Comparison of Oxidation and Microstructure of Warm-Sprayed and Cold-Sprayed Titanium Coatings
Comparison of Oxidation and Microstructure of Warm-Sprayed and Cold-Sprayed Titanium Coatings
复制标题
DOI：
10.1007/s11666-011-9703-4
复制
发表时间：
2011-09
影响因子：
3.1
通讯作者：
Keehyun Kim;S. Kuroda;M. Watanabe;Renzhong Huang;H. Fukanuma;H. Katanoda
中科院分区：
文献类型：
--
作者：
Keehyun Kim;S. Kuroda;M. Watanabe;Renzhong Huang;H. Fukanuma;H. Katanoda
通过温喷涂（WS）和冷喷涂（CS）工艺制备厚钛涂层，以研究涂层的氧化和微观结构。在形成涂层之前，对飞行中的钛粉末颗粒的温度和速度进行了数值计算。使用较高气体温度条件和低氮气流量的 WS 工艺中发生了显着的氧化，将氮气与高速氧燃料 (HVOF) 喷枪的火焰喷射混合以控制推进剂气体的温度。然而，随着氮气流量的增加，氧化显着减少。在使用氮气或氦气作为推进剂气体的 CS 工艺中，几乎没有观察到氧化。即使扫描电子显微镜或 X 射线衍射方法没有检测到使用高氮气流量的 WS 或使用氦气的 CS 产生的涂层中的氧化物，惰性气体熔融方法也显示氧含量从 0.01 wt.% 轻微增加到 0.2 wt.%。传统机械抛光制备的涂层横截面大部分看起来致密。然而，通过离子铣削方法制备的横截面揭示了包含小孔和沉积颗粒之间无界界面的实际微观结构。
Thick titanium coatings were prepared by the warm spraying (WS) and cold spraying (CS) processes to investigate the oxidation and microstructure of the coating layers. Prior to the coating formations, the temperature and velocity of in-flight titanium powder particles were numerically calculated. Significant oxidation occurred in the WS process using higher gas temperature conditions with low nitrogen flow rate, which is mixed to the flame jet of a high velocity oxy-fuel (HVOF) spray gun in order to control the temperature of the propellant gas. Oxidation, however, decreased strikingly as the nitrogen flow rate increased. In the CS process using nitrogen or helium as a propellant gas, little oxidation was observed. Even when scanning electron microscopy or an x-ray diffraction method did not detect oxides in the coating layers produced by WS using a high nitrogen flow rate or by CS using helium, the inert gas fusion method revealed minor increases of oxygen content from 0.01 to 0.2 wt.%. Most of the cross-sections of the coating layers prepared by conventional mechanical polishing looked dense. However, the cross-sections prepared by an ion-milling method revealed the actual microstructures containing small pores and unbounded interfaces between deposited particles.