摘要
为明确低功率等离子喷涂物理气相沉积(PS-PVD)工艺中涂层的沉积机制,通过80k W级等离子喷涂系统在100Pa压力下实现PS-PVD工艺,并在圆柱状基体上沉积涂层。采用SEM对正面和侧面沉积的涂层显微组织结构进行分析。研究不同工艺条件下涂层显微组织的变化规律。结果表明涂层在侧面的沉积表现为气相沉积特性,涂层断面为柱状结构,表面为纳米结构粒子组成的岛状结构;涂层在正面的沉积表现为气/液混合沉积特性,涂层表面为扁平粒子和由纳米结构粒子组成的团簇组织,断面主要为扁平粒子结构,在扁平粒子中间存在纳米结构层。功率增大,气相沉积的柱状结构直径和长度增大,表面岛状结构尺寸增大,气/液混合沉积的扁平粒子数量明显减小。喷涂距离增大,气/液混合沉积的扁平粒子数量减小。结论是在涂层沉积侧面和正面分别表现为气相沉积和气/液混合沉积特性。在气/液混合沉积中,气相和液相沉积行为各自独立,但液相由于沉积效率远高于气相,会阻止气相沉积的连续进行。功率增大YSZ粒子气相含量增大,气相沉积效率显著增大。在试验范围内随喷涂距离增大,YSZ粒子气化程度提高。
In order to clarify deposition behavior of coatings in low power PS-PVD processes, PS-PVD processes were realized at 100 Pa pressure with conventional 80 k W class palsma systems, by which the coatings were deposited on the cylindrical substrate. The SEM was used to analyse the microstructure of the coatings deposited in the front and side of the substrate. The change rule of microstructure of the coatings deposited at different parameters was also researched. The results show the vapor deposition behavior is shown in the coating deposited at the side location. The cross section morpjology of coating shows columnar structure and the surface morphology shows island structure composed of nano grain.the vapor/droplet deposition behavior is shown in the coating deposited at the front location. The surface morphology shows splat and cluster composed of nano grain and the cross section morphology shows mainly lamellar accumulated structure between which there existed nano layer. With increased power, the diameter and length of columnar structure and the size of island structure increased via vapor deposition, meanwhile the number of splats decreased via vapor/droplet deposition, which same with the increased spray distance. By summarizing, the vapor and vapor/droplet deposition behavior is shown in the coatings deposited at the side and front location. During the vapor/droplet deposition, the vapor deposition and droplet deposition is respectively independent. However, the droplet may prevent ongoing of vapor deposition because of its much higher deposition rate. With increased power, the content of YSZ vapor and the deposition rate increased significantly. The evaporation degree of YSZ particles increased with the increasing of the testing spray distance.
出处
《热喷涂技术》
2016年第1期44-50,共7页
Thermal Spray Technology
基金
973国家重点基础研究计划(2012CB625100)
国家自然科学基金(51342003)
