Influence of YSZ Powder Characteristics on the Morphology of PS-PVD Thermal Barrier Coatings

The characteristics of thermal spray powder materials usually impact on morphology of their coatings. YSZ spherical agglomerated powders suitable for PS-PVD was prepared, and the powders with different microstructure were obtained. PS-PVD was carried out using the YSZ powders with different characteristics. Results show that suitable particle size is essentially required to achieve gasification of the YSZ powder in PS-PVD plasma jet. It is usually required that to attain easy vaporization,. D10 of the YSZ powder is not more than 3¦Ìm, D50 is 5-10¦Ìm and D90 is not more than 25¦Ìm. When the particle size range and bulk density of granule are close, and the internal looseness is different, the gasification and deposition effect of the ¡°secondary agglomeration¡± granulated powder after jetting is obviously better than that of ¡°only one agglomeration¡± powder. After the powders were densified to different degrees, the crush strength and bulk density are high, it is difficult to achieve effective gasification. While the crush strength of granule is moderate and loose bulk density of powder is about 1g/cm3, deposition of the powder for making the TBC coatings with desired microstructudres is realized.