Effect of Pt modification on hot corrosion resistance of NiCrAlYSi+AlY coating at 900 ℃

In this study, the NiCrAlYSi+Al coating, NiCrAlYSi+AlY coating and Pt modified NiCrAlYSi+AlY coating were prepared on Ni-based superalloy. All three types of coatings were primarily composed of β phase and α-Cr phase. The hot corrosion behaviors for three coatings were investigated at 900 ℃ in the mixed salt of 25 wt % NaCl + 75 wt % Na2SO4. After 120 h hot corrosion, the final mass gain for NiCrAlYSi+Al coating, NiCrAlYSi+AlY coating and Pt modified NiCrAlYSi+AlY coating was 4.62 mg/cm2, 4.01 mg/cm2 and 2.79 mg/cm2, respectively. The Pt modified NiCrAlYSi+AlY coating showed an enhanced hot corrosion resistance due to the Pt addition decreasing the hot corrosion rate and improving the adhesion of alumina scale. Moreover, the Pt modified NiCrAlYSi+AlY coating showed the slightest internal oxidation and sulfidation among three coatings after hot corrosion test.