Assessment of the properties about the thermal sprayed coatings for the thermal barrier apllied to the internal-combustion engine

Properties of three themal sprayed coatings were compared to select the effective sprayed coating for giving the thermal barrier to the Al alloy components of internal combustion engines. Results for coating 1 (top coat,Al2O3;bond coat,Ni-Cr), coating 2 (top coat,YSZ;bond coat,CoNiCrAlY), and coating 3 (SUS316) are presented below. (1)After thermal cycle testing, no crack or delamination was apparent in coating 3. Partial cracks and delamination were obseved in the top coatibg in coating 1 and 2. (2)All coatings have sufficient adhesion strength. The adhesion strength of coating 2 was especially high. (3)The thermal barrier property of coating 2 was better than that of coating 1 or coating3. (4)Comprehensive evaluation results show that coating 2 has a good thermal barrier property and coating 3 is a reasonable material because of its low cost as a thermal sprayed coating applied to Al alloy components of an internalcombustion engine.