Hengzhi FU
,
Xingguo GENG
材料科学技术（英文）
The present paper aims to the characterization of high rate direction solidification on AI-Mn and AI-Cu alloys. It is indicated that the relevant cooling rate of high rate directional solidification is defined within 10(0)～10(3) K/s that is located in the region between near-equilibrium slow growth rate and rapid solidification rate beyond equilibrium condition, and at the meantime there occurred a series of turning effect of interface stability and morphologies. With the increase of growth velocity the interface with planar front evolved to cells and dendrites at the stage of near-equilibrium and with further increase of growth rate they transformed reversely from dendrites to cell structure and then to absolute stability of planar interface. An explanation based on effective constitutional supercooling about the evolution of interface morphologies with the change of growth rate was proposed.
关键词:
J.H. Xie
,
Y.S. Wu
,
J.Q. He
,
X.Z.Yang and R.Z. Zhu (Department of Surface Science & Corrosion Engineering
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)
金属学报(英文版)
This paper investigates the corrosion fatigue (CF) crack initiation behavior of 316L stainless steel in Hank's solution which simulates bodylike fluid. The CF experiments were conducted under the conditions of electrochemically accelerated, free immersion and pre-polarized pitting potential. The results showed that 316L stainless steel was susceptible to pitting corrosion in Hank's solution. Intergranular corrosion occurred obviously at the bottom of pits where the CF cracks initiated by the combined action of alternating stress and corrosive medium for the notch effect of stress concentrated in the grain boundaries.The CF crack propagation is both intergranular and transgranular.
关键词:
: aritificial joints
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null
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null
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null
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null
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null
孙新阁
,
霍立兴
,
张玉凤
腐蚀学报（英文）
采用楔形张开加载恒位移实验研究了X65管线钢在H2S溶液中的应力腐蚀开裂行为，并得出了X65管线钢母材、焊缝和热影响区的临界应力强度因子KISCC分别为55.7093 MPa•m 1/2、33.3189 MPa•m1/2和38.0711 MPa•m1/2；平台处的裂纹扩展速率da/dt分别为3.38×10－9m/s、3.5×10－9 m/s和3.5×10－9m/s.研究结果还表明，焊缝比母材具有更高的应力腐蚀敏感性.
关键词:
管线钢
,
null
,
null
Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences
The electron paramagnetic resonance (EPR) parameters g and the hyperfine structure constants A of CO2+ in ZnX (X = S, Se, Te) and CdTe are studied, using the perturbation formulas of the EPR parameters for a 3d(7) ion in tetrahedra based on two mechanism models. In these formulas, both the contributions from the conventional crystal-field (CF) mechanism and those from the charge-transfer (CT) mechanism are taken into account. According to the investigations, the sign of the g-shift DeltagCT from the CT mechanism is the same as DeltagCF from the CF mechanism, whereas the contributions to the A value from the CF and CT mechanisms have opposite signs. Particularly, the contributions to the EPR parameters from the CT mechanism increase rapidly with increase of the spin-orbit coupling coefficient of the ligand and the covalency effect of the systems, i.e. S2- < Se2- < Te2-.
关键词:
crystal-fields and Spin Hamiltonians;EPR;Co2+;ZnX (X = S, Se, Te);CdTe;atomic screening constants;scf functions;field theory;cr2+ ion;spectra;znse;complexes;crystal;liyf4;znte
蒋秀
,
张艳玲
,
屈定荣
,
刘小辉
腐蚀学报（英文）
doi:10.11903/1002.6495.2013.221
以某酸性气田集输管道工况为研究背景,通过实验模拟研究L360抗硫钢在S沉积环境的3.5％NaCl(质量分数)溶液中的腐蚀行为,结果表明:S的沉积导致L360钢发生了均匀腐蚀和小孔腐蚀;S使L360钢的均匀腐蚀速率增加约50倍;金属的腐蚀行为与S沉积厚度有关,但当S厚度超过临界厚度后,金属的腐蚀速率不再随S的厚度增加而变化;在3.5％NaCl溶液中,含S与不含S条件下L360钢的腐蚀行为明显不同,由于存在明显的腐蚀电位差,S沉积导致了电偶腐蚀的发生.
关键词:
S
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腐蚀
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电偶腐蚀
危兆玲
,
李天保
,
赵君芙
,
梁建
,
马淑芳
,
许并社
材料导报
PbX(X=S,Se)纳米结构材料因其良好的光电性能,在太阳能电池等方面有着较好的应用前景,目前已成为半导体领域的研究热点.概括和总结了几种制备PbX纳米材料的经典和新型方法,其中包括水热法、溶剂热法、化学气相沉积法、中孔材料模板法、熔盐籽晶法、纳米晶的取向附属物法和微波法等,并分析和讨论了各方法的特点及对应产物的特征.
关键词:
PbS
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PbSe
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制备方法
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纳米结构
杨瑞成
,
毕海娟
,
牛绍蕊
,
靳塞特
,
申鹏
材料保护
过去，用电化学和浸泡方法综合研究409L，410S热轧不锈钢的腐蚀性能不够。通过电化学和浸泡试验研究了409L和410S2种热轧不锈钢在80％H2SO4，10％HCl，20％NaOH，6％FeCl3及混合酸（3．2％HCl＋3．8％HNO3）中的耐蚀性能，并与奥氏体不锈钢304作对比。结果表明：3种钢的耐腐蚀能力为304〉409L〉410S。409L比410S耐蚀性好的主要原因：409L含碳量低于410S，碳化物析出极少，且409L基本为单相等轴晶粒，组织比410S均匀；410S中还含30％左右的马氏体，产生大阴极（铁素体）、小阳极（马氏体）的腐蚀微电池，加速了其腐蚀。
关键词:
腐蚀行为
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耐蚀性
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腐蚀溶液
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热轧不锈钢
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极化曲线
N. Afsar Kazerooni
材料科学技术（英文）
A plasma electrolytic nitrocarburising (PEN/C) process was performed on stainless steel 316L to improve the surface properties for using as medical implants. A bath was optimised to reduce the required voltage to 150 volts. Aqueous urea-based solutions with 10% NH4Cl were prepared with slightly different amounts of Na2CO3 to optimise the electrolyte composition. The surface and the cross-section morphologies were studied by scanning electron microscopy. The microstructure and the chemical composition of samples were investigated by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques. The microstructure of the outer layer of the coatings was found to be a complex oxide containing Cr and Fe. The wear properties
of the samples were examined by using a pin on disk wear test with Ringer0s solution and were compared with their wear properties in the ambient atmosphere. The Ringer0s solution acted as a lubricant, reducing friction coe±cient. Hardness and roughness were also studied. The bath with the composition of 10% NH4Cl and 3% Na2CO3 exhibited the best tribological properties. The results showed that the tribological properties of treated samples were improved and the wear mechanism was abrasion of the pin.
关键词:
Plasma electrolytic nitrocarburising
