Comparative study of thermal barrier coatings for internal combustion engine

Abstract: The paper presents the results of investigation into the thermal fatigue resistance of thermal barrier coatings (TBC). Two groups of double-layered thermal barrier coatings (TBC) were investigated: plasma sprayed with ZrO2-8%Y2O3, Al2O3-40%TiO2 or Al2O3-40%ZrO2 top coats and powder flame sprayed with ZrO2-30%CaO, Al2O3-40%TiO2 and Al2O3-30%MgO. The extent of TBC deterioration experienced in thermal fatigue test was evaluated in the erosion test and SEM examinations. Flame sprayed coatings were found more prone to damage than plasma sprayed ones. The highest thermal fatigue resistance revealed TBC plasma sprayed with PSZ. Numerical calculation with Abaqus 6.7 finite element code was used to calculate temperature and stress variations in the coating throughout the test. Phase stability of plasma sprayed Al2O3-40%TiO2 was evaluated by means of X-ray diffraction method. Thermal growth of oxides at the top coat/bond–coat interface and the decomposition of Al2O3-40%TiO2 were found to be important degradation mechanisms leading to the spallation of coatings in the diesel engine and the petrol engine exploitation tests. [ABSTRACT FROM AUTHOR]