Erosion corrosion behaviour and mechanical properties of wire arc sprayed Ni-Cr and Ni-Al coating on boiler steels in a real boiler environment

ABSTRACT

The aim of the current investigation is to evaluate the erosion-corrosion (E-C) performance of wire arc sprayed Ni-20Cr and Ni-5Al coatings on T22 and SA516 boiler steels in a real boiler environment. The microstructure, mechanical properties and high temperature E-C performance of the deposited coatings were investigated. The E-C behaviour of the test samples was determined in the superheater zone of the coal fired boiler at 750^°C for fifteen cycles, where each cycle involved 100 hours of heating followed by 1hour of cooling. Thickness loss data was used to determine the E-C behaviour of the coating. XRD, SEM/EDS were used to analyse the test samples. Ni-20Cr coated SA516 steel decreased maximum E-C rates by 98.05%, while Ni-5Al coated T22 steel reduced E-C by 68.63% than the base steel. This higher E-C resistance is due to the formation of protective phases (Cr₂O₃, NiO and Al₂O₃) and better mechanical properties of the coatings.

KEYWORDS:

• Wire arc spray
• erosion-corrosion
• mechanical properties
• boiler environment
• Ni-20Cr
• Ni-5Al coating

Acknowledgments

Authors are extremely thankful to the RIC Department of IK Gujral Punjab Technical University, Kapurthala, Punjab (India) for giving the opportunity to carry out this experiment work.

Disclosure statement

No potential conflict of interest was reported by the authors.