金属陶瓷覆层-钢基体界面结合状态的研究

Study on bond interface between ternary boride cermet cladding and steel substrate

为提高钢基材料的耐磨性和耐腐蚀性,以金属Mo粉、Fe粉和B-Fe合金粉末为原料,采用原位反应真空液相烧结技术,在钢基体表面制备三元硼化物金属陶瓷覆层.测定了覆层-钢基体界面结合强度及界面结合区的显微硬度变化,研究了界面微观结构和界面区元素分布,并对覆层-钢基体界面层形成的机理进行了分析.结果表明,覆层与钢基体之间的断裂破坏发生于界面附近的钢基体和覆层内,而不是覆层与钢基体之间结合界面的剥离;在覆层-钢基体结合界面处,存在由高硬度覆层到低硬度钢基体的狭窄过渡区,合金元素的分布形成具有一定厚度的过渡层.

In order to increase the wear resistance and corrosion resistance of steel materials, using Mo, B - Fe alloy and Fe powders as raw materials, ternary boride hard alloy clad material was prepared by in situ reaction and liquid phase sintering in vacuum furnace on steel （Q235） substrate. The bond strength between the cladding and the steel substrate of clad material are measured using three-point bending method, and the measured value is 740. 38 MPa. The measured results indicate that a strong bond interface exists between the cladding and the steel substrate. Fracture does not occur at the bond interface, but initiates in the interior of the steel substrate or the cladding in the vicinity of the interface. The micro-hardness, microstructure and element distribution in the vicinity of the bond interface are investigated. It is shown that the cermet cladding has high microhardness. In the vicinity of the bonding interface, there exists a narrow transitional zone, in which the distribution of elements Mo and Fe continuously changes. No clear bonding interface exists between cladding and steel substrate, but a transitional layer with a certain thickness is formed, and become a firm metallurgical bond between cladding and steel substrate. The formation mechanism of the interface between the cladding and the steel is investigated.