激光重熔对金属陶瓷Mo-ZrO_2组织和耐蚀性能的影响  

Effects of Laser Remelting on Microstructure and Properties of Mo-ZrO_2 Cermet

作　　者：刘欢[1] 罗立平[1] 王丁丁[1] 张延军[1] 夏青[1] 

机构地区：[1]核工业理化工程研究院激光技术研究所,天津300180

出　　处：《中国表面工程》2015年第5期93-99,共7页China Surface Engineering

摘　　要：针对金属陶瓷Mo-ZrO2抗液态铁腐蚀问题,采用CO2激光器对金属陶瓷Mo-ZrO2进行表面重熔。采用X射线衍射仪和扫描电子显微镜分析重熔后金属陶瓷表面的相组成和形貌,用光学显微镜和SEM分析测试了重熔层厚度和孔隙率。结果表明:在激光快速加热和冷却作用下,Mo-ZrO2表面大部分金属钼以MoO3的形式挥发,氧化锆经熔化、凝固,在表面形成以柱状晶为主的氧化锆重熔层;重熔层的厚度随着激光能量密度增大而增大,最大可达430.2μm;随着激光能量密度增加,重熔层孔隙率出现先增加后降低的变化,最低达到4.29%;重熔层与基体的结合强度,随着激光能量密度的增加而递减;当激光能量密度为4J/mm2,最大结合强度为17.33 MPa。在1 650℃高温条件下,进行6h熔融金属腐蚀试验,激光重熔使金属陶瓷降低了Mo和Zr元素向熔池扩散速率,显著提高金属陶瓷Mo-ZrO2抗液态铁腐蚀性能。To solve the corrosion problem between Mo-ZrO2 cermet and molten Fe, the surface of cermet Mo-ZrO2 was remelted by COz laser. The microstructure and composition of the remelted layer were studied by X- ray diffraction （XRD） and scanning electron microscope （SEM）. The thickness, porosity of the remelted layer were studied by optical microscope （OM） and SEM. Result show that the surface of Mo-ZrO2 cermet is heated and cooled rapidly, and the men- tal Mo is almost translated into MoO3 and gasified rapidly. The cermet ZrO2 is melted and frozen again. The ZrO2 melted layer consisiting of columnar grain is formed on the surface of cermet Mo-ZrO2. As the laser power density increases, the thickness of the remehed layer also increases, the bonding strength of remehed layer decreases however the porosity of remelted layer first increased and than decreases. The largest thickness of the remelted layer was 430.2 μm, and the least porosity of remelted layer is 4.29 %. When the laser power density is 4 μmm2 , the largest bonding strength is 17.33 MPa. The cermet Mo-ZrO2 and remelted Mo-ZrO2 are corrupted by molten metal at 1650 ℃ for 6 h. The speed of metal Mo and ZrO2 power diffusing from cermet to molten metal is depressed significantly using CO2 laser remelting, Which effectively improve the property of corrosion of Mo-ZrO2 cermet.

关 键 词：金属陶瓷 激光重熔 结合强度 柱状晶 

分 类 号：TG174.44[金属学及工艺—金属表面处理] TG113.23[金属学及工艺—金属学]