Hot Corrosion behaviour of Nanostructured Cermet based Coatings Deposited by Different Thermal Spray Techniques: A Review

Abstract

Hot corrosion is a serious problem in power plants, boilers, gas turbine and internal combustion engines. There are several alloys and super alloys which are capable to protect the components within a certain limit. So many coatings are widely used to improve service life of components by providing better erosion-corrosion resistance to the substrate. This review is essentially based on the hot corrosion behavior of Nanostructured and conventional Cr3C2-NiCr coatings deposited by several thermal spray techniques. This review is done to summarize the various properties of Chrome carbide nickel chrome coatings deposited by different methods and the hot corrosion behavior of both Nanostructured and conventional coatings in molten salts environment.High-velocity oxy-fuel (HVOF) spraying method is effective method to deposit dense and less porous coatings but a new method has been developed known as Detonation gun (D-Gun) coating,deposited by D-gun has low porosity and high bond strength than HVOF. Plasma spray is also thermal spray technique which possess less porosity, high bond strength, good abrasive and wear resistance and high hardness value but the cost of equipment is very high which is the limitation of this method. The main aim of the review is to summarize the performance of Cr3C2-NiCr coatings in various environment and to study the effect of coating parameters such as coating thickness & porosity on the hot corrosion behavior.