This invention, intended for use in the processing of turbine engine blades’ thermal barrier coatings, is a two-step procedure used to produce a thermally grown oxide that is completely devoid of lifetime-limiting spinel oxides. Both steps take place at the same temperature used in present day bond coat pre-oxidation, utilize everyday gases, and can be performed serially in the same furnace, in a matter of hours. In step one, pre-oxidation of a bond-coated blade yields a thermally grown oxide (TGO) layer that contains a limited amount of spinel. In step two, all spinel is removed in situ. In an industrial-scale setup, the entire process would take place in less than 24 hours, including ramp times to and from the exposure temperature. Once blade specimens are cooled and removed from the furnace, they are then ready to be coated with the thermally protective yttria-stabilized zirconia (YSZ) layer, using industry-standard techniques. Due to the nature of the process, no new spinel is expected to grow at the critical TGO–YSZ interface for as long as the part operates in service, which means that the blade will be completely spinel-less for its entire usable lifetime. By eliminating all spinel-related failure mechanisms, this may result in longer blade lifetimes and therefore significant cost reduction.