Effect of TiO_2 content on properties of Al_2O_3 thermal barrier coatings by plasma spraying

TiO_2含量对等离子喷涂Al_2O_3热障涂层性能的影响(英文)

Al2O3 thermal barrier coatings with different TiO2 contents were deposited on 6061 aluminum alloy by plasma spraying. The corrosion resistance, thermal insulation property and phase composition of these coatings were investigated. The results indicate that all the feedstock powders exhibit phase transformation during the spray process. With the increase of the TiO2 content in the powder, the corrosion resistance of the coating is enhanced but the thermal insulation property is decreased. This can be attributed to the higher thermal conductivity but lower melting point and brittleness of TiO2 than those of Al2O3, so it is easy for TiO2 to disperse in the brittle Al2O3 substrate during spraying, in which these dispersively distributed TiO2 play the role of hole sealing, releasing stress and reducing cracks.

采用等离子喷涂技术在6061铝合金表面制备了不同含量TiO2的氧化铝陶瓷涂层,研究了涂层的相组成、隔热性能及耐腐蚀性。实验结果表明:在喷涂过程中陶瓷层中均有物相的转变。随着粉末中TiO2含量的增加,涂层的耐腐蚀性增强但是隔热性下降。这可能是由于TiO2的导热系数比Al2O3的导热系数高,但其熔点比Al2O3的熔点低,同时脆性较小,在喷涂过程中,TiO2弥散分布在脆性的氧化铝基体中起到了封孔及释放应力、减少裂纹的作用。