【摘要】 分别采用XRD和光学显微镜对亚微米和纳米TiO2粉体进行表征,通过恒速无压烧结,研究了相变和晶粒尺寸对二氧化钛粉体在不同升温速率下的烧结致密化过程和烧结行为的影响。结果表明,纳米锐钛矿、纳米金红石和亚微米锐钛矿型TiO2致密化开始温度分别是450、750和1 000℃;纳米锐钛矿、纳米金红石和亚微米锐钛矿型TiO2烧结致密化速率最高时所对应的温度分别是880、920和1 025℃。相变的存在可以降低烧结温度,加快烧结速率;粒径小的粉体烧结温度低,且致密度高。更多还原

【Abstract】 The grain size,particle photograph,and phase of sub-micro/nanometer powder of TiO₂ were characterized by XRD and optical microscope.The green compacts were prepared using dry pressing and cold isostatic pressing.The samples were sintered pressureslessly at constant heating rate of 5 ℃/min using automatic high temperature dilatometer.The curves of shrinkage versus temperature were analyzed.The effect of phase transformation and grain size on the densification and sintering behavior were described for sub-micro/nanometer TiO₂ ceramic.The results show that the densification onset temperature for anatase,rutile nanometer TiO₂ and anatase sub-micrometer TiO₂ are 450 ℃,750 ℃ and 1 000 ℃,respectively.The temperature for the maximum densification rates are 880 ℃,920 ℃ and 1 025 ℃,respectively.The phase transformation can accelerate the sintering rate.The fine grain size can reduce the sintering temperature and increase the densification.更多还原