材料期刊网

PREPARATION OF SILICA MOLECULAR SIEVE MEMBRANE FOR HYDROGEN SEPARATION

B.Q. Jiang , L. Gu , W.L. Zhang , Y.S. Sun and F. Lin Chemical Engineering Department of Nanchang University , Nanchang 330029 , China

金属学报(英文版)

A ceramic tube supported γ alumina silica inorganic composite membrane was made by modifying a ceramic tube supported γ alumina film with a silica sol using sol gel method. The thickness of the silica thin film was 750? and the pore diameter was less than 5?.The prepared silica molecular sieve membrane displayed a high hydrogen permeability and high selectivities of H 2/N 2 and H 2/CO 2 gas mixtures. This composite membrane can be used to separate high purity hydrogen of more than 99 5% from various kinds of industrial waste gas mixtures containing hydrogen.

关键词: silica , null , null , null

STUDY ON PREPARATION OF SUPPORTED ALUMINA MEMBRANE USING SOL GEL METHOD

W.L. Zhang , B.Q. Jiang , Y.S. Sun , F. Lin and L. Gu Chemical Engineering Department of Nanchang University , Nanchang 330029 , China

金属学报(英文版)

A stable colloidal boehmite sol was made with the aluminium iso propoxide made in China and used to prepare the supported γ alumina membrane using sol gel method. The γ alumina thin layer was characterized by SEM, N 2 sorption method and permeation measurement. The γ alumina membrane was prepared with uniform surface, thickness of 3 μm and average diameter of about 5 nm. The permeabilities of the single gases of H 2, N 2, Ar and their separation factors were measured. The experimental data explained a behavior of Knudsen diffusion for the gas transport through the thin membrane.

关键词: boehmite , null , null , null

SIMULATION OF THE MAGNETIZATION REVERSAL PROCESS OF RECTANGLE-SHAPED NiFe FILM ELEMENTS UNDER AN ORTHOGONAL MAGNETIC FIELD

W.L. Zhang , R.J. Tang , W.X. Zhang , B. Peng , H.C. Jiang , H.W. Zhang

金属学报(英文版)

The magnetization reversal process of nano-size rectangle-shaped NiFe film elements with different aspect ratios have been investigated under the orthogonally applied magnetic fields by micromagnetic simulation. Different magnetization reversal modes can appear depending on whether the bias field is applied or not. When there is no bias field, double "C" state is the initial reversal state. However, when there is a bias field, "S" state is the starting mode. The larger the aspect ratio is, the larger the switching field is. But, when the aspect ratio is larger than 3, the increase of the switching field ceases. These results can provide useful information to the application of the patterned NiFe film with rectangular elements.

关键词: NiFe film element , null , null

Parametric Analysis of Tensile Properties of Bimodal Al Alloys by Finite Element Method

W.L. Zhang

材料科学技术（英）

An axisymmetrical unit cell model was used to represent a bimodal Al alloy that was composed of both nano-grained (NG) and coarse-grained (CG) aluminum. Effects of microstructural and materials parameters on tensile properties of bimodal Al alloy were investigated by finite element method (FEM). The parameters analyzed included aspect ratios of CG Al and the unit cell, volume fraction of CG Al (VFCG), and yield strength and strain hardening exponent of CG Al. Aspect ratios of CG Al and the unit cell have no significant influence on tensile stress-strain response of the bimodal Al alloy. This phenomenon derives from the similarity in elastic modulus and coefficient of thermal expansion between CG Al and NG Al. Conversely, tensile properties of bimodal Al alloy are extremely sensitive to VFCG, yield strength and strain hardening exponent of CG Al. Specifically, as VFCG increases, both yield strength and ultimate tensile strength (UTS) of the bimodal Al alloy decreases, while uniform strain of bimodal Al alloy increases. In addition, an increase in yield strength of CG Al results in an increase in both yield stress and UTS of bimodal Al alloy and a decrease in uniform strain of bimodal Al alloy. The lower capability in lowering the increase of stress concentration in NG Al due to a higher yield strength of CG Al causes the lower uniform strain of the bimodal Al alloy. When strain hardening exponent of CG Al increases, 0.2% yield stress, UTS, and uniform strain of the bimodal Al alloy increases. This can be attributed to the increased work-hardening ability of CG Al with a higher strain hardening exponent.

关键词: Nanomaterials , null , null , null , null

试棒的w_0/l_0值对Zn-5%Al合金超塑性m-δ关系的影响

刘勤 , 裔式珙

材料研究学报

在250℃以■=0.025min~(-1)测到的Zn-5%Al 合金的超塑性m-δ曲线均属式。w_0/l_0值加大使m_0,m_L 和δ_F 值增大,但对δ_L 和m_F 值无大影响。试样厚度的加大(由1增大到2mm)仅使δ_L 和δ_F 值增大,考虑w_0/l_0比值的影响,C_3~((m_0-m_L))-(m_L=m_(mas))型C.L.m-δ方程式规划为:或其中,m′_0(W_0/l_0)=m_0,m′_0>m_0;m′_L(w_0/l_0)=m_L,m′_L>m。w_0/l_0=0.15—0.39。当w_O/l_0=1时,缺口效应消失,δ(或δ_F)值为最大。

关键词: Zn-5%Al合金 , mechanics of superplasticity , C.L.m-δequation

压力对L12-Co3(Al,W)化合物弹性性能与电子结构的影响

姚传生 , 陈铮 , 杜秀娟

稀有金属

基于密度泛函理论,采用第一性原理赝势平面波方法计算了不同压力下L12-Co3(Al,W)化合物的弹性性质与电子结构.计算得到零压力下的点阵常数a0与实验值和理论值相符,计算结果表明:在0～45 GPa压力范围内,L12-Co3(Al,W)化合物的弹性常数Cq (CH、C12、C44)与压力满足三阶多项式关系,体模量B、剪切模量G、本征塑性、断裂韧性随压力的增强而增加;通过引入总化学键重叠布局数,定量的计算了金属间化合物的共价键性能,结果显示压力的增加会不断增强L12-Co3(Al,W)化合物中的共价键强度;电荷差分密度分析表明,随着压力的增加,W原子得到电子,A1原子失去电子,Co-Co、Co-W原子间电荷密度明显增强,表现出更强的键合作用.

关键词: 密度泛函理论 , 弹性性能 , 电子结构 , 压力 , L12-Co3(Al,W)化合物

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

Journal of Materials Research

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

关键词: room-temperature

A comparison of the ideal strength between L1(2)Co(3)(Al,W) and Ni(3)Al under tension and shear from first-principles calculations

Applied Physics Letters

The ideal strengths of L1(2)Co(3)(Al,W) in comparison with Ni(3)Al are investigated using the first-principles method. Results for the stress-strain relationships, ideal tensile and shear strengths are presented. The calculated elastic properties agree well with the experimental observations. Co(3)(Al,W) is found to have larger moduli and higher strengths, but less ductile than Ni(3)Al. The electronic structures indicate the directional covalentlike Co-W bonding through d-d hybridization is the origin of excellent mechanical properties of Co(3)(Al,W).

关键词: ab initio calculations;aluminium alloys;cobalt alloys;ductility;elastic moduli;electronic structure;nickel alloys;shear strength;stress-strain relations;tungsten alloys;w-base alloys

316L不锈钢Ni-W-P非晶态化学镀层的耐腐蚀性能

郑志军 , 赵可昕 , 高岩

材料保护

为了弄清316L不锈钢Ni-W-P非晶态化学镀层的耐腐蚀性能,以模拟人工汗液和5.0%H2SO4溶液为腐蚀介质进行了阳极极化试验.结果发现,镀层厚度超过10μm时:(1)Ni-W-P非晶态化学镀层的耐蚀性能与316L不锈钢基本相当;(2)在前48时,Ni-W-P非晶态化学镀层耐汗液的抗变色能力也与316L不锈钢相近,但随着浸泡时间的延长,抗变色能力较316L不锈钢差.

关键词: 化学镀 , Ni-W-P非晶态镀层 , 不锈钢 , 耐腐蚀性能

Jian ZHANG/Langhong Lou

材料科学技术（英）

关键词: