Volcanic ash ingested by jet engines can damage conventional Y2O3-stablized ZrO2 thermal barrier coatings (TBCs) used to protect engine parts in the hot section. Newer TBCs, one based on Gd2Zr2O7 and another composed of ZrO2 solid solution containing Y2O3, Al2O3, and TiO2, are found to be highly resistant to such damage from Eyjafjallajokull volcano ash. Photo courtesy of Peter Greenfield.