EROSION-CORROSION BEHAVIOUR OF COLD SPRAY Ni-20Cr COATING ON SA 516 STEEL IN ACTUAL BOILER ENVIRONMENT

摘要

Boiler tubes of coal-fired boilers suffer severe erosion-corrosion (E-C). One method to counteract this problem is by the use of thermal spray protective coatings. Cold spray coating process was used to deposit Ni-20Cr powder on SA 516 (Grade 70) boiler steel. The bare as well as the coated steels were subjected to cyclic experimental studies, in the superheater zone of a coal fired boiler. The weight change technique was used to establish kinetics of the erosion-corrosion. XRD, FE-SEM/EDS and X-ray mapping techniques were used to analyse the as-sprayed and corroded specimens.