采用自蔓延高温合成/单向加压法(SHS/SAP)在机械轴压下制备ZrC陶瓷.研究压力大小对ZrC陶瓷显微结构与致密度的影响以及位移、负荷曲线的变化规律与SHS反应过程之间的关系.利用XRD与SEM研究产物的物相组成和显微结构,采用排液法测定产物的密度,通过万能试验机平台记录位移、负荷曲线.结果表明:产物基体主要由ZrC相组成.压力的增大加速了排气过程.产物内部的孔洞及ZrC晶粒的尺寸呈变小趋势,致密度呈增大的趋势,而压力为80MPa后致密度增大趋势变化不大,由于在SHS反应结束后的最高温度时压力下降较剧烈,在压力为120MPa时产物的致密度也仅为65.7％.位移、负荷曲线反映了SHS反应结束的时间点及之后产物所处的塑性时间段,这为引入自蔓延高温合成/准热等静压法进一步提高陶瓷致密度的工艺参数提供了依据.
ZrC ceramics were prepared by mechanical axial compression of self-propagating high-temperature synthesis/single action pressing(SHS/SAP).The effects of pressure on microstructure and densification of the products,as well as the relationship between displacement/variation of the load curve and SHS reaction,were studied.The structure and properties of the products were investigated by XRD and SEM.In addition,the density was measured by the drain away liquid method.Meanwhile,universal testing machine was used to record the displacement and load curve alternations.The results indicate that products are mainly composed of ZrC phase,the process of exhaust are accelerated as the increasing of pressure as well,leading to the smaller size of porosity and crystal particles.Density manifested as an increasing pattern by the elevated pressure with no longer change at 80MPa.Due to the strong attenuation of pressure at the peak of temperature,the density of the production is only 65.7％ in 120MPa.The end point of the SHS reaction and the plastic time of the products can bemonitored by displacement and load curve.The results provide evidence for the application of selfpropagating high temperature synthesis/pseudo-hot isostatic pressing to further improve the density of ceramics.
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