S. Abubakir
,
Y.S. Wu
,
T.C. Zhang
,
Z. Yang and Z. Zhang (Department of Surface Science & Corrosion Engineering
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)(Department of Materials Science and Engineering
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
Samples of FJ316 stainless steel powder alloyed with different amounts of glass2 material have been compacted at the pressure of 686MPa and sintered at 1160, 1180,and 1200℃, in hydrogen atmosphere for one hour. The materials have been subjected to microstructure characterization, tensile strength, handness, impact toughness and corrosion testing. The effect of the experimental process parameter has been evaluated and the importance of porosity, sintered temperature, glass content and its grain size in determining mechanical and corrosion properties has been confirmed. Glass has a strong effect on the mechanical properties and produces brittleness when added to FJ316SS. Very good corrosion resistance has been achieved by comparing this result with the corosion resistance of sintered pure stainless steel. The results of this study permit optimization in the production of glass alloyed P/M FJ316SS, with respect to mechanical properties and high corrosion resistance.
关键词:
corrosion rate
,
null
,
null
,
null
,
null
Y.S. Wu
材料科学技术（英文）
Mesoporous alumina γ-Al2O3 with high specific surface area and large pore volume is prepared by using a facile reverse precipitation method from sodium aluminate and nitric acid. The effects of terminal pH value, aging time and thermal stability on the characterization of γ-Al2O3 are studied by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) method and scanning electron microscopy (SEM). The results show that γ-Al2O3 with better properties can be obtained by changing the preparation parameters. High BET surface area of 340 m2/g can be obtained by calcining at 500 °C for 4 h with large pore volume of 0.90 cm3/g and average pore size of 7.6 nm. After calcining at 1000°, the surface area is still 86 m2/g and the pore volume is 0.37 cm3/g.
关键词:
Mesoporous alumina
,
null
,
null
王龙妹
,
杜挺
金属学报
用直接平衡法研究了1500,1550,1600℃Ni液中Y-S平衡关系,测定了钇的脱硫常数lgK_(YS)及Y,S的一阶活度相互作用系数e_S~Y与温度的关系,并进行了有关的热力学计算。由测得的数据算出Ni液中YS的标准生成自由能△G_((Y)S),钇的标准溶解自由能△G_((Y)(l)→[Y]Ni),活度系数γ_Y~o,以及钇的克原子分数自相互作用系数∑_Y~Y和百分浓度自相互作用系数e_Y~Y与温度的关系。 对于反应[Y]_(Ni)+[S]_(Ni)=YS_(s) △G_((Y)S)=-215000+95.53T(cal/mol)脱硫常数: lgK_(YS)=-47000/T+20.86 e_S~Y=-350200/T+179 △G_((Y)(l)→[Y]Ni)=126200-79.31T(cal/mol) lgγ_(Y)=27584/T-15.151 ∑_Y~Y=-127T05/T+69.79 e_Y~Y=-364.8/T+0.2018
关键词:
LI Guodong
,
D U Ting
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China LI Guodong
,
Department No.16
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
100081
,
China
金属学报(英文版)
The thermodynamic properties of Cu-Ce-S and Cu-Y-S liquid solutions were studied by the chemical equilibrium technique at 1200℃. The equilibrium constants and the standard free energies of formation of CeS and YS were determined for the reactions: CeS=[Ce]+[S] and YS = [Y]+[S] . For the solution of Ce_(1) and Y_(l) in pure Cu according to the reactions: Ce_(1)= [Ce] and Y_(1)= [Y] , the standard free energies of solutions were obtained. The first order and second order interaction coefficients between solute elements as well as the activity coefficients γ_(Ce)~0 and γ_Y~0 in liquid Cu were also determined.
关键词:
Cu-Ce-S system
,
null
,
null
王龙妹
,
杜挺
金属学报
由低温无水电解稀土夹杂物和固体电解质定氧活度测得Ni液中钇的脱硫氧常数与温度的关系:lgKr_2o_2s=-(33146)/T+3.85,(1500-1600℃)钇的硫氧化物在Ni液中的标准生成自由能与温度的关系:2[Y]+2[O]+[S]=Y_2O_2S_(s),(1500—1600℃)△G°=151640+17.61T(cal/mol)=-634460+73.69T(J/mol)由实验测得数据经热力学分析计算得到1600℃Ni液中[Y]-[S]-[O]平衡立体图及α_o-α_s平衡相图,为理论上预测夹杂物生成的先后次序及类型提供了依据.并给出了Ni液中加钇控制夹杂物形态公式,钇的加入量与氧,硫含量之间的函数关系.
关键词:
李铂
,
周建江
,
夏伟杰
,
吴连慧
液晶与显示
doi:10.3788/YJYXS20142904.0605
直线是机载座舱显示画面中最基本的图元,其显示质量对于整个画面的显示效果影响较大,尤其是小角度下直线显示的“麻花”现象一直是影响显示效果的关键问题之一.为了提高小角度下直线的显示效果,本文提出了一种基于Wu算法的亮度渐变改进算法.该算法通过渐进地展现直线从轴方向上的亮度变化过程,减少亮度畸变,有效地改进了显示效果.通过Matlab仿真和FPGA实现,验证了该算法反走样后的小角度直线显示效果明显优于其他算法,而且结合中点画线法后,绘制时间与Wu算法相当.同时该算法还可改善大角度直线和圆弧的显示效果,消除了大角度直线的边缘锯齿,解决了圆弧在小角度部分的虚化问题.因此本文算法可用于对实时性和显示效果要求高的机载座舱显示系统,以缓解飞行员的视觉疲劳.
关键词:
座舱显示
,
反走样
,
改进Wu算法
,
小角度
,
FPGA实现
Yan NIU
,
Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)F. Gesmundo and F. Viani (Instituto di Chimica
,
Facolta di Ingegneria
,
Un
材料科学技术（英文）
The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe
关键词:
材料科学技术（英文）
The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.
关键词:
high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation
Materials Science & Engineering C-Biomimetic Materials Sensors and Systems
The bio-corrosion properties of Mg-Zn-Mn alloys with and without Y in Hank's solution at 37 degrees C were investigated by using electrochemical test and electrochemical impedance spectra (EIS). The results of open circuit potential (OCP) and polarization tests indicated that Y could reduce the cathodic current density. A passivative stage appeared in the Tafel curve of the Y containing magnesium alloy, indicating that a passivative film was formed on the surface of the Y containing magnesium alloy. EIS results showed that the Y containing alloy had higher charge transfer resistance and film resistance, but lower double layer capacity than the alloy without the Y element. The surface reaction product identification by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed that the surface corrosion products were hydroxide and phosphate (Mg(3)Ca(3)(PO(4))(4)) for Mg-Zn-Mn alloy and phosphate (MgNaPO(4)) for the Y containing Mg-Zn-Mn alloys. The XPS results also showed that a Y(2)O(3) protective film was formed on the surface of the Y containing magnesium alloy which contributed mainly to the low cathodic current density and the high resistance. (C) 2009 Elsevier B.V. All rights reserved.
关键词:
Magnesium alloy;Corrosion properties;Y(2)O(3);Electrochemical;impedance spectra;Biomedical materials;quasi-crystalline particles;in-vivo corrosion;magnesium alloys;mechanical-properties;microstructure;phase
