The invention is directed to a ceramic material for use in thermal barriers for high temperature cycling applications and high temperature abradable coatings. The material is an alloy formed predominantly from ultra-pure zirconia (ZrO2) and/or hafnia (HfO2) that has uncharacteristically high sintering resistance to achieve a high service lifetime and low thermal conductivity to achieve high operating temperatures. In the material, oxide impurities such as soda (Na2O), silica (SiO2), alumina (Al2O3), titania (TiO2), hematite (Fe2O3), calcia (CaO), and magnesia (MgO) make up no more than 0.15 weight percent. The invention provides materials to produce a coating structure so that the changes in the coating microstructure over the in-service lifetime are either limited or beneficial.