材料期刊网

EXPERIMENTAL RESEARCH ON CrAl MIXED POWDERS BY MECHANICAL ALLOYING

B.S. Qi , C.G. Wang , X. Yaw and Q.F. Peng Schoolof Materials Science and Engineering , Shandong University of Technology , Jinan 250061 , China

金属学报(英文版)

Thechangesof microstructure, phase? structureand microhardnessof Cr Al mixed powders in the processof mechanical? alloying ( MA) have? beeninvestigated by X ray diffractionanalysis , SEM examination and microstructure testing. The results show that the mi crostructure of Cr Al mixed powderssubjected? to mechanicalalloying for96 hoursexhibits super saturated solid solution of Cr andintermetalliccompound η AlCr2 .

关键词: mechanicalalloying( MA) , null , null

g-C3N4及改性g-C3N4的光催化研究进展

冯西平 , 张宏 , 杭祖圣

功能材料与器件学报 doi:10.3969/j.issn.1007-4252.2012.03.007

聚合型半导体材料g-C3N4因其优异的物理性能和光电性能成为当今研究的热门材料.本文从结构分析和理论计算角度讨论了g-C3N4能够作为无金属催化剂的原因,综述了介孔g-C3N4、无机元素掺杂g-C3N4、金属负载g-C3N4、g-C3N4/金属氧化物复合物和有机改性g-C3N4等不同改性g-C3N4的制备和性质,着重分析了他们催化光解水析氢反应的机理、影响因素及研究进展,并阐述了今后的研究方向.

关键词: g-C3N4 , 改性g-C3N4 , 光催化

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

C/G层内混杂复合材料力学性能的实验研究

周光明 , 梁中全 , 赵谦

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2004.05.005

研究了C/G(碳/玻)层内混杂单向复合材料的力学性能,对其拉伸、弯曲、层间剪切、振动阻尼等性能进行了实验研究,并与同样铺层的纯C、G复合材料进行了对比分析.研究表明:C/G层内混杂复合材料可充分利用C、G纤维的各自优点,改善单一材料的模量、强度、断裂韧性、振动阻尼特性等力学性能,模量预测值与实验值较为接近,强度因影响因素较多,二者存在一定的差异,力学性能随C、G体积分数的变化符合混合律,说明了实验方法的合理性.通过C、G相对体积分数的合理设计可满足结构的实际要求.

关键词: 层内混杂 , 复合材料 , 力学性能 , 实验

非等温热重法研究g-C3N4热分解动力学

杭祖圣 , 谈玲华 , 黄玉安 , 应三九 , 徐复铭

功能材料

在半封闭系统中采用直接热解三聚氰胺的方法制备了C3N4,XRD、XPS及元素分析的结果证明了产物是类石墨相C3N4(g-C3N4).用热分析(TG/DTG)研究了g-C3N4的热分解过程.通过迭代法计算了热分解反应活化能Ea,采用积分法结合36种动力学函数来判断g-C3N4热分解的机理函数.计算结果表明,g-C3N4的平均热分解活化能Ea为178.59kJ/mol,可能的动力学函数积分形式是g(a)=[-In(1-a)]4,指前因子A为21.67s-1,对应的热分解动力学方程为:dα/dT=(21.67/β)exp(-178.59×103/RT)×1/4(1-α)[-ln(1-α]-3

关键词: 非等温热重法 , g-G3N4 , 热分解动力学 , 迭代法

Preparation and Photocatalytic Properties of g-C₃N₄/TiO₂ Hybrid Composite

Xifeng Lu Qilong Wang Deliang Cui

材料科学技术（英文）

g-C₃N₄/TiO₂ composite were prepared by hydrolysis of Ti(OC₄Hⁿ ₉ )₄ and the precursors of g-C₃N₄ at room temperature and annealing in nitrogen atmosphere. X-ray diffraction results revealed that all the products were anatase structure. The chemical nature of O, N of the g-C₃N₄/TiO₂ were identified by X-ray photoelectron spectroscopy, presenting N-Ti-O and N-Ti-N doping status of the composite. The g-C₃N₄/TiO₂ composite showed better photocatalytic activity for the UV and visible-light degradation of Rhodamine B.

关键词: Composite materials , Chemical synthesis , X-ray photoelectron spectroscopy (XPS)

g-C3N4光催化性能的研究进展

楚增勇 , 原博 , 颜廷楠

无机材料学报 doi:10.15541/jim20130633

利用光催化剂将太阳能转化为人类可以直接利用的能量，并用其解决地球资源的枯竭和生存环境的恶化是可再生清洁能源研究的一个方向。g-C3N4的独特结构赋予其良好的光催化性能，使之成为光催化领域的研究热点。目前在光催化领域， g-C3N4主要用于催化污染物分解、水解制氢制氧、有机合成及氧气还原。在实际应用中，为进一步提高 g-C3N4的光催化效果，科研工作者开发了多种改进方法，例如物理复合改性、化学掺杂改性、微观结构调整等。本文主要论述了 g-C3N4在光催化领域的应用以及光催化性能的改进方法，简要阐述了光催化和各种改进方法的机理，分析了目前g-C3N4在光催化领域面临的问题和挑战，展望了g-C3N4的应用前景。

关键词: g-C3N4 , 光催化 , 改进方法 , 综述

金属镍掺杂g-C3N4的制备及其光降解性能

郑小刚 , 杜京城 , 李子黎 , 付孝锦 , 由耀辉 , 刘勇

人工晶体学报

采用浸渍法制备不同掺杂量的负载型光催化剂Ni/g-C3N4,并考察其在可见光照下对亚甲基蓝的光降解性能.利用XRD、FT-IR、SEM、TEM、XPS、N2-sorption和ICP-OES等手段表征Ni/g-C3N4样品.研究表明,Ni/g-C3N4催化剂的光催化活性随着金属镍粒子掺杂量的增加而增大,随着亚甲基蓝浓度的增大而减小,其中金属镍掺杂量4.0wt%的样品4-Ni/g-C3N4表现出优异的光催化活性和光降解稳定性.这是由于4-Ni/g-C3N4样品的光降解过程中产生了超氧自由基、羟基自由基和空穴等活性物质,其中超氧自由基起主导作用.金属Ni0离子在光生电子作用下生成Ni2+,O2分子得到电子生成O2·-自由基.这些活性物质的产生有助于光生电子-空穴对的分离和抑制其复合速率,从而实现可见光下高效催化降解亚甲基蓝.

关键词: Ni/g-C3N4 , 掺杂效应 , 亚甲基蓝 , 光降解性能

Cyclic oxidation behavior of glass-ceramic composite coatings on superalloy K38G at 1100 degrees C

Thin Solid Films

The SiO(2)-Al(2)O(3)-ZrO(2)-CaO-ZnO glass-ceramic composite coatings (GC), nanocrystalline NiCoCrAlY coating, and their combinations (bi-layer GC/NiCoCrAlY) were prepared on K38G specimens. The thicknesses of the glass-ceramic coatings and the NiCoCrAlY coatings were about 10 mu m and 20 mu m, respectively. Cyclic oxidation tests were carried out at 1100 degrees C for 120 cycles. Microstructures of the specimens before and after oxidation tests were characterized by SEM, EDS and XRD. The glass-ceramic coatings with or without a NiCoCrAlY intermediate layer improved the isothermal and cyclic oxidation resistance of the Ni-base superalloy K38G at 1100 degrees C, and performed better than the NiCoCrAlY coatings. An alumina layer formed at the glass/metal interfaces of the specimens coated by the glass-ceramic coatings with or without a NiCoCrAlY intermediate layer. The NiCoCrAlY intermediate layer was beneficial to the cyclic oxidation resistance of the glass-ceramic coatings. (C) 2011 Elsevier B.V. All rights reserved.

关键词: Glass-ceramic coating;NiCoCrAlY;Cyclic oxidation;Magnetron sputtering;resistance;microstructure;scales

热压烧结ZrC-SiC-C_g复相陶瓷的组织与力学性能

马宝霞 , 张幸红 , 韩杰才 , 韩文波

稀有金属材料与工程

以ZrC,SiC,石墨为原料,采用热压烧结法制备了ZrC-SiC-C_g三元复相陶瓷,研究了石墨及其用量对所制备陶瓷材料的微观结构和力学性能的影响.结果表明:石墨的加入有效地促进了ZrC-SiC-C_g复相陶瓷的烧结,在添加约10%(体积分数, 下同)石墨时,密度达到最大.同时复相陶瓷表面随着石墨含量的增加,逐渐变得粗糙,即由于石墨与基体的结合较弱使材料表面出现剥落现象.力学性能分析表明,材料的抗弯强度在石墨含量小于10%时并未明显降低,其断裂韧性随着石墨量的增加呈现先增加后降低的趋势,当石墨含量为10%时,断裂韧性出现最大值4.29 MPa·m~(1/2).材料的断裂方式是沿晶和穿晶断裂相结合.

关键词: 热压 , ZrC陶瓷 , 显微结构 , 力学性能 , 石墨