Oxidation resistance of uncoated & detonation -gun sprayed WC-12Co and Ni-20Cr coatings on T-22 boiler steel at 900°C

Abstract

Oxidation is the major degradation problem in aircraft, marine, coal fired boilers, factories, and sand-bar gas turbines. It is due to the usage of variety of fuels coupled with elevated working temperatures, which dominances to the degradation in all the applications. In the present investigation oxidation behavior of uncoated and detonation Gun sprayed WC-12Co and Ni-20Cr coatings on T-22 boiler steel has been investigated at 900°C in Silicon wire tube furnace for total duration of 50 cycles under cyclic condition, each cycle consisted of keeping the samples for 60 minutes at 900°C temperature followed by 20 minutes cooling at room temperature. Oxidation kinetics of uncoated and coated sample has been established with the help of weight gain measurements. The exposed samples were characterized by scanning electron microscopy/energy dispersive spectroscopy (SEM&EDS).The Ni-20Cr coating, with morphological observations was found to be more protective than uncoated and WC-12Co coated on T-22 boiler steel.