Magnetic Properties of Fe-Doped Rutile

Ball-milling method was applied to dissolve Fe into titanium dioxide (TiO₂). X-ray diffraction indicated the starting anatase changed to a rutile-type structure with oxygen deficiency after ball milling. Transmission electron microscopy and X-ray absorption experiments were conducted to examine the possible existence of magnetic impurities in the ball-milled powders after they were leached in HCl solutions. Temperature dependence of the resistivity shows semiconducting behavior and the magnetic hysteresis loops at 5 and 300 K exhibit ferromagnetic characteristics. Fe-doped TiO₂ films were also prepared by pulsed laser deposition. The magnetic properties of the films are discussed.     

钛铁矿选择氯化法制取人造金红石的热力学与动力学

研究了钛铁矿选择氯化制取人造金红石反应的Fe-Ti-C-O2-Cl2系平衡图，计算了氧与某些氯化物相互作用的自由能变化，采用“通氧一步选择氯化法”，解决了选择氯化“自热”反应持续进行的技术关键，对反应参数进行了实验室，半工业和工业化生产试验研究，研究证明，选择氯化过程的动力学模型是“固体颗粒粒度保持不变的缩核反应模型”，动力学区的活性能为34．33kJ/mol；扩散区的活化能为0．80kJ/mol，研究开发的无筛板沸腾氯化炉可以长期稳定地连续运转，生产出的人造金红石品位为92．10％，经摇床和磁选，品位达到95％，床层单位炉产能达12．4t/(m2.d)，该工艺和设备已成功地应用于工业生产。     

复合捕收剂协同作用机理研究

采用苯乙烯膦酸与脂肪醇组成的复合捕收剂浮选金红石矿取得了较好效果，通过改进的Ｈａｌｌｉｍｏｎｄ管浮选试验、吸附量测定试验、捕收剂溶液表面张力和金红石表面接触角的测量以及Ｘ射线光电子能谱测试（ＸＰＳ），详细研究了复合捕收剂的协同作用机理。试验结果表明：苯乙烯膦酸在金红石表面发生了化学吸附，脂肪醇与苯乙烯膦酸相互联结，其疏水基指向水相，从而增强了金红石表面的疏水性，提高浮选结果。     

正丁醇水溶液通氨气法制备TiO2粉体

以TiCl4为原料,正丁醇和水的混合液为溶剂,通入氨气促使TiCl4水解,制备出不同粒径的TiO2粉体.由X射线衍射、场发射扫描电镜和激光粒度仪对样品进行了表征.研究了温度、pH值对粉体的晶型、形貌和粒径的影响.结果表明:在80 ℃通氨气,3≤pH≤8时,所得TiO2粉体均为锐钛矿和金红石的混相,且pH=3时制得的粉体为60 nm左右的球形颗粒,分散性很好;而pH=6,8时所得的粉体团聚严重;室温(20～30 ℃)下通氨至pH=6也可得到分散性较好的无定型态TiO2粉体,但粉体粒径增大,约170nm左右.     

液相水解法合成金红石型TiO2

提出的钛液反应水解法，改变了传统的外加晶种存在下具有工业意义的水解过程。该法无须外加晶种，选择了以酒石酸，聚丙烯酰胺为沉淀剂，絮凝剂，在常压下使钛液直接长温水解，液相共沉淀制备金红石型ＴｉＯ２。还研究了反应条件，分析了产品的特性。     

Stable structure and electronic properties of Ru1−xTixO2 rutile type solid solutions from DFT calculations

To design solid solution is an effective strategy for functional materials. The complex electron correlation and non-equilibrium atomic interaction are the primary factors to impact the macro-/micro-structure and application performances of solid solution. Hence, this article concentrates on the stable crystal structure and the corresponding electronic structure of Ru_1−xTi_xO₂ solid solution by using density functional theory calculations. Based on analyzing the atomic interaction between solute and solvent atoms, the most stable supercell models for the specific solid solubility were obtained. In Ru_1−xTi_xO₂ solid solution, solute (and solvent) atoms preferentially arrange along the [110] direction, and tend to occupy the nearest sites of identical atoms, to arrange the symmetric ordered substitution configurations. Using the subregular solution model, the mixing enthalpy can be represented by the following expression: . The calculated phase diagram is consistent with the experimental results. Thus, the calculated results in this article are reliable and can provide more meaningful information. In the cases of Ru-rich solid solutions, the metastable phase exists in the range of x < 0.27; while in the cases of Ti-rich solid solutions, the metastable phase exists in the range of x > 0.81. Interestingly, the electron density of Ru_1−xTi_xO₂ solid solutions at Fermi level has a stronger dependence on the Ru composition, which intrinsically influences its electronic structure and optical properties. According to the basic application principle, Ru_1−xTi_xO₂ solid solutions with lower (x < 0.27) and higher (x > 0.81) solid solubility could act as suitable candidate for the applications in field electrochemistry and photocatalysis.     

沉积参数对二氧化钛薄膜结构相变的影响

用磁控溅射的方法在硅衬底上制备了二氧化钛薄膜,并通过改变薄膜沉积过程中氧气含量、溅射时间、工作压强、衬底温度等溅射参数,制备了系列薄膜样品,得到了二氧化钛薄膜两种相结构的最佳生成条件.研究表明:较高的工作压强有利于金红石结构的生成;衬底加热、增加沉积时间有利于生成锐钛矿结构;氧气含量的变化对薄膜的相结构没有明显影响.     

Fabrication and Characterisation of Rutile-TiO_2 Coatings on Metallic Alloy Substrates

RUTILE-TJO2is a versatile material possessing manyinteresting physical,chemical,optical and dielectricproperties[l].It is also a good tribological material thatcan offer low friction and low wear rate[2,3].However,the application of rutile in the tribological field hasbeen limited to titanium alloys only so far,for example,by thermal oxidation of titanium alloys[4,5].Very fewinvestigations have been directed to the tribologicalapplications of rutile films on substrates other thantitanium al…     

High-temperature oxidation of pure titanium in CO2 and Ar-10%CO2 atmospheres

The oxidation behavior of pure titanium has been investigated in the temperature range of 1000 K to 1300 K in CO₂ or Ar-10%CO₂. Optical microscopy, electron probe microanalyses, and X-ray measurements on the oxide scales formed during oxidation indicate that their structures are nearly independent of temperature and the corrosion atmosphere. The scales consisted of two layers, an external one and an internal one, having a rutile (TiO₂) structure. The parabolic rate law was confirmed for growth of the external scale and the permeation depth of oxygen in titanium with apparent activation energies of 266 and 226 kJ/mol, respectively. The rate-determining diffusion species in the oxidation processes are discussed.     

Kinetics of the oxidation of ilmenite

The oxidation of ilmenite (FeTiO₃) in air and dry oxygen was investigated over the temperature interval 600 to 970°C. Dense platelets of ilmenite crystals as well as powder samples of ilmenite were oxidized. The weight data were recorded employing a thermobalance. The oxidation kinetics of ilmenite platelets were parabolic except for the initial stages during which logarithmic kinetics were observed. For powder samples the logarithmic rate law was followed primarily. The logarithmic rate law was attributed to free penetration of oxygen through cracks and short-circuit paths. The activation energies associated with the logarithmic rate law were nearly one-half of those obtained from parabolic oxidation. The growth morphology of the products of oxidation of ilmenite was observed with a scanning electron microscope. The effect of growth morphology on the kinetics is discussed, and a probable reaction mechanism is suggested for the oxidation of ilmenite.