退火温度对HA/Ti-24Nb-4Zr复合材料组织与性能的影响

利用放电等离子烧结(SPS)技术制备了HA/Ti-24Nb-4Zr生物复合材料,研究了不同退火温度对复合材料显微组织和力学性能(抗压强度、屈服强度、屈强比、压缩弹性模量)的影响。结果表明,烧结态复合材料主要由β-Ti相、少量初生α-Ti相及HA相组成;随着退火温度的升高,复合材料基体中β-Ti相含量增多且晶粒逐渐长大,针状次生α-Ti相在晶界处和晶内不断析出,HA相结构和含量变化不大;与烧结态相比,不同退火温度处理后的复合材料强度和弹性模量先略微上升后下降,而塑韧性呈不断提高趋势;复合材料在850 ℃退火处理后,抗压强度、屈服强度、屈强比和压缩弹性模量值分别为1507 MPa、1270 MPa、0.84和42 GPa,塑韧性得到明显改善,作为生物医用植入材料具有潜在的应用前景。     

Characterisation of the microplasma spraying of biocompatible coating of titanium

This paper presents new results of studying the influence of parameters of microplasma spraying (MPS) of Ti wire on the structure and properties of Ti coatings. Based on the design of the experiment and the results of the SEM study, certain spraying modes were chosen to form the desired composition and structure of the Ti coating.  The dense sublayer (up to 300 µm thick) provides good adhesion to the substrate, and a porous top layer can accelerate the coated implant ingrowth with the bone.  This technology is developed for the manufacture of coated endoprosthesis implants.     

Improved reversible dehydrogenation properties of MgH2 by the synergetic effects of graphene oxide-based porous carbon and TiCl3

In this study, we used a combination of graphene oxide-based porous carbon (GC) and titanium chloride (TiCl₃) to improve the reversible dehydrogenation properties of magnesium hydride (MgH₂). Examining the effects of GC and TiCl₃ on the hydrogen storage properties of MgH₂, the study found GC was a useful additive as confinement medium for promoting the reversible dehydrogenation of MgH₂. And TiCl₃ was an efficient catalytic dopant. A series of controlled experiments were carried out to optimize the sample preparation method and the addition amount of GC and TiCl₃. In comparison with the neat MgH₂ system, the MgH₂/GC-TiCl₃ composite prepared under optimized conditions exhibited enhanced dehydrogenation kinetics and lower dehydrogenation temperature. A combination of phase/microstructure/chemical state analyses has been conducted to gain insight into the promoting effects of GC and TiCl₃ on the reversible dehydrogenation of MgH₂. Our study found that GC was a useful scaffold material for tailoring the nanophase structure of MgH₂. And TiCl₃ played an efficient catalytic effect. Therefore, the remarkably improved dehydrogenation properties of MgH₂ should be attributed to the synergetic effects of nanoconfinement and catalysis.     

Microstructure−fracture toughness relationships and toughening mechanism of TC21 titanium alloy with lamellar microstructure

The independent influence of microstructural features on fracture toughness of TC21 alloy with lamellar microstructure was investigated. Triple heat treatments were designed to obtain lamellar microstructures with different parameters, which were characterized by OM and SEM. The size and content of α plates were mainly determined by cooling rate from single β phase field and solution temperature in two-phase field; while the precipitation behavior of secondary α platelets was dominantly controlled by aging temperature in two-phase field. The content and thickness of α plates and the thickness of secondary α platelets were important microstructural features influencing the fracture toughness. Both increasing the content of α plates and thickening α plates (or secondary α platelets) could enhance the fracture toughness of TC21 alloy. Based on energy consumption by the plastic zone of crack tip in α plates, a toughening mechanism for titanium alloys was proposed.     

应用M-MIVM预测含钛渣系组元活度

 在钢铁冶炼过程中,随着护炉钛材料和含钛铁矿石的应用,大量的含钛炉渣被生产出来。由于缺少多元含钛渣系的热力学数据,限制了钛资源综合利用技术的深入发展。因此,应用改进的分子相互作用体积模型(M-MIVM(FII)),预测了基础渣系Al₂O₃-CaO-SiO₂、FeO-MnO-SiO₂和含钛渣系FeO-MnO-TiO₂、FeO-SiO₂-TiO₂、MnO-SiO₂-TiO₂、Al₂O₃-CaO-FeO-TiO₂中各组元活度,并与试验值比较。结果表明,M-MIVM(FII)的预测值与试验值符合较好,6个体系总的平均相对误差为11%,该精度处于Turkdogan提出的30%以内的试验误差范围; M-MIVM(FII)在参数拟合与活度预测能力方面均优于MIVM,该模型对多元含钛熔渣体系组元活度具有更好的预测效果。在此基础上,应用M-MIVM(FII)预测Al₂O₃-CaO-SiO₂-TiO₂熔体中TiO₂活度,并分析其影响因素。结果表明,TiO₂活度预测值与试验值吻合良好,且随炉渣碱度、Al₂O₃含量的增加而降低,该规律与试验规律相一致。M-MIVM(FII)仅通过拟合子二元系活度或者直接由无限稀活度系数就能够预测多元熔体的热力学性质。     

改性氧化钛对羟乙基乙二胺水溶液解吸CO2的强化

羟乙基乙二胺（AEE）水溶液的CO₂循环吸收量高（1.2molCO₂/molAEE），吸收速度快，稳定性好，但解吸速度慢、解吸量少（0.8mol CO₂/mol AEE）是限制该技术广泛应用的主要原因。本文通过向AEE水溶液中添加质量分数为0.05%～0.20%的改性氧化钛（TiO₂-MWCNT和TiO₂-OH）强化AEE的解吸能力。CO₂循环吸收（40℃）-解吸（120℃）实验结果表明改性氧化钛的添加比氧化钛强化CO₂解吸效果更好，强化顺序为TiO₂-MWCNT＞TiO₂-OH；其对应的最大解吸速率分别为0.093L/min（质量分数0.15%）和0.083L/min（质量分数0.20%），相对于AEE水溶液，分别提高了32.9%和18.6%；其对应的最大解吸量分别为0.92molCO₂/molAEE（质量分数0.15%）和0.88molCO₂/molAEE（质量分数0.20%），分别提高了12.2%和9.7%；其对应的CO₂循环吸收量分别是0.95molCO₂/molAEE（质量分数0.15%）和0.89molCO₂/molAEE（质量分数0.15%），分别提高了18.75%和11.25%；5次循环吸收解吸实验结果表明改性氧化钛强化CO₂解吸效果稳定，具有较强的化学稳定性。对反应后的改性氧化钛进行XRD、BET、FTIR和SEM表征，结果表明改性氧化钛具有较强的结构稳定性。TiO₂-MWCNT和TiO₂-OH在促进有机胺溶液解吸CO₂方面具有一定的工业应用潜力。     

聚丙烯腈/醋酸纤维素/TiO2复合纳米纤维膜的制备及其光催化降解性能

为研究碱改性前后复合纳米纤维膜的光催化降解性能,首先利用静电纺丝技术制备聚丙烯腈/醋酸纤维素/二氧化钛(PAN/CA/TiO₂)复合纳米纤维膜,依次用0.05、0.10 mol/L的氢氧化钠溶液对其进行碱处理,制得聚丙烯腈/再生纤维素/二氧化钛(PAN/RC/TiO₂)复合纳米纤维膜,并应用于染料废水处理。借助扫描电子显微镜、傅里叶红外光谱仪及接触角测量仪等手段表征了复合纳米纤维膜的结构与亲水性;同时研究了复合纳米纤维膜的力学与光催化降解性能。结果表明:经碱处理后,复合纳米纤维膜的静态接触角由125.30°减小到10.20°,亲水性能得到很大的改善;PAN/RC/TiO₂复合纳米纤维膜对亚甲基蓝(MB)溶液的降解率达到91.2%,而空白对照样对MB溶液的降解率仅为10.1%,且重复使用3次后,复合纳米纤维膜对MB溶液的降解率仍达74.7%。