采用超音速等离子弧喷涂设备在35Cr Mo钢基体上制备了Zr O_2/Co Ni Cr Al Y热障涂层,并将涂层加热到1 150℃进行氧化试验。利用扫描电子显微镜和X射线衍射方法对涂层的组织结构和相组成进行了分析,并对元素扩散情况进行研究。结果表明,涂层组织致密,界面结合良好,无剥落;粘结层表面存在少量尖角和钩状突出颗粒。热障涂层经过1 150℃加热后,在粘结层与陶瓷层的界面处出现少量深颜色的热生长氧化物(thermally grown oxide,简称TGO);随着氧化时间的延长,TGO层厚度明显增加并且开始连续。通过对Zr O_2-8Y2O3/Co Ni Cr Al Y界面扫描发现,该处Al元素出现了的富集峰,而Cr和Ni元素的含量远小于金属黏结层中含量,并且Cr和Ni元素的变化趋势为沿界面呈梯度下降,TGO层由亚稳态的θ-Al2O3逐渐转变为稳定态的α-Al2O3,有效地提高了涂层的抗高温氧化性能。
Yttria-stabilized zirconia( YSZ) coatings were deposited by low pressure plasma spray( LPPS) in 1.0× 10~4 Pa,1.5 × 10~4 Pa,and 2.5 × 10~4 Pa. Both in-flight particle diagnostic detected by DPV-2000 system and ANSYS-FLUENT software were used to study the connection between the parameters of flying particles and the coating formation,which might help to recognize the relationship between the operation parameters and the coatings quality. The results of simulation showed that particles in a lower spray pressure could achieve a higher velocity. The particle velocity was around 380 m/s at a distance of 35 cm from the nozzle at 1.0 × 10~4 Pa while only 300 m/s at 2.5 × 10~4 Pa in actual measurement.The results showed that the velocity of particles increased with decreasing the spray pressure,which might enhance the flattening rate of coatings and thereby decreased the porosity. The deposited YSZ coating with the lowest porosity can be gained under 1.0 × 10~4 Pa condition.
