消失模镁合金表面合金化/陶瓷化复合层研究

Research on magnesium alloy surface alloying/ceramic composite layer by evaporative pattern casting technology

采用消失模铸造工艺,进行了镁合金表面制备合金化/陶瓷化复合层研究。选用金属铝粉作为合金化主要元素,PbO-ZnO-Na2 O系低温玻璃粉为制备陶瓷涂层的主要材料。在真空度为-0.06 MPa,温度为800℃条件下浇注,在基体的表面形成了一定厚度合金化/陶瓷化复合层,用来提高基体的耐磨和耐蚀性。扫描电镜、线扫描分析、能谱分析用于研究复合层的微观组织结构和成分分布。与单一的表面陶瓷化相比,表面的陶瓷层和合金层形成良好的结合界面。显微硬度测试表明,从表面至基体复合层的硬度成梯状分布,硬度值的变化与单一的陶瓷层相比有一个过渡区,合金层有利于提高表面陶瓷层与基体的界面结合质量。

Evaporative pattern casting（EPC） process was employed in the investigation of preparing alloying/ceramic composite layer on magnesium alloy surface.Aluminum powder was chosen as the alloying element,and PbO-ZnO-Na2O system low melting point glass powder was used as the material to prepare ceramic coating.The composite layer with a certain thickness formed under vacuum degree of-0.06 MPa and pouring temperature of 800 ℃,which can be used for improving the wear resistance and corrosion resistance of magnesium alloy.Scanning electron microscopy（SEM）,line composition scanning and energy dispersive X-ray spectrometer（EDS） were used to analyze microstructure and composition distribution of the composite layer.It is found that the bonding strength of interface between the alloying layer and surface ceramic coating is much higher than that of the single surface ceramic coating.The hardness test shows that micro-hardness of the composite layer presents a gradient distribution,with a transition region from the surface ceramic coating to the substrate,the alloying layer is beneficial to improve the bonding interface quality between the surface ceramic coating and the substrate.