Influence of Heat Treatment and Sealing on Hot Corrosion Behavior of 80Ni-20Cr Coatings

摘要

The present work aims to examine the influence of heat treatment and sealing on high-temperature hot corrosion performance of HVOF-deposited 80Ni-20Cr coating on T347H austenite steel. The high-temperature corrosion performance of T347H, 80Ni-20Cr, 80Ni-20Cr heat-treated and 80Ni-20Cr sealed coatings has been investigated in Na2SO4-60V(2)O(5) atmosphere at 750 degrees C for 50 cycles. Corrosion kinetics were measured by weight change calculations after each cycle. Bare T347H steel experienced severe spallation of the oxide scale indicating weak resistance toward high-temperature hot corrosion. 80Ni-20Cr coatings have given a significant protection to austenite steel due to the development of oxides and spinels of Ni and Cr. Further, the post-treated by way of heat treatment and sealing improved the corrosion resistance of 80Ni-20Cr coating. Both the post-treatments lead to choking the interconnected porosity of the 80Ni-20Cr coating, which resulted in better performance of post-treated coatings.