反应等离子喷涂Fe-Al2O3-FeAl2O4复合涂层的反应机理研究

金属/陶瓷复合涂层具有金属的韧性和陶瓷的高强度、高硬度等优点,利用反应等离子喷涂技术将Fe2O3/Al复合粉制备成金属/陶瓷复合涂层,以X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等分析技术研究了该复合涂层的反应机理和涂层性能.结果表明:涂层具有以层状的FeAl2O4、Al2O3为骨架,球形的Fe及部分FeAl为弥散相的复合组织;复合粉体反应形成涂层的过程是分步进行的,而且在熔滴到达基体后部分反应仍继续进行;一定程度上,由于反应过程受到Al元素的扩散限制,同时等离子喷涂的冷却速度较高,使得涂层中主要含有FeAl2O4及少量的FeO.

Reaction Mechanism of Fe-Al2O3-FeAl2O4 Composite Coating Synthesized by Reactive Plasma Spraying

With a view to the good toughness of metal and high strength of ceramic effectively combined in cermet coatings, the cermet coating was fabricated from Fe_2O_3/Al composite powders using reactive plasma spraying. The reaction mechanism and properties of the resulting cermet coating were analyzed by means of X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. It was found that the Fe_2O_3/Al cermet composite coating is composed of lamellar FeAl_2O_4 and Al_2O_3 as the skeleton and spherical Fe and a small amount of FeAl alloy as the dispersive phase. Moreover, the reaction during the synthesizing of the composite coating was characterized by step-step reaction, and it proceeded even after the droplets reached the substrate. In addition, since the reaction was dependent on the diffusion of Al element to some extent and composite coating had a high cooling rate during the synthesis process, the coating had FeAl_2O_4 as the main composition and a small amount of FeO as well.