杨昆
,
杨祥龙
,
陈秀芳
,
崔潆心
,
彭燕
,
胡小波
,
徐现刚
人工晶体学报
使用物理气相传输方法(PVT)制备了2英寸Ti掺杂与非故意掺杂6H-SiC衬底,并对衬底进行热处理.使用拉曼光谱仪、低温光致发光谱(LTPL)和非接触电阻率测试对衬底晶型、掺杂元素和电阻率进行了表征.结果表明,Ti元素有效掺入6H-SiC中,Ti掺杂对PVT方法生长的6H-SiC衬底晶型稳定性无影响,Ti掺杂衬底与非故意掺杂衬底均为6H-SiC,热处理后Ti掺杂衬底电阻率达到1010～1011Ω·cm.初步认为Ti掺杂衬底热处理过程中产生的大浓度碳空位Vc是引起Ti掺杂样品电阻率上升的主要原因.
关键词:
物理气相传输
,
Ti掺杂
,
6H-SiC
,
电阻率
Journal of Alloys and Compounds
The structural relationship between the hydride phases in Ti-Mo-H solid solution system (Mo content up to 15 at% in the alloy) during dehydrogenation process under annealing has been studied by conventional and in situ X-ray powder diffraction and transmission electron microscopy (TEM) analysis. During dehydrogenation, the saturated hydrides of the Ti-Mo alloys with fcc delta-phase structure transfer into bcc beta-phase at higher temperatures. An associated hydrogen concentration reduction for the delta-phase hydride is observed in the process. However, as the hydrogen concentrations decrease to certain values (H/M similar to 1.1-1.7), the unsaturated delta-phase formed at high temperature would become unstable at lower temperature, and transfer into a tetragonal phase (denoted the epsilon-phase here). Unlike that of the e-phase in Ti-H system, the phase transition does not occur for the saturated delta-phase with hydrogen concentration close to the stoichiometric limit. The hydrogen concentration of this epsilon-phase hydride is in between that of the tetragonal gamma and epsilon-phase in Ti-H system, but more close to the gamma-phase. The occurrence region of this epsilon-phase expands along with the increase of the Mo content in the alloys. The phase has a lattice similar to that of the e-phase in Ti-H system with corresponding fct unit-cell c/a < 1. (c) 2007 Published by Elsevier B.V.
关键词:
hydrogen storage materials;gas-solid reactions;X-ray diffraction;titanium hydride;zirconium;alloy;diffraction;deuteride;crystallography;transformation;property;neutron
Acta Physico-Chimica Sinica
First-principles calculations were performed to determine the equilibrium crystal structures, energetic properties, and stability of Mg(x)Ti((1-x))H(2) (x=0.25, 0.5, 0.75, 0.875) systems containing different amounts of titanium using the pseudopotential plane-wave method based on density functional theory. The calculation results show that the hydrogen atoms in the Mg(x)Ti((1-x))H(2) hydrides roughly occupy the tetrahedral interstitial sites. The calculated H Ti distances are less than the H Mg distances. This indicates that Ti has a more notable affinity for hydrogen than Mg. The bonding strength of H Mg is weaker when the Ti atom attracts surrounding hydrogen atoms. The stabilization and dehydrogenation temperatures of the hydrides Mg(x)Ti((1-x))H(2) are lower than those of MgH(2) with an increasing Ti content. This indicates that titanium can reduce the decomposition temperature of the Mg(x)Ti((1-x))H(2) hydrides and play a significant catalytic role in improving the dehydrogenation dynamic properties of the Mg(x)Ti((1-x))H(2) hydrides.
关键词:
Mg(x)Ti((1-x))H(2);Crystal structure;Pseudopotential plane-wave;Stabilization;hydrogen storage;solid-solutions;magnesium;titanium;hydride;diffraction;energetics;kinetics;behavior;alloy
张诚
,
邬润德
,
童筱莉
高分子材料科学与工程
研究了Ti(OC4H9)4-MAPS体系中Ti(OC4H9)4、MAPS、C2H5OH、H2O 4个原料组分对聚钛硅氧烷溶胶-凝胶转变规律的影响.结果表明,增大水和Ti(OC4H9)4的用量或降低MAPS和C2H5OH的用量,易形成凝胶;反之,则易形成溶胶.根据大量实验数据,绘制了该体系Ti(OC4H9)4-C2H5OH-H2O三维溶胶-凝胶转变临界点网面图,并用计算机关联,得到了网面的数学表达式.
关键词:
Ti(OC4H9)4
,
MAPS
,
聚钛硅氧烷
,
溶胶-凝胶转变规律
Journal of the European Ceramic Society
Passivation behavior, corrosion kinetics and film formation mechanism of Ti(3)AlC(2) in 1 M NaOH and 1 M H(2)SO(4) solutions were investigated by linear potential scan, electrochemical impedance spectroscopy, cyclic voltammetry, SEM and XPS. The corrosion resistance mainly depended on the formation of passivating films on Ti(3)AlC(2) in 1 M NaOH and 1 M H(2)SO(4), which led to different corrosion processes. Ti(3)AlC(2) displayed good corrosion resistance in NaOH due to the formation of dense and protective Ti oxides as the passivating film. However, it exhibited poor corrosion resistance in H(2)SO(4) which attributed to the formation of permeable Ti sub-oxides as the pseudo-passivating film. (C) 2010 Elsevier Ltd. All rights reserved.
关键词:
Ti(3)AlC(2);Corrosion;Electrochemical measurements;XPS;electrochemical-behavior;passive film;ti3sic2;ti4aln3;phases;ti2aln;alloy;hcl;ti
王金淑
,
李辉
,
殷澍
,
佐藤次雄
无机材料学报
doi:10.3724/SP.J.1077.2007.00843
采用机械化学法, 利用离子交换反应, 通过离子交换、层离和沉淀过程制备了高比表面积的H 2Ti4O9纳米晶体. 采用XRD、TEM、热分析、N2吸附-脱附等温过程和吸收光谱对制备的H2 Ti4O9纳米晶体进行了表征. 结果表明, 以TiO2纳米晶片形式存在的微晶Ti4O92-, 其径向尺寸低于50nm, 纳米晶片的比表面积取决于反应溶液的pH值和对前驱物K2Ti4O9 球磨的时间. 将K2Ti4O9球磨2h后悬浮于1mol/L HCl溶液中搅拌, 进行离子交换反应, 最后将溶液pH值调整至8, 沉淀后所得产物H2Ti4O9 的比表面积达328.4m2·g-1.
关键词:
H2Ti4O9
,
nanocrystal
,
ball-milling
,
ion exchange
王金淑
,
李辉
,
殷澍
,
佐藤次雄
无机材料学报
doi:10.3321/j.issn:1000-324x.2007.05.014
采用机械化学法,利用离子交换反应,通过离子交换、层离和沉淀过程制备了高比表面积的H2Ti4O9纳米晶体.采用XRD、TEM、热分析、N2吸附-脱附等温过程和吸收光谱对制备的H2Ti4O9纳米晶体进行了表征.结果表明,以TiO2纳米晶片形式存在的微晶Ti4O2-9,其径向尺寸低于50nm,纳米晶片的比表面积取决于反应溶液的pH值和对前驱物K2Ti4O9球磨的时间.将K2Ti4O9球磨2h后悬浮于1mol/L HCl溶液中搅拌,进行离子交换反应,最后将溶液pH值调整至8,沉淀后所得产物H2Ti4O9的比表面积达328.4m2·g-1.
关键词:
H2Ti4O9
,
纳米晶
,
球磨
,
离子交换
马国佳
,
张晓囡
,
武洪臣
,
张华芳
,
彭丽平
稀有金属材料与工程
采用磁控溅射沉积万法在钛锚合金基体上制备有Ti与无Ti的类金刚石(DLC)膜,全方位离子注入(PSlI)技术被用来在膜与基体之间形成过渡层,提高膜基界面的附着力.通过X射线光电子能谱、纳米压痕、摩擦磨损等表征手段比较2种薄膜的化学组成、微结构特征和力学性能.结果表明:掺Ti α-C:H膜是含有TiC纳米晶粒的复合膜结构,其中TiC晶粒的大小约是5 nm,掺Ti α-C:H膜的力学性能得到明显改善,硬度被提高到24 GPa左右,而且结合力也明显得到提高.在大气中对样品进行热处理后,再进行摩擦磨损试验,结果表明 Ti 掺杂改善了α-C:H膜的热稳足性.
关键词:
α-C:H膜
,
类金刚石
,
PSII
,
Ti掺杂
