李静波
,
张维敬
,
李长荣
,
杜振民
稀有金属
doi:10.3969/j.issn.0258-7076.1998.03.014
本文模拟MOVPE工艺设定热力学条件, 建立了涉及5个相和54个气相物种的In-As-Sb-C-H五元系热力学系统. 采用先进的热力学计算方法, 对该系统进行了热力学分析. 计算结果与实验结果比较发现, 热力学计算能较好地预测系统相关系及半导体相成分.
关键词:
热力学分析
,
MOVPE
,
In
,
As
,
Sb
,
C
,
H
唐煜
,
周春兰
,
贾晓昀
,
王文静
材料导报
SiNx:H薄膜因为具有良好的减反射性质和钝化作用,在晶体硅太阳电池(单晶硅、多晶硅)的研究和生产中得到越来越广泛的应用.介绍了SiNx:H薄膜在硅基太阳电池中的减反射和钝化作用,主要制备方法等研究现状,以及面临的问题和今后的研究趋势.
关键词:
太阳电池
,
SiNx
,
H
,
钝化
,
减反射
谢莎
,
邓爱红
,
王康
,
王玲
,
李悦
,
王勇
,
汪渊
材料研究学报
用磁控溅射方法制备纳米多晶钨膜,采用x射线衍射(XRD),扫描电子显微镜(SEM),弹性反冲探测(ERD)和慢正电子束分析(SPBA)等手段研究了在高能He+和H+依次对其辐照后He相关缺陷对H滞留的影响.结果表明,注He+钨膜在退火后从β型钨向α型钨转变；钨膜中的He含量随着退火温度的提高而减少,在873 K退火加剧钨膜中He原子的释放,且造成钨膜空位型缺陷的增加和结构无序度的提高；钨膜中的H滞留总量随着He滞留总量的减少略有下降.
关键词:
金属材料
,
磁控溅射钨膜
,
慢正电子束分析
,
H
,
He
孙敏
,
李晓刚
,
李劲
金属学报
doi:10.11900/0412.1961.2016.00040
采用慢应变速率拉伸实验研究了一种新型超高强度钢在酸性环境中Cl-和H对应力腐蚀行为的交互作用,并采用SEM观察了试样断口形貌.结果表明,Cl-显著提高Cr12Ni4Mo2Co14钢的应力腐蚀敏感性,实验条件下临界Cl-浓度[Cl-]c为0.15％左右.当Cl-浓度高于[Cl-]c时,Cl-引发严重的点蚀,应力腐蚀裂纹起源于点蚀坑处.Cr12Ni4Mo2Co14钢在含Cl-溶液中的断裂机理可以用“滑移-膜破裂”机制进行解释.充氢后的Cr12Ni4Mo2Co14钢发生氢致开裂,断口上出现二次裂纹.临界充氢电流密度i[H]c为10 mA/cm2(溶液pH=5,充氢时间为30 min).当充氢电流密度大于i[H]c时,Cr12Ni4Mo2Co14的强度损失和塑性损失趋于最大值.溶液中的Cl-浓度和材料中的H有复杂的交互作用,并非简单的加和作用.
关键词:
超高强度钢
,
酸性环境
,
应力腐蚀开裂
,
H
,
Cl-
J
,
H
,
Wang
,
H. Lu and H. Murakawa 1) Shanghai Jiao Tong University
,
Shanghai 200030.China 2) Osaka University
,
Japan
金属学报(英文版)
Local postweld heat treatment (PWHT)is usually performed when it is impractical to heat treat the whole vessel in a furnace, Many factors have an influence on PWHT procedures, such as size of the pipe,heated widths, insulation conditions, heating rates soak temperatures and hold times, material composition etc,. However up to now the influences these factors have on PWHT are not very clearly understood and different criteria for sizing the parameters can be found in different codes. This study provides a direct method to assess the effectiveness of local PWHT.An axisymmetrical model was used based on the thermal-visco-elastic-plastic Finite Element Method with the consideration of creep phenomena. By using this method both temperature and stress distributions can be simulated during whole local PWHT history. The computation results of temperature distributions and the strain histaries during local PWHT are compared with the experiments, and good agreements are obtained, Investigations show that the thermal stresses induced by local PWHT are much affected by creep behavior and the changes of Young's Modulus. The study of stress relief history shows that the stresses decrease quickly in the heating stage, then decrease slowly according to creep law in the hold stage and then studdenly increase when the cooling stage starts. The study shows the possibility that through a series of computations the effects of many factors can be assessed and the optimum parnmeters can be found. Compared with the heated widths based apon some applicable codes, it is found that a heated area of 2.5 on either side of the weld seems more reasonable.
关键词:
postweld heat treatment
,
null
,
null
,
null
FANG Zheng CHEN Xinmin(H.M.Chen) Central South University of Technology
,
Changsha
,
China FANG Zheng
,
Associate Professor
,
Department of Chemistry
,
Central South University of Technology
,
Changsha
,
China
金属学报(英文版)
By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a particular case of it.Some of the variables affecting equilibrium atmosphere when trace oxygen is present and optimum preparation of the gas mixtures to min- imize errors have been discussed.The reliability of some of previous equilibrium experiments under the oxygen potentials controlled by H_2O-H_2 or H_2O-H_2-inerts gas mixtures has also been criticized.
关键词:
gas equilibration method
,
null
,
null
,
null
Applied Physics Letters
ZnCoO:H nanocrystals are weak ferromagnetic at room temperature with a small coercivity and a small remanence, whereas ZnCoO nanocrystals are paramagnetic. The thermal irreversibility of zero-field cooling and field cooling magnetizations of ZnCoO:H nanocrystals corresponds to the existence of superparamagnetism due to the nanosize effect. X-ray photoelectron spectra show the incorporation of Co(2+) ions inside the ZnO lattice without changing the wurtzite structure. Our data suggest that hydrogen can induce ferromagnetism in ZnCoO and that ferromagnetic ZnCoO:H crystals with small particle size can show the superparamagnetism. (C) 2008 American Institute of Physics.
关键词:
magnetic semiconductors;zno;hydrogen;cobalt
