The microstructure

phase and chemical composition of the coating were analyzed. The influence of temperature on corrosion behavior of the Ni-Cr coating was also investigated in simulated coal combustion environment at 650 ℃ and 750 ℃

respectively. The results show that

the Ni-Cr coating was metallurgically bonded to the substrate and the microstructure of the coating is uniform. The coating prepared was mainly consisted of Fe0.64Ni0.36 and Ni-Cr-Fe. The corrosion of the Ni-Cr based coating in coal ash/gas environment was mainly caused by the accelerating effect of alkali metal sulfate dissolution and volatile corrosion products formed by O

S and cladding in the flue gas. The effect of corrosion temperature on corrosion resistance of the materials was particularly important. The corrosion resistance of the Ni-Cr coating decreased significantly with the increasing temperature. After corrosion for 500 h

the thickness of the corrosion products at 700 ℃ was twice thicker than that at 650 ℃. Obvious intercrystalline corrosion and spallation of corrosion products occurred at 700 ℃. The XRD results indicate that

rich Fe and Cr oxides in were the main corrosion products for all of the samples

while the mount of sulfides increased obviously with the exposed temperature.