SHS火焰喷涂Al_2O_3基复相陶瓷涂层机理

MECHANISM OF SHS REACTIVE FLAME SPRAYING Al_2O_3-BASED MULTIPHASE COATING

采用SHS反应火焰喷涂工艺,以氧-乙炔火焰为辅助能源,引发Al与CuO间的高能自蔓延反应,在钢基表面制备了Al2O3-Al2Cu3复相陶瓷涂层。对经淬熄实验获取的飞行粒子的形态进行了观察,对涂层进行了物相与组织结构分析。针对喷涂条件下Al-CuO团聚体自蔓延反应的能量状态和喷涂粉体特定的物理与几何特征,提出了SHS反应喷涂的基本过程:各团聚颗粒构成独立的微小反应单元,经历反应孕育、飞行燃烧、碰撞、结构转变与凝固4个阶段形成目标涂层。围绕这一基本过程详细讨论了其中的反应机理、结构形成与凝固行为、组织形态及其成因以及各个阶段的控制因素。

The Al_2O_3-Al_2Cu_3 multiphase coating was produced on an iron substrate by means of SHS reactive flame spraying with Al and CuO as main reactants ignited by the oxyacetylene flame. The morphology of the particles that were quenched and gathered up at different flying distances was observed.The constituent and microstructure of the coating were analyzed.The essential procedure of SHS spraying was summarized with regard to the special conditions of SHS chemical energy between Al and CuO and the physical and geometrical features of aggregated particles. It is concluded that the aggregated particles, acting as solo reactive units respectively, form into coating after going through four successive stages——pregnant reaction, flight combustion, collision, structure transformation and solidification. On the basis of this essential procedure, the reactive mechanism, structure transformation, solidifying behavior, microstructure and dominant factors in each stage were discussed in detail.