高温高压下氧化锌纳米晶的晶粒演化动力学

Grain Evolution Dynamics of ZnO Nanocrystals under High Pressure and Temperature

用GS-1B型六面顶压机研究了ZnO纳米晶高温高压下的晶粒演化动力学,用MDI/JADE5X射线衍射仪(Cu靶)和XL30S-FEG场发射扫描电子显微镜对高压样品的相组成、晶粒尺寸及微观形貌进行了表征.实验发现300℃(包括300℃)以下,ZnO纳米材料中晶粒生长速率随着压力的升高先增大后减小,1～3GPa烧结体晶粒尺寸随着压力的升高而增大,4～6GPa烧结体晶粒尺寸随着压力的升高而减小.利用高压下晶粒生长速率方程求出1～3GPa,4～6GPa的激活体积分别为-5.82,9.66cm3/mol.400℃(包括400℃)以上,1～6GPa烧结体的晶粒尺寸随着压力的升高而不断增大.

Grain evolution dynamics of ZnO nano-crystals under high temperature and pressure was studied on a cubic high pressure apparatus. The structure, grain sizes and morphology of the samples were characterized by X-ray diffraction and field emission scanning electron microscopy. It were found that the velocity of grain growth increased at first and then decreased with increasing the pressure below the temperature 300 ℃ （including 300 ℃）. The grain sizes of the samples increased from 1 to 3 GPa and decreased from 4 to 6 GPa. The activation volumes at 300 ℃ from 1 to 3 GPa and from 4 to 6 GPa were calculated using the phenomenological kinetic grain growth equation, which are about --5.82 and 9.66 cm^3/mol, respectively. Above the temperature 400 ℃ （including 400 ℃）, grain sizes of the samples increased with increasing the pressure from 1 to 6 GPa.