Evaluation of the reactivity of titanium with mould materials during casting

A methodology for evaluating the reactivity of titanium with mould materials during casting has been developed. Microhardness profiles and analysis of oxygen contamination have provided an index for evaluation of the reactivity of titanium. Microhardness profile delineates two distinct regions, one of which is characterised by a low value of hardness which is invariant with distance. The reaction products are uniformly distributed in the metal in this region. The second is characterised by a sharp decrease in microhardness with distance from the metal-mould interface. It represents a diffusion zone for solutes that dissolve into titanium from the mould. The qualitative profiles for contaminants determined by scanning electron probe microanalyser and secondary ion mass spectroscopy in the as-cast titanium were found to be similar to that of microhardness, implying that microhardness can be considered as an index of the contamination resulting from metal-mould reaction.     

Models for the formation of poly(butylene terephthalate): effect of water on the kinetics of the titanium tetrabutylate-catalysed reactions: 3

In an effort to investigate the mechanism of catalysis of titanium tetrabutoxide on the polycondensation of poly(butylene terephthalate), alcoholysis and hydrolysis reactions were studied with the aid of model molecules. The retarding effect of water has also been taken into account. Appropriate kinetic equations are derived and discussed and the results compared with experimental data obtained at different molar ratios of reactants.     

B2O3/TiO2-ZrO2催化剂上环己酮肟的气相Beckmann重排反应

用共沉淀法制备了TiO2-ZrO2复合氧化物载体，BET，DTA，XRD表征结果表明，该复合载体具有较大的比表面和较好的热稳定性，对于环己酮肟气相Beckmann重排反应制己内酰胺，用复合载体制备的B2O3／TiO2-ZrO2催化剂，比分别以TiO2,ZrO2为载体所制备的B2O3/TiO2和B2O3／ZrO2催化剂具有更高的活性和选择性，实验表明，催化剂表面中等强度的酸位是环己酮肟气相Beckmann重排反应的有效活性中心。     

Magnetism in SiC implanted with high doses of Fe and Mn

High concentrations (0.1–5 at.%) of Mn or Fe were introduced into the near-surface region (≤2000 Å) of 6H-SiC substrates by direct implantation at ～300°C. After annealing at temperatures up to 1000°C, the structural properties were examined by transmission electron microscopy (TEM) and selected-area diffraction pattern (SADP) analysis. The magnetic properties were examined by SQUID magnetometry. While the Mn-implanted samples were paramagnetic over the entire dose range investigated, the Fe-implanted material displayed a ferromagnetic contribution present at <175 K for the highest dose conditions. No secondary phases were detected, at least not to the sensitivity of TEM or SADP.     

注入氮离子的SiC涂层阻氢性能研究

利用离子束混合－离子注入（Ar^ ）和磁控溅射相结合的实验技术在HR－1不锈钢基体上制备了注入N^ 的SiC涂层，并用表面分析手段对所制备涂层的表面形貌，剖面形貌、相结构，表面成分，表面元素的化学态进行了分析，结果表明：制备的涂层结构致密，表面平整、膜层成分均匀；涂层与基体之间形成了一明显的过渡层，增强了涂层和基体之间的结合力，用二次离子质谱（SIMS）对充氘涂层的阻氢性能进行了定性分析，结果表明，涂层元素与氢形成稳定的化学键，抑制了氢的扩散和迁移，使得涂层具有一定的阻氢能力。     

超强吸水树脂的吸水性能研究

对自制的超强吸水树脂的吸收性能进行了研究，分别考察了吸水树脂的粒径，溶液的pH值，几种离子如Na^ ,K^ ,Ca^2 ,Mg^2 等的水溶液对吸水树脂吸收性能的影响。实验结果表明，在pH为6－8，树脂粒径为100mesh-120mesh时，树脂的吸水性能最好，各种离子对吸水树脂吸收性能的影响大小顺序为：Na^ ＜K^ ＜Mg^2 ＜Ca^2 。     

CHARACTERIZATION OF Si_(1-x-y)Ge_xC_y FILMS GROWN BY ION IMPLANTATION AND SUBSEQUENT SOLID PHASE EPITAXY

Si1-x-yGexCy ternary alloy films were grown on monocrystalline silicon substrates by C ion implantation and subsequent solid phase epitaxy (SPE). Two-step anneal-ing technique was employed in the SPE. The structure and electrical properties of the alloy films were determined using Fourier transform infrared spectroscopy and van der Pauw Hall measurements, respectively. With the optimization of two-step anneal-ing technique for the implanted Si1-x-yGexCy layers, a certain amount of C atoms occupied substitutional sites and no SiC was formed.     

钛硅选择性氧化催化剂的研究进展

过渡金属钼、钨、钛、钒等的高价态络合物能有效催化有机过氧化物进行烯烃的环氧化反应。以Ｍｏ（Ⅵ）络合物在有机相中催化过氧化烃来氧化丙烯生产环氧丙烷的方法称之为间接氧化法，是生产环氧丙烷的主要方法之一。７０年代初，荷兰Ｓｈｅｌ研究所发现Ｔｉ（Ⅳ）高分散负...     

钛合金的银脆,镉脆敏感性及其控制

利用慢应变速率拉伸技术（ＳＳＲＴ），并结合恒载实验，较全面地研究了Ｔｉ－６Ａｌ－４Ｖ合金的银脆行为、固态与液态镉脆行为，确定了应变速率、接触条件、热处理制度、试样取向、温度等因素对Ｔｉ－６Ａｌ－４Ｖ合金银脆与镉脆敏感性的影响，探讨了Ｎｉ阻挡层对控制Ｔｉ－６Ａｌ－４Ｖ合金和ＴＣ１１合金银脆开裂的作用。