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 800 degrees C 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.