Characterisation and Corrosion-Erosion Behaviour of Carbide based Thermal Spray Coatings

Thermal spraying has emerged as a suitable and effective surface engineering technology and is widely used to apply wear, erosion and corrosion protective coatings for various kinds of industrial applications.Cr 3 C 2 -based coatings have been applied to a wide range of industrial components.Cr 3 C 2 -NiCr coatings offer greater corrosion and oxidation resistance, also having a high melting point and maintaining high hardness, strength and wear resistance up to a maximum operating temperature of 900 °C.The corrosion resistance is provided by NiCr matrix while the wear resistance is mainly due to the carbide ceramic phase.This paper reviews the performance, developments and applications of Cr 3 C 2 -NiCr thermal spray coatings for corrosion/erosion-corrosion under different types of environments and outlines the characterization of Cr 3 C 2 -NiCr coatings with respect to their microstructure and mechanical properties, together with some brief characterisation work by the author for HVOF sprayed 75Cr 3 C 2 -25NiCr coating on T91 boiler steel.