Study on thermal barrier coatings deposited by detonation gun spraying

Thermal barrier coatings (TBCs) were obtained using a detonation gun (D-gun) spraying technique on a Ni-base superalloy, M38G. The thermal conductivity of freestanding YSZ coatings and the thermal shock behaviors of TBCs system were studied. The results showed that the D-gun sprayed TBC had a very low thermal conductivity of 1.0–1.4 W/m K, close to that of the plasma sprayed YSZ coatings and much lower than their EB-PVD counterparts. The TBCs exhibited excellent resistance to thermal shock up to 400 cycles of 1050 °C to room temperature (forced air cooling) +200 cycles of 1100 °C to room temperature (forced water quenching). The damage evolution mode of TBC system during the thermal cycling was discussed in the light of the features of microstructural development and phase changes.