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
符寒光
,
李定
,
邢建东
稀有金属材料与工程
研究了K-RE变质处理对Fe-V-W-Mo合金机械性能和热物理性能的影响.结果发现,Fe-V-W-Mo合金经K-RE变质处理后,硬度和红硬性略有增加,冲击韧性提高41.82%,达到11.09J/cm2,耐磨性和导热系数提高,热膨胀系数减小.分析了K-RE改善Fe-V-W-Mo合金性能的机理,并制造了K-RE变质Fe-V-W-Mo合金轧辊,在热轧生产中使用获得了良好的效果.
关键词:
K-RE变质处理
,
Fe-V-W-Mo合金
,
机械性能
,
物理性能
,
轧辊
符寒光
,
邢建东
,
李言祥
稀有金属材料与工程
用K-RE对Fe-5%V-5%W-5%Mo-5%Cr-3%Nb-2%Co-2%C合金变质处理,使凝固组织发生了明显的变化,不仅碳化物和基体组织明显细化,还出现共晶碳化物断网现象,产生了较多的小块状和颗粒状碳化物.经K-RE变质处理Fe-V-W-Mo合金加热温度950℃时,碳化物断网明显,加热温度1 000℃时,多数碳化物已断网,并出现了数量较多的颗粒状碳化物,加热温度1 050℃时,碳化物网状组织全部消失,大部分碳化物变成了球状组织.
关键词:
变质处理
,
K-RE
,
Fe-V-W-Mo合金
,
共晶碳化物
,
团球化
Physica Status Solidi B-Basic Research
The high-order perturbation formulas of zero-field splitting D and gyromagnetic factors g(parallel to) and g(perpendicular to) for 3d(3) ions in tetragonal symmetry are established by using a two-spin-orbit(SO)-parameter model where the contributions to these EPR parameters from both the SO coupling of the central 3d(3) ions and that of the ligands are considered. From these formulas, the local structural parameters for the tetragonal V2+-V-M centers in MCl:V2+ (M = Na, K, Rb) crystals are estimated from the EPR data. The results are compared with those obtained from the conventional one-SO-parameter model where only the contribution of the SO coupling of central 3d(3) ions is included. The reasonableness of the results based on the two-SO-parameter model is discussed.
关键词:
ions
Journal of Alloys and Compounds
Phase relations in the Fe-rich region of the Nd-Fe-V system at 1323 K have been investigated by means of powder X-ray diffraction. In the investigated composition region, two ternary phases: Nd(Fe1-xVx)(12) (x=0.125-0.167) and Nd-3(Fe1-xVx)(29) (x=0.066-0.095), and one pseudobinary phase: Nd-2(Fe1-xVx)(17) (x=0.000-0.067) are identified. The dependence of the cell parameters on x in Nd(Fe1-xVx)(12), Nd-3(Fe1-xVx)(29) and Nd-2(Fe1-xVx)(17) are presented. Also given are the dependences of the Curie temperatures on the V content (x) in Nd(Fe1-xVx)(12) and Nd-2(Fe1-xVx)(17) The preferential occupation of V in Nd(Fe1-xVx)(12) and Nd-2 (Fe1-xVx)(17) is deduced from the slope of a and c with V content. (C) 1999 Published by Elsevier Science S.A.
关键词:
ternary neodymium compounds;Nd-Fe-V compounds;crystal structure;solid;solubilities;phase equilibria;neutron-diffraction;magnetic-properties
胡标
,
尹明
,
王庆平
,
闵凡飞
,
杜勇
兵器材料科学与工程
基于文献报道的实验数据,采用相图计算(CALPHAD:CALculation of PHAse Diagrams)方法对V-M(M=Li,Na,K,Sc,Ag)5个二元系进行相图热力学研究.通过热力学优化计算获得了一套描述液相、(V)、(Li)、(Na)、(K)、(αSc)、(βSc)和(Ag)相的热力学参数.V-Li、V-Na和V-K体系中的气相视为由组元V、Li、Li2、Na、Na2、K和K2混合的理想气体.与实验相图数据对比表明,获得的热力学参数能够准确地描述实验相平衡数据.
关键词:
V-M(M=Li,Na,K,Sc,Ag)
,
CALPHAD方法
,
相图
,
热力学模型
孔祥建
,
荆海
,
黄霞
,
廖燕平
,
刘金娥
液晶与显示
doi:10.3969/j.issn.1007-2780.2007.05.017
提出了一种更为准确的测量向列相液晶展曲、弯曲弹性常数的C-V方法.以正性液晶材料为例,当沿面排列的液晶分子预倾角不为零时,阈值电压值不易确定, k11的确定必定存在误差,而以前报道并未考虑到此问题.文章针对此问题给出了在强锚定条件下,预倾角不为零时C-V的关系式,并提出了通过曲线拟合来同时确定弹性常数k11、k33的方法.此方法对弹性常数的测量更为准确,液晶盒的制作要求降低,且测试简单、易操作.
关键词:
向列相液晶
,
电容-电压
,
弹性常数
,
预倾角
,
曲线拟合
