Cyclic Oxidation Behavior of Detonation Gun Sprayed Ni-20Cr Coating on a Boiler Steel at 900°C

摘要

Detonation-gun spray technology provides the possibility of producing high quality coatings with significant adherence strength. In this study, detonation gun spray technique was used to deposit Ni-20Cr coating on a commonly used boiler steel (ASTM-SA213-T-22). The specimens with and without coatings were subjected to cyclic oxidation testing at an elevated temperature of 900°C to ascertain usefulness of the coating. Mass change data was evaluated to formulate the kinetics of the oxidation. The uncoated sample suffered intensive spallation along with a significant overall mass gain. The oxidation rate was found to reduce appreciably after the deposition of the coating as the overall mass gain was reduced by 91%. The exposed specimens were characterized by scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS). It was observed that detonation gun sprayed Ni-20 Cr coating was successful in providing oxidation resistance to the given steel in the air environment.