( 1. 湖南冶金职业技术学院 冶金系, 株洲 412000;
2. 中南大学 冶金科学与工程学院, 长沙 410083)
摘 要: 用热重法测定了锌蒸气在不同温度和气氛下的氧化动力学曲线,用扫描电镜观察分析产物的结晶形貌。 结果表明: 氧化动力学遵守直线规律时, 产物的结晶形貌是无定形、 颗粒状和单针状; 氧化动力学曲线为抛物线规律时, 产物的结晶形貌是四针状和多针状。氧化动力学转变规律的原因是锌蒸气中存在超细锌微粒与气态锌原子的动态平衡。 应用动力学理论和上述结果推断了相关条件下的动力学机理函数和动力学常数, 研究了锌微粒的氧化过程并求出了锌原子通过氧化膜层的扩散系数。
关键字: 锌蒸气; 锌微粒; 氧化动力学; 动力学机理函数; 氧化锌结晶形貌
( 1. Department of Metallurgy, Hunan Metallurgical Institute of Professional Technology, Zhuzhou 412000, China;
2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The kinetics of oxidizing zinc vapor in different atmosphere at elevated temperature was determined by thermalgravity apparatus and the morphologies of the oxidation products were examined by scanning electron microscopy. The results show that the products morphologies are amorphous, granular, needle-like when the kinetics advances linearly and the products of tetrapod and multipod-like ZnO appear as the kinetics proceeds parabolically. The change of the oxidation kinetics law is caused by tiny zinc particles formed in zinc vapor. The relative kinetic model functions and kinetics parameters of the title reaction were deduced from kinetic theories and the experimental data. The oxidation mechanism of the tiny zinc particles were investigated and the diffusion coefficient of Zn atoms through the oxidation scale were also deduced.
Key words: zinc vapor; zinc particles; oxidation kinetics; kinetic model functions; ZnO morphologies