材料期刊网

SULFIDATION OF Co-15wt%Y ALLOY IN H_2-H_2S MIXTURES AT 600-800℃

NIU Yan , F.GESMUNDO , WU Weitao , ZENG Chaoliu , F.VIANI , (State Key Laboratory for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang.110015 , China)(Istituto di Chimica , Facolta'di Ingegneria , Universita'di Genova , Fiera del Mare , Pad.D , 16129 Genova , Italy)Manuscript received 3 July 1995

金属学报(英文版)

The corrosion properties of a Co-15wt% Y alloy were studied in H_2-H_2S mixtures under a sulfur pressure of 10-3 Pa at 600-800℃ and of 10-2 Pa at 800℃ to examine the effect of Y on the resistance of pure cobalt to sulfur attack at high temperatures.The alloy is nearly single-phase.containing mostly the intermetallic compound Co17Y2 plus a little amount of the solid solution of Y in cobalt.At 600-700℃ and at 800℃ under 10-2 Pa of S2 the alloy forms multi-layered scales consisting of an outer region of pure cobalt sulfide,an intermediate region of a mixture of the sulfides of the two metals and finally an innermost layer of a mixture of yttrium sulfide with metal cobalt.At 800℃ under 10-3Pa of S2,below the dissociation pressure of cobalt sulfide, the alloy forms only a single layer composed of a mixture of metallic cobalt with yttrium sulfide.Pure Y produces only the oxysulfide Y2O2S, as a result of the good stability of this compound and of the presence of some impurities in the gas mixtures used The corrosion kinetics is generally rather complex and irregular except al 800℃under 10-3 Pa of S2.The addition of yttrium always reduces the sulfidation rate of cobalt, even though the formation of a continuous protective external layer of yttrium sulfide is never achieved.The internal sulfidation of Y in Co-15% Y is not associated with a depletion of Y in the alloy.This kind of diffusionless internal attack is typical of alloys with a very small solubility of the most reactive component Y in the base metal A.which restricts severely the Y flux from the alloy towards the alloy-scale interface.

关键词: :cobalt-yttrium alloy , null , null

Cu-Zr/ZrN薄膜体系的电阻率和纳米压入研究

白宣羽 , 汪渊 , 徐可为

稀有金属材料与工程

采用磁控溅射方法在Si(111)基片上沉积Cu-Zr/ZrN薄膜体系作为扩散阻挡层.通过比较Cu-Zr/ZrN薄膜体系和三元非晶(Mo,Ta,W)-Si-N的电阻率,同时比较Cu-Zr/ZrN薄膜体系和Ta,YaN的硬度,说明作为扩散阻挡层的材料的选取,应从整体性能上考虑,而不能仅仅考虑热稳定性等单一指标.

关键词: 非晶 , 电阻率 , 纳米压入 , 硬度

Studies of the g factors and the local structure for Ni3+in LaAl0.9Ni0.1O3, La0.75Y0.25Al0.99Ni0.01O3 and YAl0.9Ni0.1O3

Radiation Effects and Defects in Solids

The electron paramagnetic resonance g factors and the local structure for Ni3+ in LaAl0.9Ni0.1O3 (LAN), La0.75Y0.25Al0.99Ni0.01O3 (LYAN) and YAl0.9Ni0.1O3 (YAN) are theoretically studied from the perturbation formulas of the g factors for a 3d7 ion of low spin (S = 1/2) in tetragonally elongated octahedra. In these formulas, the contributions to the g factors from the tetragonal distortion, characterized by the tetragonal field parameters Ds and Dt are taken into account. According to the calculations, the ligand octahedra around Ni3+ are suggested to suffer 2% relative elongation along the [001] (or C4) axis due to the Jahn-Teller effect.

关键词: defect structures;electron paramagnetic resonance;crystal-fields and;spin Hamiltonians;Ni3+;LaAlO3;LaYAlO3;YAlO3;atomic screening constants;optical-spectra;paramagnetic-resonance;superconducting tapes;lattice-distortions;superposition model;scf;functions;cr3+ ions;crystals;epr

非微扰QCD和核遮蔽效应对K因子的影响

智海素 , 侯召宇

原子核物理评论 doi:10.3969/j.issn.1007-4627.2006.01.002

考虑非微扰量子色动力学物理真空夸克凝聚效应,计算了碳核与碳核在质心系能量分别为630和200 GeV时碰撞Drell-Yan过程的K因子,以及加入核遮蔽因子后非微扰效应对K因子的影响,并把计算结果与没有考虑夸克凝聚非微扰效应的K值进行了对比.结果表明,非微扰效应和核遮蔽效应对K因子影响很小.

关键词: K因子 , Drell-Yan过程 , 夸克凝聚 , 非微扰量子色动力学 , 核遮蔽效应