The studied transitions have been revealed in ceramic materials based on Al₂O₃ and ZrO₂ used to high temperature resistant plasma sprayed coatings. These transitions are caused by two group of factors. First is connected with applied materials which means polymorphism of both oxides and complex composition of studied materials. The second group is connected with involved high temperature processes. Both plasma spraying of the coatings and thermal shock cycling experiments are characterised by short time temperature action and high cooling rate which gives favourite conditions to phase transitions. In the Al₂O₃-TiO₂ system conditions of b-Al₂TiO₅ occurence have been determined. Forms of this compound obtained by plasma spraying and annealing in the furnace differ slightly each other.
Materials based on ZrO2 with addition of rare earth oxides reveal different phase transitions particularly transformation of martensite type between monoclinic and tetragonal crystal modifications.