稀土离子掺杂对于TiO2结构和光催化性能的影响

通过溶胶凝胶法制备了不同质量浓度稀土离子掺杂的TiO2,在测试其对碱性藏花红的降解效果后发现,RE3+＞RE2+＞RE4+.经过对样品进行X射线粉末衍射(XRD)、傅立叶变换红外光谱(FT-IR)、拉曼光谱(Raman)、紫外可见漫反射光谱(UV-Visible DRS)以及X射线光电子能谱(XPS)表征后,稀土离子尽管有较大的半径但是主要还是掺杂到晶格中.稀土离子掺杂对TiO2的影响主要有①抑制由锐钛矿到金红石的转变;②提高光吸收率;③抑制载流子复合.     

新显色剂2,4-二氯苯基荧光酮分光光度法测定钛的研究及应用

研究了钛-2,4-二氯苯基荧光酮(DClPF)-吐温-40三元络合物的显色反应条件及应用.结果表明,在0.02～0.11mol·L-1的硫酸介质中,在Tween-40存在下,Ti( )与试剂形成1∶4的红色络合物.最大吸收在542nm波长处,表观摩尔吸光系数为2.10×105L·mol-1·cm-1,钛含量在0～14μg/25ml范围符合比耳定律,方法灵敏,选择性较高,操作简便,在掩蔽剂存在下,可不经分离直接测定合金钢标准样品中的微量钛,结果满意.     

草酸在钛阴极上还原为乙醛酸的反应机理探讨

继首次报道用金属钛(Ti)作阴极,还原草酸制乙醛酸的电极评价研究之后,本文探讨草酸在钛阴极上电还原为乙醛酸的反应机理。提出一种 EC 模型.又用稳态近似理论建立该机理的可供实验检验的模型数学。经 LSV 极化曲线测试验证,该机理与实验结果相吻合。     

钒钛高炉渣中氮化钛的物相分析(蒸馏-库仑滴定法)

本文采用 1:2HCl将氮化钛与其它氮化物分离,将分离出的TiN残渣加浓H_2SO_4-K_2SO_4加热冒烟使其分解,加入过量的NaOH,加热蒸馏,以溴化钠作电解液,用双铂电极在30mA恒电流下进行电解,终点以死停终点法指示。终点到达时停止电解,记录电解时间,以此计算TiN的含量。     

钛-镁体系烯烃聚合催化剂中钛离子状态的EPR研究

利用EPR法研究了MgCl_2-n-BuOH-SiCl_4-TiCl_4/Al(i-Bu)_3体系催化剂中钛离子的状态,发现催化剂体系中存在(Ⅰ)、(Ⅱ)、(Ⅲ)和(Ⅳ)四种类型的Ti~(3 )离子的顺磁物类,其EPR信号分别为g=1.99,g_Δ=1.97,g_Δ=1.95和g_Δ=1.88,前三者为处于不同畸变配体场中的非烷基化Ti~(3 )离子,在烯烃聚合中不起活性中心作用.带有Cl空配位的烷基化Ti~(3 )离子是活性的物类,但其中只有少部分呈弧立状态的(Ⅳ)型离子对EPR有贡献,大部分可能通过氯桥键合,在MgCl_2表面上形成聚集体或TiCl_3分散粒子而成为EPR无声的物类.     

植入用钛合金经模拟体液浸泡后的超高周疲劳性能

为预测植入用Ti6A14V钛合金的使用寿命,研究其体液环境下的超高周疲劳性能,将退火态Ti6A14V钛合金试样恒温37℃在人工唾液和林格一洛克氏溶液中预浸泡2周．利用超声疲劳试验技术对预处理过的试样进行疲劳测试;利用电子显微镜观察疲劳断口,研究其裂纹萌生机理．结果表明,2种模拟体液浸泡后材料在107周次前的高应力范围内,疲劳强度均降低且裂纹一般萌生于试样表面;而在107周次后的超长寿命域,疲劳强度均跟未处理试样数据接近．且裂纹在内部萌生．主要由内部缺陷附近α相滑移引起．     

Influence of beam current on microstructure of electron beam melted Ti-6Al-4V alloy

The defect microstructure of the samples manufactured from Ti-6Al-4V powder was studied using electron beam melting (EBM) in the beam current range of 17 - 13 mA. The hybrid digital complex combined positron lifetime spectroscopy and coincidence Doppler broadening spectroscopy was used to characterize the defect structure of the materials. The microstructure and defects were also analyzed by transmission electron microscopy. It has been established that the main type of the defects in the EBM manufactured samples is dislocations. According to the conducted measurements and calculations, the dislocation density in the EBM manufactured samples exceeds by two orders the similar value for the cast Ti-6Al-4Valloy. Formation of Ti-Ti-Al nanoscale clusters has been found in the EBM manufactured samples.     

AgCuTiZr钎料激光钎焊钛/钢连接机理与接头性能

钛和钢广泛应用于“陆海空天”等领域,由于钛与钢的物理化学性能差异,连接界面常形成大量脆性金属间化合物,限制了其广泛应用。在分析钛/钢异种材料焊接的基础上,采用激光钎焊工艺,利用自行研制的AgCuTiZr钎料进行了钛/钢连接实验研究。结果表明,该活性钎料对基体材料润湿性良好,钎焊层组织致密、表面平整;在结合界面处出现了活性元素的扩散,钎焊层中有多物相共存,界面间实现了化学冶金结合;AgCuTiZr活性钎料激光钎焊层具有较高的硬度,达到基体材料的1.5倍,耐磨性与被连接材料45钢/TA2基本一致,抗拉强度达到595 MPa,实现了两种被连接材料的可靠连接。激光热源的显著优点适合于异种金属材料的钎焊连接。     

钢管高钛矿渣砂超高强混凝土短柱轴压力学性能试验研究

为研究钢管高钛矿渣砂超高强混凝土短柱的轴压力学性能,完成了10根钢管高钛矿渣砂超高强混凝土短柱轴压试验,重点考察高钛矿渣砂取代率对其力学性能的影响。结果表明：高钛矿渣砂取代率对钢管混凝土试件的破坏形态、荷载-位移曲线、应力-应变曲线、应力-横向变形系数曲线规律无明显影响,试件均为剪切破坏模式;随着高钛矿渣砂取代率的增加,钢管混凝土试件的承载力与初始刚度随之增加,在取代率为60%时,均达到最大值;由于核心混凝土强度过高,试件含钢率偏小,钢管对核心混凝土约束效应有限,实测承载力小于规范计算承载力。     

Microstructure evolution and mechanical properties of Ti-8Nb-2Fe-0.2O alloy with high elastic admissible strain for orthopedic implant applications

A Ti-8Nb-2Fe-0.2O(wt.%) alloy with high strength,high elastic admissible strain(δ) and low cost was designed using d-electron theory combined with electron-to-atom ratio(e/a) approach.Interstitial oxygen was introduced to strengthen the matrix of the alloy.The β-solution treated alloy was mainly composed of α " martensite with internal {111}_(α") type Ⅰ nano-twins.The α " martensite with hexagonal-like crystal structure caused by interstitial oxygen showed a high strength of 1.1 GPa but limited ductility.The alloy generated equiaxed fine-grained a phase embedded by β matrix via hot rolling and subsequent annealing in α+β phase field.The obtained alloy indicated a good combination of mechanical properties with ultimate tensile strength,Young's modulus,ductility and δ value of 1029 MPa,74 GPa,21% tensile elongation and 1.32%,respectively.These findings demonstrate that interstitial oxygen and martensitic nano-twins can be used to strengthen the soft α" martensite and high elastic admissible strain can be obtained by formation of equiaxed fine-grained α phase embedded by βmatrix in this Ti-8Nb-2Fe-0.2O alloy for orthopedic implant.