粒子飞行速度对热障涂层结构和性能影响

摘要

采用常规等离子喷涂（APS）和超音速等离子喷涂（SAPS）两种工艺制备了热障涂层,研究表明：两种等离子射流中粒子表面温度相近,SAPS工艺中粒子飞行速度达到430m/s,比APS工艺（200m/s）粒子飞行速度提高1倍。由于SAPS工艺中等离子射流速度高,熔融粒子在等离子射流中产生雾化形成尺寸较小粒子,伴随粒子撞击基体的速度提高,增加了熔融粒子撞击基体能量,在基体上形成厚度薄和飞溅少的＂板条＂,加强了＂板条＂与基体或＂板条＂与＂板条＂间结合,消除了APS工艺制备的热障涂层中典型层状结构,使热障涂层结合强度和抗热震性能分别提高40%和1倍。%Thermal barrier coatings were prepared by conventional air plasma spray （APS） and supersonic air plasma spraying （SAPS）. The particles temperature in SAPS plasma jet was closed to APS. The particles velocity was about 430m/s in SAPS plasma jet when the molten particles impacted to substrate, 2 times higher than that in APS stream （about 200m/s）. A number of smaller particles were formed in SAPS jet as a result of extensive shearing by high velocity plasma jet. The impact energy of molten particles to substrate was increased with the particles velocity increase. So the adhesion strength of ＂splat＂ to substrate or ＂splat＂ with ＂splat＂ was enhanced, and the lamella structure that usually was observed in thermal barrier coatings sprayed by APS was eliminated. Thermal barrier coatings bond strength and thermal shock resistance of SAPS coatings was about 40% and 2 times higher than that deposited by APS process.