NiCrAlY plasma sprayed coatings: A critical review

Plasma spray coating has emerged as one of the better methods of coating to provide significant resistance to wear and corrosion. The coating of NiCrAlY particles has shown superior bond strength, low porosity, and resistance to erosion-corrosion on various types of substrate materials. The secondary phase particles like B 4 C, Al 2 O 3 , Re, Cenospehere, and WC-Co in the NiCrAlY particles makes it high residence to wear at elevated temperatures at 800°C and 900°C. This makes them special to be used in the wide range of applications, including gas turbines, boilers, shovel blades, and airplanes. Use of these secondary phase particles in the NiCrAlY coatings leads to increase of 76% of hardness due reduction in the porosity of the coatings. A wealth of literature exists about high-velocity oxy-fuel and plasma spray, as well as plasma spray coating techniques. In recent years, efforts have been made to superalloy substrates in the application of turbine blades and boiler tubes with various nano- and micro-particle compositions of new coatings. The present article concentrates mainly on the review and critical analysis on NiCrAlY coating and its characteristics. • Plasma spray coating is found to be effective in coating nano/micron particles • NiCrAlY composite coating plays significant role in high temperature applications • The micro NiCrAlY with nano particles resist corrosion and erosion of substrate • The nano particle reinforcement in NiCrAlY matrix provides high wear resistance