论文部分内容阅读
利用喷雾干燥与真空烧结技术制备团聚型ZrB_2-MoSi_2复合粉末,以这些粉末为原料,通过低压等离子喷涂法制备了ZrB_2-30%MoSi_2(质量分数)复合涂层(SZM涂层)。作为对比,利用机械混合粉末制备了ZrB_2-30%MoSi_2复合涂层(MZM涂层)。借助SEM、XRD和EDS等对涂层的组织结构进行研究,并利用霍尔流速计和松装密度计对团聚粉末的流动性和松装密度进行了测试。此外,对涂层的显微硬度、孔隙率和氧化特性均进行了研究。结果表明:喷雾干燥粉末在1200℃真空烧结1 h后,它的流动性和松装密度分别达到25.8s/50 g和1.12 g/cm~3。与MZM涂层相比,SZM涂层中的MoSi_2分布更加均匀,而且结构更加致密。所以团聚粉末制备的涂层在1500℃表现出更好的抗氧化性能。
The agglomerated ZrB 2 -MoSi 2 composite powders were prepared by spray drying and vacuum sintering. ZrB 2 - 30% MoSi 2 composite coatings (SZM coatings) were prepared by low pressure plasma spraying using these powders as raw materials. In contrast, a ZrB2-30% MoSi2 composite coating (MZM coating) was prepared using a mechanically mixed powder. The microstructure of the coating was studied by means of SEM, XRD and EDS. The flowability and bulk density of the agglomerated powder were measured by Hall flowmeter and bulk density meter. In addition, the microhardness, porosity and oxidation properties of the coatings were studied. The results showed that the fluidity and bulk density of spray-dried powders reached 25.8s / 50g and 1.12g / cm ~ 3, respectively, after being sintered in vacuum at 1200 ℃ for 1 h. Compared with the MZM coating, the distribution of MoSi_2 in the SZM coating is more uniform and the structure is denser. So agglomerated powder prepared coatings exhibit better oxidation resistance at 1500 ° C.