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采用微波烧结法制备了MoSi2和10vol%SiC/MoSi2纳米复合陶瓷。通过SiC预加热体的混合式加热法和合理的保温结构设计,实现了MoSi2低温阶段的快速升温,提高了温度均匀性。密度和力学性能测试结果表明,1 450℃保温60 min烧结工艺下,MoSi2试样的相对密度达到93.4%,断裂韧度4.5 MPa.m1/2,维氏硬度为10.53 GPa,弯曲强度为186 MPa。10vol%SiC/MoSi2试样尽管相对密度下降为90.3%,但各项力学性能均优于MoSi2试样。相比1 650℃热压烧结,微波烧结温度降低了200℃,MoSi2和SiC/MoSi2试样致密性有所下降,但力学性能有较大提高,尤其是MoSi2试样。断口扫描分析表明,微波烧结试样相对热压烧结试样基体晶粒更细,孔隙细小且分布均匀;SiC/MoSi2试样微波烧结的晶粒细化效果不如MoSi2明显。
MoSi2 and 10vol% SiC / MoSi2 nanocomposite ceramics were prepared by microwave sintering. Through the preheating furnace mixed SiC heating method and reasonable design of the insulation structure, the MoSi2 low temperature stage to achieve rapid heating and improve the temperature uniformity. The test results of density and mechanical properties show that the relative density of MoSi2 sample reaches 93.4%, fracture toughness 4.5 MPa.m1 / 2, Vickers hardness 10.53 GPa, flexural strength 186 MPa . Although the relative density of 10vol% SiC / MoSi2 samples decreased to 90.3%, all the mechanical properties were better than MoSi2 samples. Comparing with 1 650 ℃ hot pressing sintering, the sintering temperature of microwave decreases by 200 ℃, the densification of MoSi2 and SiC / MoSi2 samples decreases, but the mechanical properties are greatly improved, especially MoSi2 sample. The fracture scanning analysis shows that the microstructure of the sintered samples is finer and the pores are smaller and more uniform. The grain refinement effect of microwave sintering in SiC / MoSi2 samples is not as obvious as MoSi2.