Assessment of the Spray Coated Properties for the Thermal Barrier Applied to the Piston Head of an Internal-Combustion Engine

This paper presents an assessment of the properties of three thermal sprayed coatings for a thermal barrier applied to the piston head of an internal combustion engine. Coating (1) has a topcoat of Al₂O₃ and a bond coat of Ni-Cr. Coating (2) has a topcoat of YSZ and a bond coat of CoNiCrAlY. Coating (3) is 316 stainless steel. The investigators conducted thermal cycle tests and tensile pin tests, and evaluated the thermal barrier effect of the coatings. The results showed that coating (3) had no cracks or delamination after the thermal cycle test, while coatings (1) and (2) had partial cracks and delamination. Coating (2) had the highest adhesion strength, and its thermal barrier property was better than that of coatings (1) and (3). In terms of cost and overall evaluation, coating (3) was considered the most reasonable and appropriate thermal sprayed coating for the piston head application.