热障陶瓷涂层厚度对活塞的影响

Effect of Coating Thickness of Thermal Barrier Ceramic on Piston

利用喷涂稳定的氧化镁氧化锆等离子体陶瓷涂覆在铝活塞顶部来改善活塞铝基体的温度,同时提高柴油机性能,探讨了涂层厚度对活塞温度场和热应力分布的影响,并且与无陶瓷涂层活塞进行了比较,分析了0.2mm、0.4mm、0.6mm、0.8mm、1.0mm厚度涂层的温度场和热应力。结果发现,涂层活塞的表面温度明显高于无涂层的活塞,并且涂层表面的温度随着涂层厚度的增加而增加,和无涂层的活塞相比,1.0mm涂层厚度活塞的铝基体温度下降了25.47%。随着涂层厚度的增加,最大等效热应力随之减少,热应力最大的地方出现在过渡层第一层的下表面,这个值是铝合金基体的3~4倍,并且可以发现陶瓷层、过渡层以及基体的最大等效应力近乎是涂层厚度的函数。

The plasma-sprayed magnesia-stabilized zirconia coating on an aluminum piston crown is used to improve the temperature of aluminum substrate and enhance the performance of a diesel engine. Effects of the coating thickness on temperature field and thermal stress distributions are studied, including comparisons with results from an uncoated piston. Temperature field and thermal stress are analyzed for various coating thicknesses of 0.2 mm, 0.4mm, 0.6 mm, 0.8 mm and 1.0 mm. It is observed that the surface temperature of the coated piston is obviously higher than that of the uncoated one and the coating surface temperature increases with the increase of the coating thickness. Comparison with the uncoated piston, the temperature of aluminum substrate decreases by 25.47% on the 1.0mm coating. The maximum Von Mises stress decreases with the increasing coating thickness. Maximum Von Mises stress occures on the lower surface of first layer on the bond coat. Its value is approximately free to four times than the substrate. At the same time, the maximum Von Mises stress on the Ceramic layer, bond coat and the substrate is a function of coating thickness.