Detonation-gun thermal spray technique was used to deposit commercial available Ni-20Cr and WC-Co coatings on ASTM A213 TP347H boiler steel. The coated specimens were subjected to air environment at 900°C in laboratory furnace to determine high temperature oxidation resistance. Mass change data was recorded to formulate oxidation kinetics of both the coated specimens. The exposed specimens were assessed by field emission scanning electron microscopy and energy dispersive spectroscopy (FE-SEM/EDS) and XRD analysis. The primary focus of the study is attractive oxidation resistance of Detonation gun sprayed Ni-20 Cr coating over the WC-Co coating on the said steel in the air environment.