B4C-TiB2-SiC复合陶瓷的SPS制备及组织性能研究

针对B₄C陶瓷烧结性能较差、成本较高的技术问题，提出了一种新型的B₄C基复合陶瓷的制备方法. 该方法以B₄C、Ti₃SiC₂及Si的混合粉作为初始粉体，通过放电等离子烧结技术（SPS）制备第二相（TiB₂+SiC）质量分数为30%的B₄C-TiB₂-SiC复合陶瓷，利用SPS特殊的烧结机制以及烧结过程中的原位放热反应，有效提升了B₄C陶瓷的烧结性能，降低了B₄C陶瓷的制造成本. 研究结果表明，在烧结温度为1650 °C，保温时间为5 min，烧结压力为50 MPa的条件下，制备得到了具有较高致密度（98.5%）的B₄C-TiB₂-SiC复合陶瓷. 随着烧结压力的增加，B₄C-TiB₂-SiC复合陶瓷的硬度逐渐增大，断裂韧性不断减小，而复合陶瓷的弯曲强度则呈现出先缓慢增加后迅速增大的变化趋势. 

Microstructure and Mechanical Properties of B4C-TiB2-SiC Ceramics Fabricated by Spark Plasma Sintering

A new preparation method of B₄C-based composite ceramics was proposed to improve sintering performance and decrease preparation cost of B₄C ceramics. Taking B₄C, Ti₃SiC₂, and Si mixtures as raw powders, B₄C-TiB₂-SiC composite ceramics with 30 wt. % (TiB₂+SiC) second phase were fabricated based on spark plasma sintering (SPS) method. Taking advantage of special sintering mechanism of SPS and in situ exothermic reaction during the sintering process, the new method was arranged to improve the sintering property and reduce the preparation cost of B₄C ceramics. The results indicate that composite ceramics with high relative density (98.5%) can be obtained at 1650 °C and 50 MPa for 5 min. With the increasing of sintering pressure, hardness of B₄C-TiB₂-SiC composite ceramics gradually increases, fracture toughness decreases, while flexural strength shows a trend of rise slowly at first and then rise rapidly.