PHASE EQUILIBRIUM OF SBCL_3-HCL-H_2O SYSTEM

ＰＨＡＳＥＥＱＵＩＬＩＢＲＩＵＭＯＦＳｂＣｌ３－ＨＣｌ－Ｈ２ＯＳＹＳＴＥＭＤｕａｎ，Ｘｕｅｃｈｅｎ；Ｚｈａｎｇ，Ｄｕｏｍｏ；Ｚｈａｏ，Ｔｉａｎｃｈｏｎｇ（ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｃｈａｎｇｓｈａ４１００８...     

Thermodynamic properties of 1-nutyl-3-methylimidazolium chloride (C<Subscript>4</Subscript>mim[Cl]) ionic liquid

Thermodynamic properties of 1-butyl-3-methylimidazolium chloride (C₄mim[Cl]) ionic liquid were determined using thermogravimetric (TG) differential thermal analysis (DTA). A new method called DTA mass-difference baseline, was used to measure the heat capacity and enthalpy change of phase transformation of ionic liquid from DTA curves. Based on this, the changes in standard enthalpy, entropy, and Gibbs energy were determined. The results show that standard enthalpy and entropy changes of C₄mim[Cl] increase nonlinearly with increasing temperature, while the standard Gibbs energy change decreases nonlinearly with increasing temperature within the temperature range studied (298–453 K). The standard enthalpy of melting and enthalpy of vaporization were determined to be 0.93 and 11.07 kJ/mol, respectively.     

纳米亚铬酸镍的制备及其催化特性

以硝酸铬和硝酸镍为原料,采用溶胶-凝胶法制备了纳米Ni Cr2O4,并用XRD和SEM对纳米亚铬酸镍(nano-NiCr_2O_4)的微观结构进行了表征。同时,采用TG-DTG研究了nano-NiCr_2O_4对六硝基六氮杂异伍兹烷(CL-20)和高氯酸铵(AP)热分解的催化作用,用Kissinger法、Ozawa法计算了非等温动力学参数,发现nano-NiCr_2O_4使CL-20和AP的热分解峰温降低,热分解表观活化能减小。     

Thermal decomposition kinetics and lifetime of the complex of Tb2（BA）6（PHEN）2

The thermal behavior of Tb2(BA)6(PHEN)2 (BA: benzoate, and PHEN: 1,10-phenanthroline) in a static air atmospbere was investigated by TG-DTG, SEM and IR techniques. By the kinetic method of processing thermal analysis data put forward by Malek et al., it is defined that the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energy E for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS^≠ is -84.72 J/mol, the enthalpy of activation ΔH^≠ is 94.26 kJ/mol, the free energy of activation ΔG^≠ is 144.77 kJ/mol and the pre-exponential factor lnA is 20.93.The lifetime equation at mass-loss of 10% was deduced as lnτ = -29.0312 19760.83/T by isothermal thermogravimetric analysis.     

耐酸非贵金属Ti／MO2阳极SnO2＋Sb2O4中间层研究

采用热分解法制备了非贵金属Sn02＋Sb204中间层Ti基MO2活性层电极，利用SEM，XRD和XPS方法对中间层进行了表征。测定了Ti／SnO2＋Sb2Od／MnO2和Ti／SnO2＋Sb2O4／PbO2电极在硫酸溶液中的析氧极化曲线，二者起始析氧过电位均比贵金属小；考察了在高电流密度（4A／cm^2）下的加速寿命，二者依次分别达到18h和86h。实验表明，SnO2＋Sb2O4是一种具有良好导电性和结合力的耐酸Ti基MO2电极中间层材料。     

Kinetics of Thermal Decomposition for Complex [Zn(C_(16)H_(18)FN_3O_3)_2(NO_3)_2]·2H_2O

1 ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｒｅｃｅｎｔｙｅａｒｓ ,ｔｈｅｉｎｔｅｒａｃｔｉｏｎｂｅｔｗｅｅｎｎｏｒｆｌｏｘａｃｉｎａｎｄｃｅｒｔａｉｎｍｅｔａｌｌｉｃｉｏｎｓｈａｓｂｅｅｎｖａｌｕｅｄｗｉｄｅｌｙ[1～ 4].Ｂｕｔｔｈｅｎｏｎ ｉｓｏｔｈｅｒｍａｌｋｉｎｅｔｉｃｓｏｆ[Ｚｎ(ＮＦＡ) 2 (ＮＯ3) 2 ]·2Ｈ2 Ｏｔｈｅｒｍａｌｄｅｃｏｍ ｐｏｓｉｔｉｏｎｈａｓｒａｒｅｌｙｂｅｅｎｓｔｕｄｉｅｄ .Ｉｎｔｈｉｓｐａｐｅｒ ,ｗｅｄｉｓｃｕｓｓｅｄｉｔｓｔｈｅｒｍａｌｄｅｃｏｍｐｏｓｉ ｔｉｏｎｂｅｈａｖｉｏｒｂｙ…     

Supermolecular template route to fabrication of well crystallized hollow antimony microspheres

1 Introduction The preparation of hollow spheres in the nanometer to micrometer scale is of particular interest due to their specific structure and wide applications in artificial cells[1], light-mass structured materials[2,3], catalysts[4], controlled re…     

有机大阳离子与HnXW12O40·nH2O（X=B，Si，P）多金属氧酸盐的合成及热行为

合成了3种新的多金属氧酸盐(CTMA)5BW12O40·8H2O,(CTMA)4SiW12O40·3H2O,(CTMA)3PW12O40·2H2O,利用元素分析、IR光谱和TG-DTA技术对其进行了表征.IR光谱表明这些化合物不仅含有Keggin型结构,而且存在有机大阳离子的特征吸收峰;TG-DTA曲线显示它们的热行为是一个多步分解过程,首先这些化合物在大约269℃以下脱去水分子,然后它们的无水多金属氧酸盐经历了两步或3步的分解过程,分别脱去CTMA分子及其碎片,并伴随Keggin型结构的塌陷.通过XRD和IR光谱确证其最终分解产物是一个含有WO3与B2O3,SiO2或P2O5的混合物.同时还提出了这些化合物可能的热分解过程.     

Semiconducting of nanocrystalline tin oxide and its influence factors

1 INTRODUCTIONSnO2has non-stoichiometric structure and itsconductivity critically originates from oxygen va-cancies initself ,but the content of oxygen vacan-cies in materials is usually difficult to control .Doped SnO2with Sb, Mo and Fis often availablefor applications to various areas such as displays ,electrochromic windows , gas sensors , catalysts ,rechargeable Li batteries and optical electronic de-vices[1 7].Specially Sb is the best dopant ,becauseSnO2is of the preferable conduc…     

Removal of cobalt from zinc sulphate solution using rude antimony trioxide as additive

1　ＩＮＴＲＯＤＵＣＴＩＯＮＲｏａｓｔ ｌｅａｃｈ ｐｕｒｉｆｉｃａｔｉｏｎ ｅｌｅｃｔｒｏｗｉｎｎｉｎｇｐｒｏｃｅｓｓｉｓｔｈｅｍｏｓｔｃｏｍｍｏｎｍｅｔｈｏｄｆｏｒｚｉｎｃｐｒｏｄｕｃｔｉｏｎｉｎｔｈｅｗｏｒｌｄ[1 ] .Ｔｈｅｒｅｍｏｖａｌｏｆｃｏｂａｌｔｆｒｏｍｚｉｎｃｓｕｌｐｈａｔｅｓｏｌｕ ｔｉｏｎｂｙｃｅｍｅｎｔａｔｉｏｎｈａｓｂｅｅｎｔｈｅｆｏｃｕｓｏｆｒｅｓｅａｒｃｈｆｏｒｍｏｒｅｔｈａｎ 2 0ｙｅａｒｓｉｎｔｈｅｈｙｄｒｏｍｅｔａｌｌｕｒｇｙｏｆｚｉｎｃ[1 ,2 ] .Ｔｈｅｐｒｅｓｅｎｃｅｏ…     

Ti/IrO2+MnO2电极在酸性溶液中的析氧反应动力学研究

采用涂覆热分解法制备Ti/IrO₂+MnO₂复合电极,利用慢速线性电位扫描伏安法测试Ti/IrO₂+MnO₂电极的准稳态极化曲线并深入地研究析氧反应动力学,得到了相关动力学参数、反应历程及速度控制步骤。通过分析经欧姆电压降修正的Tafel曲线,较好地解释了Tafel直线区域的双斜率现象,基于此提出析氧反应动力学方程并进行数学推导,较好地符合实验结果。实验所得氢离子反应级数约为零,低电位区与高电位区的表观活化能分别为30.31和13.64 kJ/mol,进一步证明该数学模型的正确性。     

非等温条件下机械活化Ag2O-石墨混合物Arrhenius参数的测定

采用DSC和TGA及模型拟合Malek法和无模型改进Vyazovkin等转化率法研究机械化学还原Ag2O和石墨混合物的非等温动力学。为了测定动力学参数,选取研磨活化2 h和4 h的及未球磨的Ag2O-石墨混合物为样品。基于Vyazovkin法计算得到的活化能最大值和最小值之间的差比平均活化能小20%-30%（（99.38±2.36）k J/mol）,Ag2O机械活化2 h的热分解是一个多步过程,机械活化4 h的热分解是一个单步过程（平均活化能为（93.68±2.26）k J/mol）。动力学模型表明,未球磨的Ag2O-石墨混合物的热分解过程比其他的复杂。Ag2O-石墨混合物的自动催化趋势比其他的低。     

Sb掺杂量对ATO纳米颗粒结构及激光吸收性能的影响(英文)

以SnCl4·5H2O和SbCl3为原料,采用共沉淀法制备不同Sb掺杂量的氧化锡锑(ATO)纳米粉末。分别采用XRD、FESEM、紫外可见分光光度计和激光器对晶体结构、形貌、激光反射率进行表征,研究Sb掺杂量对ATO纳米颗粒的结构、晶粒尺寸和激光反射性能的影响。结果表明:共沉淀法制备的ATO纳米颗粒为四方相金红石结构,粒径大小约为几十纳米;随着Sb掺杂量的增加,ATO的晶粒尺寸减小,晶胞体积则逐渐增大;与未掺杂的SnO2粉末相比,Sb掺杂后的ATO粉末在1.06μm激光波长处的反射率明显低于未掺杂的SnO2的反射率;随着Sb掺杂量的增加,反射率值呈先减小后增大的趋势,在Sb掺杂量为20%时,ATO粉末在1.06μm激光波长处的反射率低于0.02%,激光隐身性能最佳。     

Stability constants of Sb5+ with Cl− and thermodynamics of Sb−S−Cl−H2O system involving complex behavior of Sb with Cl

The stability constants of Sb⁵⁺ with Cl⁻ as well as thermodynamics of the Sb–S–Cl–H₂O system were calculated. The stability constants of Sb⁵⁺ with Cl⁻ were obtained by theoretical calculations of the absorbance of a Sb⁵⁺-containing solution at different Cl⁻ concentrations, which was detected by spectrophotometric analysis at certain wavelengths of light (380 nm). The logarithmic values versus 10 of stability constants of Sb⁵⁺ with Cl⁻ were 1.795, 3.150, 4.191, 4.955, 5.427 and 5.511, respectively, and partly filled the data gaps in the hydrometallurgy of antimony. The presence and distribution of pentavalent antimony compounds under different conditions were analyzed based on equilibrium calculations. Thermodynamic equilibrium calculations were performed for Sb–S–Cl–H₂O system, which included the complex behavior of Sb with Cl, and the equilibrium equations of related reactions in this system were integrated into the potential–pH diagram.     

Thermodynamic analysis of separating lead and antimony in chloride system

In chloride system, thermodynamic analysis is a useful guide to separate lead and antimony as well as to understand the separation mechanism. An efficient and feasible way for separating lead and antimony was discussed. The relationships of [Pb2+][Cl-]2-lg[Cl]T and E-lg[Cl]T in Pb-Sb-Cl-H2O system were studied, and the solubilities of lead chloride at different antimony concentrations were calculated based on principle of simultaneous equilibrium. The results show that insoluble salt PbCl2 will only exist stably in a certain concentration range of chlorine ion. This concentration range of chlorine ion expands a little with increasing the concentration of antimony in the system while narrows as the system acidity increases. The solubility of Pb2+ in solution decreases with increasing the concentration of antimony in the system, whereas increases with increasing the concentration of total chlorine. The concentration range of total chlorine causing lead solubility less than 0.005 mol/L increases monotonically.     

Characterization and kinetic modeling of secondary phases in squeeze cast Al alloy A380 by DSC thermal analysis

Thermal analyses on squeeze cast aluminum alloy A380(SC A380) solidified under 90MPa were carried out to study the microstructure development of the alloy, in which a differential scanning calorimeter(DSC) was employed. During the DSC runs, heating and cooling rates of 1, 3, 10, and 20 °C·min~(-1) were applied to investigate the heating and cooling effects on dissolution of secondary eutectic phases and microstructure evolution. Various reactions corresponding to troughs and peaks of the DSC curves were identified as corresponding to phase transformations taking place during dissolution or precipitation suggested by the principles of thermodynamics and kinetics. The comparison of the identified characteristic temperatures in the measured heating and cooling curves are generally in good agreement with the computed equilibrium temperatures. The microstructure analyses by scanning electron microscopy(SEM) with energy dispersive X-ray spectroscopy(EDS) indicate that the distribution and morphology of secondary phases present in the microstructure of the annealed sample are similar to the as-cast A380, i.e., strip β(Si), buck bone like or dot distributed θ(Al_2Cu), β(Al_5Fe Si) and Al_(15)(FeMn)_3Si_2. Two kinetic methods are employed to calculate the activation energies of the three common troughs and three common peaks in DSC curves of SC A380. The activation energies of the identified reaction θ_(CuAl_2) = α(Al)+β(Si) is 188.7 and 187.1 k J?mol~(-1) when the activation energies of reaction α(Al)+β(Si)→θCu Al_2 is~(-1)22.7 and~(-1)21.8 k J?mol~(-1), by the Kissinger and Starink methods, respectively.     

氯化物水溶液体系三价铬电沉积机理研究

采用循环伏安、恒电流阶跃和稳态极化等电化学研究方法和紫外分光度法,研究了Cr3+电沉积机理,结果表明其沉积过程分2步进行。计算得出Cr3+2步放电的表观活化能为34.9 kJ/mol和19.77 kJ/mol,表明Cr3+还原过程受电化学反应控制;初步拟定了甘氨酸作配体氯化物水溶液体系三价铬还原机理。     

锑对AZ91D镁合金微观组织的影响

研究了锑对AZ91D镁合金微观组织的影响。在AZ91D镁合金熔炼过程中加入三氧化二锑引入锑元素,用光学显微镜对加锑前后合金显微组织及其变化情况进行研究,发现锑的加入可使AZ91D镁合金的组织发生明显变化,β-Mg17Al12脆性相由连续网状分布逐渐变为离散状。同时利用扫描电镜、能谱仪和透射电镜分析了锑在合金中的存在形式。结果表明,锑在AZ91D镁合金中主要以两种形式存在:固溶在α-Mg、β相中;形成新相Mg3Sb2。锑在镁合金中生成的新相Mg3Sb2既作为异质形核核心细化组织,又会聚集在固液界面前沿抑制晶体的长大,从而对镁合金起到细化晶粒的作用。     

Influence of indium addition on structure, mechanical, thermal and electrical properties of tin–antimony based metallic alloys quenched from melt

The melt-spinning processes of binary Sn–10 wt.% Sb and ternary Sn–10 wt.% Sb–In were analyzed using X-ray diffractometer and differential thermal analysis (DTA). The results showed that supersaturated solid solution and new intermetallic compound In₃Sn were produced during melt-spinning technique not found under equilibrium conditions. It is also found that a small amount of In addition significantly lowers the melting point of the Sn–10 wt.% Sb alloy and reduce the crystal size to ≈60 nm. Also, tin–antimony solder doped with In exhibits good mechanical properties, Vickers hardness and mechanical strength due to refined microstructure. This work was performed to study the influence of rapid solidification and indium addition on structure and properties of tin–antimony based alloys.     

KINETIC STUDY OF SPINEL LiMn2O4 SYNTHESIZED BY SOLID REACTION WITH SOFT-CHEMICAL METHOD

1. IntroductionLithium -ion battery is the third generation rechargeable battery follow ing nickel-cadm ium batteryand m etal-hydrogen nickelbattery. Itisapplied in m any fields, such as portable notebook com puter,electro-m obile, space airship and m edi…