Mechanical and Tribological Properties of Ca/P-Doped Titanium Dioxide Layer Produced by Plasma Electrolytic Oxidation: Effects of Applied Voltage and Heat Treatment

Plasma electrolytic oxidation (PEO) is a technique that produces a hard oxide layer on the titanium surface where its properties can be tailored by changing the process parameters or by a posterior heat treatment (HT). In this work, a TiO₂ layer with different crystallinity was produced by PEO with different applied voltages (250 to 400 V) and post-HT at 600°C. Our aim was to evaluate the influence of the PEO voltage and HT on the mechanical and tribological properties of anodized Ti. There is an increase in pore size, oxide thickness, and Ca/P ratio for the oxide layer with the applied voltage during the PEO process. X-ray diffraction (XRD) results indicated an increase in the crystalline rutile phase in the oxide layer with voltage and HT. Nanoindentation shows an increase in the oxide hardness and elastic modulus with increased voltage and HT, leading to an improvement in the wear resistance.     

Ce掺杂改性TiO_2对MNO_x/Ce-TiO_2体系催化活性的影响

以Ce掺杂的TiO2粉体为载体,MNOx为活性组分,制备了MNOx/Ce-TiO2体系SCR催化剂,利用TG-DSC,XRD,SEM及EDS考察了Ce的掺杂对MNOx/TiO2体系活性的影响,采用模拟烟气分析装置测试催化剂的活性。结果表明：Ce离子的掺杂阻碍了TiO2粒子由锐钛矿型向金红石型的转变,拓宽了锐钛矿型TiO2的使用温度范围。TiO2粉体粒子在锐钛矿型状态下,颗粒分散较为均匀,并且无明显团聚现象,保证了较高的比表面积,催化剂的SCR催化活性比未掺杂的催化剂活性有明显的提高。     

金红石型钛白粉在醇酸调和漆中的应用

醇酸调和白漆常使用锐钛型钛白粉作为颜料,但涂膜的耐候性和使用寿命不尽如人意,改用耐候性更好的金红石型钛白粉作为着色颜料,在保光性、保色性、耐久性等方面都有大幅提高,是值得大力推广的第二代醇酸调和漆。     

盐酸直接浸取钛铁矿制取人造金红石

研究了盐酸直接浸取钛铁矿制取金红石的方法，探讨了搅拌条件、盐酸浓度、浸取时间、温度、矿粉粒度对浸取效果的影响，利用Ｘ－粉末衍射证明所得产物实现了由锐钛型至金红石型的转型，得到了浸取过程的最佳工艺条件为盐酸浓度６．２７ｍｏｌ／Ｌ；浸取温度１１０℃；液固比４：１（质量）；颗粒粒径３００目以下     

NiTi合金表面镍离子释放的电子结构理论计算

采用电荷自洽离散变分Xα方法，对NiTi合金表面生成TiO2氧化层时镍的释放行为进行了理论计算。选取TiO2的主要晶态金红石构型，通过构造合理的团簇模型，计算镍离子在金红石（110）和（100）表面扩散的可能性及其强度大小。对键级、电荷分布，以及态密度的计算结果进行分析显示，当NiTi合金表面形成金红石型TiO2表面膜时，由于镍原子与氧原子之问发生有效的共价成键作用，会抑制表面镍离子的溶出，即从理论上验证了在NiTi合金表面制备金红石型TiO2氧化膜将有利于提高其生物相容性。     

XRD Investigations of the Phosphorus Effect on the Oxidation of TiAl Alloys by High-Resolution Methods

Recently it has been found that very small amounts (a few 100 ppm) of Padded to -titanium aluminide can significantly alter the oxidationbehavior between 973 and 1273 K. The mechanism responsible for this changeis, however, still not clear. In the present study, phosphorus wasincorporated into the surface of TiAl (containing 50 at.% Al) by ionimplantation and oxidation tests were carried out at 1173 K inair. Improvement of oxidation resistance is only temporary up to 100 hr forphosphorus-implanted TiAl. After 100 hr, the oxidation rate increases andbreakaway oxidation follows. XRD and EPMA showed that the breakawayoxidation is connected with massive nitride formation. Two different modelsare proposed which can explain the effect of phosphorus additions on theoxidation kinetics of TiAl during the protective stage within the first100 hr. The breakaway effect can be explained by penetration of air to themetal–oxide interface zone because of microcrack formation in theoxide scale, which was experimentally proved by acoustic-emission analysis.     

钽掺杂金红石TiO2电子结构的第一性原理研究

采用第一性原理中的CASTEP模块计算了金红石相TiO2掺杂过渡金属钽元素的能带结构以及态密度。计算结果表明，Ta原子替换Ti原子后，Ta的5d轨道对TiO2的导带影响较明显，且使TiO2的带隙宽度减小，这样有可能使金红石TiO2吸收带出现红移现象或产生在可见光区的吸收，其中Ta原子的t2g态起了重要作用。     

青海丁叉叉山地区金红石矿床地质特征及找矿前景

丁叉叉山地区金红石矿床位于柴北缘成矿带东端,为近年新发现的大型金红石矿床。矿床产于古元古界金水口群地层榴辉岩体中,严格受榴辉岩体的控制。呈条带状、透镜状产出,近东西向展布。成因类型属榴辉岩型金红石矿床,成矿时期为加里东期。在总结区内矿床地质特征的基础上,进而与国内苏鲁榴辉岩金红石矿床、省内鱼卡榴辉岩型金红石矿床等典型矿床对比分析,研究表明:区内榴辉岩成矿条件有利,保存条件良好,具有较好的找矿前景。     

Adsorption behavior and mechanism of Bi(III) ions on rutile–water interface in the presence of nonyl hydroxamic acid

The adsorption behavior and mechanism of Bi(III) ions on the rutile–water interface were investigated through micro-flotation, Zeta potential measurement, adsorption amount measurement and X-ray photoelectron spectroscopy (XPS). According to the results of micro-flotation, Bi(III) ions could largely improve the rutile flotation recovery (from 62% to 91%), and they could increase the activating sites and reduce the competitive adsorption between nonyl hydroxamic acid negative ions and OH^? ions, which determined that Bi(III) ions were capable of activating rutile flotation. The adsorption of Bi(III) ions onto the rutile surface led to the shift of Zeta potential into the positive direction, which was good for the adsorption of nonyl hydroxamic acid anions. In addition, the results of XPS indicated that the chemical environment around Ti atom had not changed before and after the adsorption of Bi(III) ions. Based on the adsorption mechanism of Bi(III) ions, it was deduced that firstly Bi(III) ions occupied the vacancies of the original Ca²⁺, Mg²⁺ and Fe²⁺ ions on the rutile surface; secondly Bi(III) ions covered on the rutile surface in the form of hydroxides.     

锆硅包膜金红石型钛白粉工艺优化及性能

采用溶胶–凝胶法制备了锆硅包膜金红石型钛白粉。通过正交实验研究了浆液浓度、分散剂用量和Zr O2、Si O2两种包膜剂含量对锆硅包膜金红石型钛白粉的影响,得到了制备锆硅包膜金红石型钛白粉的优化工艺条件。采用Nano-ZS型粒度仪、扫描电子显微镜、透射电子显微镜和能谱仪、Fourier红外光谱仪等测试手段,考察锆硅包膜金红石型钛白粉的效果和包膜机理。结果表明:金红石型钛白粉表面包覆了两层均匀而致密的Zr O2膜和Si O2膜。包膜后金红石型钛白粉的失光率、吸油量和遮盖力都有所下降,白度值增加。同时,证实了这两层膜是以化学键Zr-O-Ti和Si-O-Zr的形式结合在金红石型钛白粉颗粒表面。