烧结
微晶
材料科学
晶粒生长
微观结构
活化能
表面扩散
等轴晶
阿累尼乌斯方程
粒度
晶界扩散系数
晶格扩散系数
晶界
冶金
复合材料
有效扩散系数
化学
物理化学
吸附
磁共振成像
放射科
医学
作者
Jong-Beom Lee,Jin Young Jeong,Hyowon Lee,Jaesoung Park,Jinman Jang,Ha-Guk Jeong
出处
期刊:Crystals
[Multidisciplinary Digital Publishing Institute]
日期:2023-08-28
卷期号:13 (9): 1311-1311
被引量:6
标识
DOI:10.3390/cryst13091311
摘要
MoO2 micro-powders with a mean pore size of 3.4 nm and specific surface area of 2.5 g/cm3 were compacted by dry pressing, then pressureless sintered at a temperature of 1000–1150 °C for 2 h or for a sintering time of 0.5–12 h at 1050 °C in an N2 atmosphere. Then, their microstructure evolution for morphology, crystallite, and grain growth were investigated. By sintering at a certain temperature and times, the irregular shape of the MoO2 powders transformed into an equiaxed structure, owing to the surface energy, which contributed to faster grain growth at the initial stage of sintering. The crystallite and grain sizes exponentially increased with the sintering time, and the growth exponent, n, was approximately 2.8 and 4, respectively. This indicates that the crystallite growth is governed by dislocation-mediated lattice diffusion, and the grain growth is determined by surface diffusion-controlled pore mobility. The increase in sintering temperature increased both crystallite and grain size, which obeyed the Arrhenius equation, and the activation energies were determined to be 95.65 and 76.95 kJmol−1 for crystallite and grain growths, respectively.
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