摘要
通过热重法 (TG- DTG)、差示扫描量热法 (DSC)、X射线衍射 (XRD)技术研究了固态物质 Zn C2 O4 ·2 H2 O- Ni C2 O4 · 2 H2 O机械混合物 (摩尔比 3∶ 2 )在空气中热分解的过程 .TG- DTG的曲线表明 :其热分解过程 TG曲线中 4个明显的台阶与理论失重相吻合 .XRD结果表明 :样品在 5 0 0℃煅烧生成为较好晶型的 Zn O- Ni O混合物 .用 Kissinger- Akahira- Sunose(KAS)法和 Ozawa法求取 Ea,用热分析动力学三因子求算的比较法判断出可能的机理函数 .Zn C2 O4 和 Ni C2 O4 热分解的活化能分别为 175 .6 9～ 176 .4 8k J/ m ol、2 2 0 .2 8～ 2 0 0 .93k J/ m ol,Zn C2 O4和 Ni C2 O4 分解反应过程可能遵循的机理函数微分形式分别为 f (α) =3(1-α) [- ln(1-α) ]2 /3和 f (α) =2 (1-α)[- ln(1- α) ]1 /2 ;积分形式分别为 g(α) =[- ln(1- α) ]1 /3和 g(α) =[- ln(1- α) ]1 /2 ,都属于随机成核和随后生长型机理函数 (Avram i- Erofeer) ,Am,其调节因子 m=3、2 .
The thermal decomposition processes taking place in the solid state oxalate mixture of ZnC 2O 4·2H 2O-NiC 2O 4·2H 2O (3∶2 mole ratios) have been studied in air using TG-DTG, DSC and XRD techniques. TG-DTG curves showed that, the decomposition proceeds through four well-defined steps with TG curves closely correspond to the theoretical mass loss. XRD showed the product was the well-crystallized mixture of ZnO and NiO when the sample calcined at 500℃ for one hour. The activation energies were calculated through the Ozawa and Kissinger-Akahira-Sunose (KAS) methods, and the possible conversion functions had been estimated through the comparative method. The activation energies for the decomposition of ZnC 2O 4 and NiC 2O 4 were 175.69～ 176.48 kJ/mol and 220.28～200.93 kJ/mol respectively. The possible conversion functions for the decomposition of ZnC 2O 4 and NiC 2O 4 kept to the conversion function of nucleation and growth respectively, A m, m=3、2. The differential forms were respectively rewritten in the form: f(α)=3(1-α)[-ln(1-α)] 2/3 and f(α)=2(1-α)[-ln(1-α)] 1/2, and the integral forms were respectively rewritten in the form: g(α)=[-ln(1-α)] 1/3 and g(α)=[-ln(1-α)] 1/2.
出处
《中南民族大学学报（自然科学版）》
CAS
2004年第4期25-29,共5页
Journal of South-Central University for Nationalities：Natural Science Edition
基金
湖北省自然科学基金重点资助项目 (2 0 0 1ABA0 0 9)
