Evaluation of hot corrosion behavior of HVOF thermally sprayed Cr3C2-35NiCr coating on SS 304 boiler tube steel

In the present work, the commercially available Cr3C2-35%NiCr coating powder is deposited by using HVOF thermally sprayed coating on SS 304 Boiler tube steel. The hot corrosion study is conducted on commercially available Cr3C2-35%NiCr coated SS 304 boiler tube steel and uncoated SS 304 boiler tube steel at 800oC in Na2SO4-60%V2O5 boiler environment with cyclic conditions. The thermo gravimetric method is used to establish the kinetics of hot corrosion by means of weight change method. The commercially available Cr3C2-35%NiCr coated specimen shows very less weight gain as compared to the uncoated specimen. The superior hot corrosion resistance obtained due to the formation of oxide layers consisting of Cr3O3,Cr2O4 &NiO. The uncoated specimen degrades at a faster rate in the form of layer of spalls. The microstructural analysis is examined by using X-ray diffraction (XRD) & scanning electron microscopy (SEM) is used to determine the coating morphology and corrosion products.