A.M. Rashidi A. Amadeh
材料科学技术（英文）
In order to achieve the optimum conditions for electroplating nanocrystalline nickel coating from Watts-type bath, the effect of some process parameters namely, bath temperature, current density, and saccharin addition on grain size and texture coefficient (TC= I(200) /I(111) ) of the deposits were investigated by X-ray diffraction
(XRD). The results showed that in a bath containing 5 g/L saccharin, by increasing the bath temperature from 45°C to 55°C, the grain size decreased, whereas further increase of bath temperature resulted in a contrary effect. By increasing the current density from 10 to 75 mA/cm2, both the grain size and TC decreased, while further increase in current density had no significant effect on the grain size. At a given current density, the grain size and TC decreased rapidly by increasing the saccharin content before leveling off at 3 g/L of saccharin. Finally, based on the grain refining the optimum conditions for producing nanocrystalline nickel coating from Watts-type bath have been proposed.
关键词:
Electroplating
,
grain size
,
Nanocrystalline Coating
Acta Chimica Sinica
Passive film formed on 304 stainless steel in 2.5 mol/L H2SO4 solution by using alternating voltage (A. V.) passivation have been investigated by measuring capacitance and photoelectrochemical parameters. The investigation of the effect of measure frequency on the slope of Mott-Schottky curve has been carried out. The photoelectrochemical measurements were consistent with the capacitance measurement. Analysis of the experimental results showed that the passive film formed 304 stainless steel by using A. V. passivation exhibits semiconducting properties. Using the simple model of semiconductor rather than the multi-donor level model can explain satisfactorily the semiconducting behavior of the film formed on 304 stainless steel by using A.V. passivation.
关键词:
A. V. passivation;passive film;semiconducting properties;stainless;steel;model;electrodes
刘勤
,
周善佑
材料研究学报
超塑性m-δ关系曲线可以分为m_L=m_(max)和m_L=m_(min)两大类型。均可由下面的C.L.(刘勤)m-σ方程表示:σ(%)=〔cε~(m-m_0)-1〕×100当σ=σ_0=0时,m=m_0≠0,C=C_0=κ_0/κ_0=1。当σ=σ_1(σ_(11),σ_(12),σ_(13),…,)时,m=m_1(m_(11),m_(12),m_(13),…),C=C_1(C_(11),C_(12),C_(13),…)=κ_1(κ_(11),κ_(12),κ_(13),…)/κ_0,当σ=σ_F时,m=m_F,C=C_F=κ_F/κ_0。对C 值进行“规划”,得到的C_1~(σ_O-σ_L)-(m_L=m_(max)),C_2~(σ_F-σ_L)-(m_L=m_(min)),C_3~(m_0-m_L)-(m_L=m_(max)和C_4~(m_F-m_L)-(m_L=m_(min))四种类型的“规划”方程分别对m_L=m_(max)和m_L=m_(min)型m-σ曲线适用。若m-σ曲线属简单的下降式,C 及其“规划”值均可近似地取1。否则,C-σ关系是应加以研究的问题。m 和k 值对σ值的效应可以分为动态(直接)和静态(间接)两种。最后的σ值是两种效应的综合结果。(注:m 和κ值见基本方程σ=κε~m)
关键词:
张明星
,
材料热处理学报
doi:10.3969/j.issn.1009-6264.2000.02.009
用菊池衍射测定相间位向关系新技术对一种白口铸铁中M7C3型碳化物的晶体学进行了研究.结果表明,在这一材料中至少M7C3型碳化物属于正交晶系,而非一般认为的六方晶系.发现了三种M7C3型碳化物与奥氏体间的位向关系.它们是:(15)C∥(111)A,[101]C∥[10]A和(11)C∥(1)A,[01]C∥[0]A以及(21)C∥(11)A,[112]C∥[0]A.应用最近提出的"Edge-to-edge" Matching理论可对这一结果作出合理的解释.
关键词:
菊池衍射
,
M7C3型碳化物
,
位向关系
材料科学技术（英文）
Investigation has been carried out to find the effects of Nd substitution and Cu addition on the hydrogen storage properties of AB(5)-type alloy with a multicomponent La0.6M0.4Ni4.8Mn0.2 (M=Y, Nd) system. La0.6Y0.4Ni4.8Mn0.2, which was used in an air-conditioning system, showed poor hysteresis and sloping characteristics, which led to a decrease concerning the coefficient of performance of the system. By the substitution of Nd for Y, the hydrogen storage capacity increased, and the plateau pressure decreased a little, but the hydrogen absorption kinetics decreased dramatically. Cu addition can effectively improve the kinetics of hydride formation without changing the hydrogen storage capacity of La0.6Nd0.4Ni4.8Mn0.2. It has been found that La0.6Nd0.4Ni4.8Mn0.2Cu0.1 alloy showed good hydrogen storage characteristics for metal hydride air-conditioning system. The results showed that, for each component of La0.6M0.4Ni4.8Mn0.2, the effective hydrogen storage capacity increased with decrease of the unit cell parameter c/a and the hydrogen absorption plateau pressure increased with decrease of the parameter a.
关键词:
metal hydride;air-conditioning system;sloping;hysteresis;kinetics;chemical-bond;absorption;stability;kinetics;samples;lani5
Fatigue & Fracture of Engineering Materials & Structures
Fatigue data for welded joints subjected to an explosion treatment (ET) were obtained using rotary bending fatigue specimens. The fatigue fracture surfaces were observed by SEM and the dislocation morphologies by TEM. Mechanical properties have been quantitively studied by considering elastic and plastic shock wave characteristics. The test results indicate that the fatigue strength of welded joints subjected to ET is apparently improved due to the action of elastic or plastic stress waves while the ductility of the welded joints, i.e., reduction in area, is greatly increased.
关键词:
Journal of Applied Physics
The structure, magnetic properties, and magnetostriction of arc-melted polycrystalline Sm0.88Dy0.12(Fe1-xMx)(2) (M = Mn, Al, 0 less than or equal to x less than or equal to 0.2) alloys were investigated by microscopy, x-ray diffraction, A. C. initial susceptibility, vibrating sample magnetometry, and standard strain gauge techniques. It was found that the matrix consists almost entirely of the MgCu2-type cubic Laves phase, with a small amount of rare-earth rich phase. The lattice parameter increases approximately linearly with increasing x from 0.740 to 0.750 nm for M = Al. For M = Mn the lattice parameter increases by 0.002 8 nm over the same increase in x. The Curie temperature decreases with increasing x from 670 to 410 and 550 K for M = Al and Mn, respectively. The spontaneous magnetostriction, lambda(111), and polycrystalline magnetostriction, lambda(s), both decrease with increasing Al or Mn substitution for Fe from their initial values of -1452 and -1010 ppm, respectively. Premature disappearance of the splitting of the (440) line and changes in the shape of the magnetostriction curves suggest the substitution of Mn for Fe may produce a change in the anisotropy. No such effects were observed for M = Al. The saturation magnetization, M-S, decreases approximately linearly with increasing substitution of Al or Mn. The changes in the magnetization and magnetostriction can be understood on the basis of a decreasing 3d sublattice moment. (C) 1999 American Institute of Physics. [S0021-8979(99)02409-3].
关键词:
substitution
齐召庆
,
汪宏涛
,
薛明
功能材料
doi:10.3969/j.issn.1001-9731.2016.02.010
采用改进的非接触式混凝土收缩测定仪及标靶,研究了m(M)/m(P)比值(MgO与KH2PO4的质量比)对磷酸镁水泥石自收缩行为的影响,运用八通道微量量热仪、压汞仪、X射线衍射仪、扫描电子显微镜及能谱仪等分析手段,分析了m(M)/m(P)比值对磷酸镁水泥石自收缩的作用机理.结果表明,磷酸镁水泥石的自收缩呈现出3个阶段的特征,即早期的迅速收缩阶段、微膨胀阶段、收缩缓慢发展阶段.随着m(M)/m(P)比值的增大,由于磷酸镁水泥石的水化放热量降低,水泥石内部孔隙率增大,水化产物结晶度降低,水泥石结构疏松,所以,自收缩率减小.
关键词:
磷酸镁水泥
,
自收缩
,
m(M)/m(P)比值
Tesshu Miyahara
材料科学技术（英文）
Magnetic stripe is one of the major applications of magnetic materials. As a key component of the present card technologies magnetic stripes play reliable components for electronic data interchange in worldwide electronic payment systems such as financial cards, transit tickets and phone cards, etc. Magnetic stripes are available in various coercivity materials, widths, lengths, structures and colors with each types of transferable, lamination and pressure sensitive magnetic tapes of Deuton-M. Manufacturing process, structure and characteristics of Deuton-M magnetic tape and sheet are described.
关键词:
