M.H. Li
,
G.H. Yu
,
F.W. Zhu
金属学报(英文版)
The exchange bias field of NiFe/FeMn films with Ta/ Cu buffer was proved to be lowerthan that of the films with Ta buffer. The crystallographic texture, surface roughnessand elements distribution were examined in these two sets of samples, and there isno apparent difference for the texture and roughness. However, the segregation ofCu atoms above NiFe surface in the maltilayer of Ta/Cu/NiFe has been observed byusing the angle-resolved X-ray photoelectron spectroscopy (XPS). The decrease of theexchange bias field for NiFe/FeMn films with Ta/ Cu buffer layers is mainly causedby the Cu atoms segregation at the interface between NiFe and FeMn.
关键词:
NiFe/FeMn
,
null
,
null
,
null
,
null
熊进辉
,
黄继华
,
薛行雁
,
张华
,
赵兴科
,
林国标
航空材料学报
doi:10.3969/j.issn.1005-5053.2009.6.010
本文利用AgCuTi-W复合钎料作中间层,在适当的工艺参数下真空钎焊C_f/SiC复合材料与Ti合金,利用SEM,EDS,XRD分析接头微观组织结构,利用剪切试验检测接头力学性能.研究结果表明:钎焊时,复合钎料中的Ti借助Cu-Ti液相与C_f/SiC复合材料反应,在C_f/SiC复合材料与连接层界面形成Ti3SiC2,Ti3Si和少量TiC化合物的混合反应层.复合钎料中的Cu与Ti合金中的Ti发生互扩散,在连接层与Ti合金界面形成不同成分的Cu-Ti化合物过渡层.钎焊后,形成W颗粒强化的致密复合连接层,W颗粒主要分布在Cu-Ti相中.W的加入缓解了接头的残余热应力,C_f/SiC/AgCuTi-W/TC4接头剪切强度明显高于C_f/SiC/AgCuTi/TC4接头.
关键词:
C_f/SiC
,
Ti合金
,
钎焊
,
AgCuTi-W
汪华剑
,
方庆艳
,
姚斌
,
雷霖
,
段学农
,
赵云辉
,
汪毅冈
,
周怀春
工程热物理学报
本文通过数值模拟和在实际锅炉上的试验,研究了310 MW Foster Wheeler技术w型火焰锅炉F层二次风下倾15°对炉内燃烧过程的影响.通过对模拟和试验的分析表明,F层二次风下倾后对炉内燃烧的影响主要表现在火焰行程延长,煤粉停留时间增加,还原区扩大,一次风与二次风的混合推迟等方面.试验和模拟结果都表明,F层二次风下倾后锅炉的火焰中心下降,飞灰含碳量降低,锅炉效率提高且NOx排放明显减少.
关键词:
W型火焰锅炉
,
F层二次风下倾
,
煤粉燃烧
,
提高效率
,
降低NOx
HUANG Huimin CHEN Xinmin Central South University of Technology
,
Changsha
,
China HUANG Huimin Associate Professor
,
Department of Chemistry
,
Central South University of Technology
,
Changsha
,
China
金属学报(英文版)
The nature of the oxygen contained in β-W was investigated with DSC,X-ray analysis on quenched samples and Auger spectroscope.It was shown that the oxygen contained in nonpyrophoric β-W consists of the reversibly chemisorbed oxygen and the interstitial oxygen which could form an interstitial solid solution with β-W.It seems better to consider β-W to be a metastable phase of tungsten with the interstitial oxygen as stabilizer.
关键词:
tungsten
,
null
,
null
,
null
Physical Review B
The effect of W on the structural stability of TiAl intermetallic systems and the site preference of W in B2 and L1(0) TiAl were studied based on first-principles calculations. It was found find that about 15 at. % W addition, in good agreement with experiment, is required to stabilize the B2 structure in a TiAl base alloy. W was predicted to occupy Al sites in the B2 phase, but Ti sites in the L1(0) phase. The B2-stabilizing effect of W and its site preference can be explained perfectly on the basis of the pseudogap effect and the strong covalent W-Ti bonding. The strong W-Ti bonding pairs are maximized when W occupies Al sites in B2 TiAl. But when W occupies Al sites in L1(0) TiAl, the W-Ti bonding is weakened by the existence of Al in the alternating (002) plane, which can, however, strengthen the in-plane W-Ti bonding when W occupies Ti sites.
关键词:
gamma-titanium aluminides;electronic-structure;microstructure;deformation;systems;alloys
阳建红
,
董进辉
,
李海斌
,
石强
,
郭明映
复合材料学报
在60℃、80℃相对湿度90%环境条件下对F-12纤维进行了湿热老化实验,研究了长时间老化时纤维吸湿规律.通过ATR-FTIR光谱分析了湿热老化后水对F-12纤维化学结构的影响以及水在纤维中可能存在的方式,探讨了吸湿机制,实验研究了纤维单丝拉伸强度的变化,并采用SEM观察了纤维表面及拉伸断口形貌.结果表明:F-12纤维长时间的吸湿属于2阶段吸湿,吸湿初期符合Fick第二定律,后期偏离,吸湿2500 h后仍没达到平衡;水分子对F-12纤维的化学结构没有造成明显的破坏,老化2500 h后F-12纤维表面变得粗糙,出现了一些沟槽,老化后期断口呈现出脆性与原纤化复合的特征;拉伸断裂强度并非持续减小,而是在起伏波动中减小.
关键词:
F-12纤维
,
吸湿规律
,
ATR-FTIR
,
SEM
,
吸湿机制
,
拉伸强度
杨武
,
陈淼
,
康经武
,
欧庆瑜
,
康敬万
,
高锦章
冶金分析
doi:10.3969/j.issn.1000-7571.1999.05.013
对f-f跃迁光谱在分析化学中的应用进展进行了简要的总结,详细地介绍了根据超灵敏跃迁强度变化规律测定溶液中镧系配合物的组成、形成常数及测定混合稀土中单一稀土的原理和方法.
关键词:
f-f跃迁光谱
,
镧系元素配合物
,
组成测定
,
形成常数
,
综述
Journal of Applied Physics
The ternary intermetallic compound Gd3Fe28.2W0.8 with a Nd3Fe29-xTix-type structure was synthesized with W as a stabilizing element, and its crystal structure and magnetic properties were investigated by means of x-ray powder diffraction and magnetic measurements. The space group of Gd3Fe28.2W0.8 is Angstrom 2/m with lattice parameters a=10.5812 Angstrom, b = 8.5338 Angstrom, c = 9.6986 Angstrom, and beta = 96.86 degrees. Rietveld refinement of the crystal structure reveals that W atoms occupy exclusively three crystallographic positions (4g, 4i(3), 4i(4)) with only one neighboring Gd atom. The preferential occupation of W atoms can be understood in terms of the site volume and enthalpy of mixing. The compound exhibits a planar magnetocrystalline anisotropy perpendicular to the [102] direction. The Curie temperature T-c, saturation moment M-s, and anisotropy field H-A are 502 K, 38.6 mu(B)/f.u., and 7.5 T, respectively. (C) 2000 American Institute of Physics. [S0021-8979(00)07520-4].
关键词:
phase;gd;cr;mn
Z.C. Guo
,
X.Y. Zhu
金属学报(英文版)
The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE (rare earth)-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with increasing
pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of
RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r = 0.8 is higher than that at r = 0.6.
关键词:
pulse frequency
,
null
,
null
施卫
,
侯磊
功能材料
采用超声喷涂热解淀积方法将SnO2:F透明导电薄膜制备于耐高温的硼硅玻璃管内壁.XRD物相分析及SEM、STM形貌分析表明,SnO2:F薄膜为多晶结构,平均粒径50nm.分析了薄膜中F取代SnO2中O的形成过程和薄膜电导率增强的机理,解释了不同的工艺条件对薄膜的结构、光电特性的影响,确定了制备SnO2:F薄膜加热管的最佳工艺条件.该条件下制备的薄膜的电阻率达4×10-4Ω·cm,可见光透过率高于90%,功率密度平均可达35 W/cm2.
关键词:
薄膜技术
,
SnO2:F薄膜
,
光电特性
,
超声喷涂热解法
