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使用氯化锌(ZnCl2)和氯化铵(NH4Cl)制备了氯化锌铵(AZC,II型,ZnCl2.2NH4Cl)晶体。采用X射线粉末衍射(XRD)技术研究了ZnCl2与NH4Cl摩尔比对晶体类型的影响。用热重分析(TG-DTG)手段研究了样品的热分解行为和非等温动力学特征。TG曲线结果表明AZC(II)热分解由失NH4Cl和ZnCl2热挥发两个步骤完成,TG和DTG曲线表明失NH4Cl包括4个微观过程。非等温分解动力学研究表明,失NH4Cl和ZnCl2热挥发两大步的表观活化能(E)分别为91.25 kJ.mol-1和104.76 kJ.mol-1,指前因子(A)分别为105.94s-1和104.51s-1。研究表明AZC(II)晶体据具有良好热稳定性。晶体生长实验结果表明:合成(非提纯过的)AZC(II)晶体可以用作制备ZnSe晶体的输运剂。
Ammonium zinc chloride (AZC, type II, ZnCl2.2NH4Cl) crystals were prepared using zinc chloride (ZnCl2) and ammonium chloride (NH4Cl). The effect of the molar ratio of ZnCl2 to NH4Cl on the crystal type was investigated by X-ray powder diffraction (XRD). Thermogravimetric analysis (TG-DTG) was used to study the thermal decomposition behavior and non-isothermal kinetics of the samples. The results of TG curve show that the thermal decomposition of AZC (II) is completed in two steps by the thermal volatilization of NH4Cl and ZnCl2. The TG and DTG curves show that the loss of NH4Cl includes four microscopic processes. The results of non-isothermal decomposition kinetics show that the apparent activation energies (E) of NH4Cl and ZnCl2 for the two major steps are 91.25 kJ · mol-1 and 104.76 kJ · mol-1, respectively, and the pre-exponential factors (A) are 105.94 s-1 and 104.51s-1. Studies have shown that AZC (II) crystals have good thermal stability. The experimental results of crystal growth show that the synthesized (non-purified) AZC (II) crystal can be used as transporter for preparing ZnSe crystals.