郭宗奇
,
李凤秋
,
彭民
材料研究学报
高Cr_2O_3含量的高纯MgO-Cr_2O_3材料与煤熔渣的接触试验表明,接近MgCr_2O_4化学计量组成,以MgCr_2O_4和Cr_2O_3为相结构的致密材料,抗煤熔渣侵蚀和渗透性俱优。MgCr_2O_4相与煤熔渣接触会慢慢分解,MgO 溶入渣中,Cr_2O_3在渣-耐火材料界面再结晶。
关键词:
镁铬尖晶石
,
molten coal slag
,
decomposition
,
penetration
,
recrystallization
Y.H.Zhu
材料科学技术（英文）
Furnace cooling is a slow cooling process. It is of importance to study structural evolution and its effects on the properties of alloys during the furnace cooling. Decomposition of aluminium rich α phase in a furnace cooled eutectoid Zn-Al based alloy was studied by transmission electron microscopy. Two kinds of precipitates in the α phase were detected in the FCZA22 alloy during ageing at 170℃. One was the hcp transitional α′m phase which appears as directional rods and the round precipitates. The other was the fcc α′′m phase. It was found that the transitional phaseα′m grew in three preferential directions of <110>, <011> and <101>. The orientation relationship between the α phase and transitional phase α′m was determined as , . The non-equilibrium phase decomposition of the α phase is discussed in correlation with the equilibrium phase relationships. (02-2) 'm (fcc)// (02-2) (fcc) , [-111] 'm (fcc)// [-233] (fcc).
The non-equilibrium phase decomposition of the phase is discussed in correlation with the equilibrium phase relationships.
关键词:
Phase decomposition
,
decomposition
,
microstructural
,
evo
Yanqing LIU
材料科学技术（英文）
Inorganic tubular nanostructure MS2 (M=Mo, W, Nb, Ta) were synthesized by two alternative routes. Thermal decomposition method was used for producing fullerence-like MS2 (M=Mo, W) nanotubes on Al2O3 template using ammonium sulfur respectively; NbS2, and TaS2 nanotubes were obtained successfully by reducing corresponding metal trisulfide in a stream of H2 (mixed with N2 in some cases) at elevated temperatures. Detailed experimental procedure, and the characterization of associated results, were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The result reveals that products are composed of high density of MS2 tubular nanostructures with the diameter of 100 nm and length of tens of micrometers. And no mistake, these 1-D (one-dimensional) tubular nanomaterials added quantities and varieties in the growing family of nanotubes of inorganic layered materials.
关键词:
Dichalcogenide
,
thermol
,
decomposition
,
ga
Z. Sun
,
S.L. Zheng
,
Y. Zhang
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.
关键词:
chromite
,
null
,
null
,
null
吕存琴
,
凌开成
,
王贵昌
催化学报
采用广义梯度近似(GGA)的密度泛函理论(DFT)并结合平板模型,研究了CH_4在清洁Pd(111)及O改性的Pd(111)表面发生C-H键断裂的反应历程.优化了裂解过程中反应物、过渡态和产物的几何构型,获得了反应路径上各物种的吸附能及反应的活化能.结果表明,CH_4采用一个H原子指向表面的构型在Pd(111)表而的顶位吸附,CH_3的最稳定的吸附位置为顶位,OH,O和H的最稳定吸附位置均为面心立方.CH_4在清洁Pd(111)表面裂解的活化能为0.97eV,低于它在O原子改性(O没有参与反应)的Pd(111)表面的活化能1.42eV,说明表面氧原子抑制了CH_4中C-H键的断裂.当亚表而O原子和表面O原子(O参与反应)共同存在时,C-H键断裂的活化能为O.72eV,低于只有表层氧存在时的活化能(1.43 eV),说明亚表面的O原子对CH_4分子的活化具有促进作用.CH_4在O原子改性的Pd(111)表面裂解牛成CH_3和H,以及生成CH_3和OH的反应活化能分别为1.42和1.43 eV,说明CH_4在O原子改性的Pd(111)表面发生这两种反应的难易稗度相当.
关键词:
甲烷
,
解离
,
钯
,
氧原子改性
,
密度泛函理论
,
广义梯度近似
,
平板模型
田鸣
,
王晓东
,
朱燕燕
,
王军虎
,
张涛
催化学报
doi:10.3724/SP.J.1088.2010.90703
以共沉淀法制备了LaFe_xMn_yAl_(12-x-y)O_(19)六铝酸盐催化剂,并用X射线衍射、扫描电镜、N_2吸附-脱附、紫外-可见漫反射光谱和穆斯馒尔谱对催化剂进行了表征,考察了催化剂上高浓度N_2O分解反应的性能.结果表明,在所考察的条件下,Mn比Fe更有利于促进六铝酸盐晶相的形成.LaFe_xAl_(12-x)O_(19)(x=0.5,1)中Fe以Fe~(3+)位于六铝酸盐尖晶石结构中的四面体位和镜面层结构中的三角双锥位,其中后者为N_2O分解的主要活性中心.LaMn_yAl_(12-y)O_(19)(y=0.5,1)中Mn优先以Mn~(2+)进入四面体位,然后以Mn~(3+)进入尖晶石结构中的八面体位,并成为N_2O分解的主要活性中心.
关键词:
铁
,
锰
,
六铝酸盐
,
N_2O
,
分解
,
推进剂
,
穆斯堡尔谱
侯鹏
,
周勇敏
,
杨小月
,
陈仕国
硅酸盐通报
利用管式炉,在N2气氛条件下研究了焦炭与分析纯石膏之间的固相还原分解特性.根据石膏分解的固-固反应机理,探索石膏分解反应规律.单因素试验结果表明,在一定范围内,增加C/S摩尔比、升高温度、增加保温时间均能提高石膏的分解率.正交优化试验结果表明,固相还原反应的较优条件为:分解温度1200℃、C/S摩尔比1.3、保温时间50 min;优化条件下,石膏的分解产物为CaO,分解率接近100％.在试验选取的范围内,各因素对石膏分解率影响程度大小的顺序依次为反应温度、停留时间和C/S摩尔比.
关键词:
石膏
,
焦炭
,
固相还原
,
分解
赵珊茸
,
孙大亮
,
郭世义
,
王继扬
,
许效红
人工晶体学报
doi:10.3969/j.issn.1000-985X.2005.03.002
用原子力显微镜实时观测了有机晶体CMTD(CdHg(SCN)4(H6C2OS)2)的表面分解过程,这一分解过程是以表面形貌变化来表征的,并且能反映分解过程中的一些固态反应的物理一化学变化机制.X射线能谱分析(EDAX)表明,相对于新鲜的CMTD晶体,在分解物中Hg低而S高;X射线衍射(XRD)表明分解物为非晶态;红外吸收光谱(IR)表明在CMTD晶体结构中的(H6C2OS)结构基元被分解为H2O和酸;量热分析(DSC)表明CMTD晶体在室温空气中确实有化学反应发生.本文用原子力显微镜实时记录了这一分解过程的形貌变化,发现这种非晶态的分解物的产生过程为:成核一核生长一核分散等.这是首次用原子力显微镜实时观测到这种分解过程.
关键词:
分解
,
固态反应
,
CMTD(CdHg(SCN)4(H6C2OS)2)
,
原子力显微镜
陈宁
,
高祀建
,
霍冀川
,
王海滨
,
朱永昌
硅酸盐通报
以氧化镁、氧化锌、氟化铵为固化剂,采用热分析、XRD和IR分析等手段,研究了不同固化剂对磷酸铬铝粘接剂无定形网络结构、结晶温度、分解温度以及粘接强度的影响,并探讨了其影响机制.结果表明:固化剂能促进磷酸铬铝固化脱水,并使磷酸铬铝析晶温度由925℃降低至800℃左右;分解温度随固化剂不同降低程度不同,以氟化铵降低最多;氧化镁、氧化锌有利于磷氧网络结构的加强,氟化铵则破坏磷氧网络结构中的桥氧,从而导致粘接强度的变化;在网络结构中,固化剂的本质是杂质,是造成体系结晶温度、分解温度降低以及析晶产物不同的主要诱因.
关键词:
磷酸铬铝
,
固化剂
,
网络结构
,
结晶
,
分解
刘爽
,
丛昱
,
张涛
催化学报
doi:10.1016/S1872-2067(11)60402-6
采用溶胶凝胶法制备了Zr掺杂的钴基钙钛矿La(Ba)ZrxCo1-xO3-δ,并将其用于航天推进剂领域的高浓度N2O催化分解反应.发现Zr的引入明显提高了钙钛矿La(Ba)ZrxCo1-xO3-δ的催化活性,尤其是当Zr掺杂量分别为0.05和0.2时,LaZrxCo1-xO3-δ 和BaZrxCo1-xO3-δ催化剂性能较为优异.应用N2物理吸附、X射线衍射、H2 程序升温还原、O2程序升温脱附和氧脉冲吸附技术表征了Zr掺杂对La(Ba)ZrxCo1-xO3-δ催化剂的物化性质的影响.结果表明,Zr掺杂增大了钴基钙钛矿的比表面积,改善了晶格结构,从而提高了钴物种的还原及氧吸附脱附能力,因而催化剂上N2O分解活性增加.
关键词:
钴酸镧
,
钴酸钡
,
锆
,
氧化亚氮
,
分解
