钛合金表面TiAlN膜层的制备

为了研究不同偏压对TiAlN薄膜性能的影响以及薄膜体系膜基硬度比随载荷的变化关系,采用多弧离子镀的方法在Ti6Al4V合金表面制备TiAlN薄膜,利用扫描电子显微镜、x 射线衍射仪、全自动显微硬度计等设备对膜层的微观组织结构和力学性能进行了测试.结果表明,TiAlN膜层由Ti2AlN(hcp)相组成.在恒定载荷条件下,体系的膜基硬度比随载荷的增加而减小.当载荷小于300g时,偏压对膜基硬度比与载荷关系曲线呈不规则影响.载荷超过300g以后,几乎没有影响.     

Preparation of material surface structure similar to hydrophobic structure of lotus leaf

Nano/micro replication, a technique widely applied in the microelectronics field, was introduced to prepare the hydrophobic bionics microstructure on material surface. Poly（vinyl alcohol） （PVA） and polystyrene （PS） moulds of the mastoid microstructure on lotus leaf surface were prepared respectively by the nano/micro replication technology. And poly（dimethylsiloxane） （PDMS） replicas with the mastoid-like microstructure were prepared from these two kinds of polymer moulds. Scanning electronic microscope （SEM） was employed to investigate the morphology and microstructures on moulds and replicas. Both the static and dynamic contact angles between water droplet and PDMS replicas＇ surface were also measured. As a result, similar microstructure can be observed clearly on the surface of PDMS replicas and the static contact angle on PDMS replicas was enhanced dramatically by the existence of these microstructures.     

Grafting modification on the surface of titanium dioxide by polystyrene

Based on the technology of titanium dioxide grafting modification with polystyrene (PS), the modification mechanisms are studied and the polystyrene-grafting states on the surface of titanium dioxide have been set up. Under the synergistic actions of mechanical force, chemistry and heat, macromolecular free radicals of PS are created, at the same time, the O-O bonds of titanium dioxide are broken and the oxide free radicals produced, and the numbers of oxygen atom are increased and crystal lattice defects rich electrons are formed on the surface of titanium dioxide. The radical polymerization is the main reaction between PS and titanium dioxide and C-O bonds form in the process of modification. Multi-sites chemical adsorption also exists besides grafting between PS and titanium dioxide.     

相转移法制备二氧化钛粉体的工艺研究

分别以草酸铵饱和溶液、加氨水的草酸铵饱和溶液、碳酸铵饱和溶液3种无机相与四氯化钛正辛醇溶液的有机相反应,制备二氧化钛(TiO2)粉体.通过热重分析、XRD物相分析和成分分析,研究了工艺条件和粉体的性质.结果表明,有机相溶液有效抑制了四氯化钛在水相溶液中的水解成核速率和晶核生长速率.草酸铵饱和溶液和加氨水的草酸铵饱和溶液促进成核速率,抑制生长速率,产物难以过滤洗涤,纯度难以保证.碳酸铵饱和溶液促进晶核生长速率明显,产物易于过滤洗涤,是制备高纯粉体的有效途径.实验获得了含量为99.9647%的TiO2粉体,是制备金红石单晶原料粉体的潜在途径.     

Preparation of wear resistant materials by melting and diffusion process

A wear-resistant material reinforced with VC_p was manufactured by the in-mold melting process, in which the high-vanadium alloy-rods were melted by high temperature liquid steel and elements diffused into the liquid. Microstructure of the material was examined by OM, SEM, and XRD, and alloy elements in the diffusion layer were studied by EDS, and the hardness of the material was tested by HRS. The experimental results show that the material gradually changes hardness, which is due to the uniformly existents of carbide particles on martensite matrix and the gradient distribution of vanadium and carbide.     

Preparation of calcium phosphate coating on pure titanium substrate by electrodeposition method

The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with an electrochemical work-station supplying a direct current power at potential of -0.8V (vs SCE). The electrolyte consists of 7 mmol·L-1 CaCl2·2H2O, 3 mmol·L-1 Ca(H2PO4)2·H2O and 2.5% H2O2. NaOH and HCl solutions were used to adjust pH value. The deposited samples were characterized by X-ray diffraction and scanning electron microscope. The comparison of the deposits obtained at lower and higher pH values demonstrates that the crystallization process at the interface is favoured by high pH value. With temperature increasing, the deposited hydroxyapatite is occasionally of plate-like shape, and the width and the length of the deposited calcium phosphates at 65 ℃ are larger than those at 55 ℃. Therefore, it is confirmed that the morphology and microstructure of electrochemically deposited calcium phosphates can be regulated. Additionally, the coating formed in electrolyte with H2O2 additive is homogeneous and the evolution of H2 bubble can be eliminated.     

激光重熔制备TA1表面Ni/Al复合抗高温氧化涂层

为了提高纯钛的高温抗氧化性能,采用电弧喷涂和等离子喷涂方法在纯钛表面制备Ni/Al复合涂层.利用激光重熔使得Ni层与Al层发生冶金反应,对试件进行800℃×40 h连续氧化.根据生成的金属间化合物特征研究纯钛的高温抗氧化行为.结果表明,经过表面改性处理后Ni/Al复合涂层可以显著提高纯钛的高温抗氧化性能.在激光重熔过程中Ni/Al复合涂层中的Al发生熔化扩散并与Ni形成以Ni₂Al₃相为主的扩散层.在氧化过程中Ni/Al复合涂层表面形成连续且致密的α-Al₂O₃氧化膜与大量NiAl相,表面扩散层中的富铝相可为表面提供充足的Al元素,进而对纯钛基体提供有效的高温抗氧化保护作用.     

Effect of temperature on microstructure ofmolybdenum diffusion coating on titanium substrate

The halide-activated pack cementation process was used to form molybdenum diffusion coating on titanium substrate. The morphology, structure, elements diffusion distribution and microhardness of the coatings formed at different diffusion temperatures were studied. The results indicate that the coating is made up of deposition layer and diffusion layer, and the surface roughness of specimens is increased after diffusion. In the diffusion layer, the major phases are Mo and β-Ti phase with addition of α′-Ti phase and α″-Ti phase. And the phase composition of Mo →β→α″→α′ is formed for different Mo contents in the diffusion layer from outside to inside. The diffusion of Ti element is very obvious as well as Mo element. With increasing the diffusion temperature, the thickness of diffusion layer is increased rapidly, and the microhardness is changed more smoothly with diffusion depth, which shows the same distribution rules as the Mo content.     

硫离子掺杂纳米TiO2粉体的制备及表征

以TiCl4为原料,以硫脲为掺杂物质,用溶剂热法制备了硫元素掺杂的纳米TiO2粉体。采用XRD,FTIR,TEM,UV-VIS等方法分别对样品的物相结构,形貌以及光吸收性能进行了表征。通过样品对硝基苯的降解对其光催化活性进行了测试,结果表明硫元素掺杂后的TiO2在可见光下具有较好的光催化氧化性能。     

Preparation of porous structures on copper microchannel surfaces by laser writing

A laser writing method is developed to fabricate porous structures on copper microchannel wall surfaces for enhanced microchannel heat sinks(MHSs). The formation feasibility together with its mechanism of such porous structures is explored by the comparison of dry and wet laser writing process, i.e., in both air atmosphere and under de-ionized water. Rectangular microchannels with ripples-like porous structures on the wall surfaces, which consisted of numerous micro-holes and micro-cavities,have been successfully formed in the dry laser writing process. Nevertheless, the microchannel wall surfaces were hardly altered in wet conditions. Besides, the effect of laser fluence on the formation of porous structures on the microchannels was also assessed in both dry and wet conditions. In dry laser writing process, the microchannel depth and surface roughness of wall surface increased monotonically, whereas the microchannel bottom width decreased continuously with increasing the laser fluence. On the other hand, the microchannel wall kept almost unchanged with smooth surfaces with increasing laser fluence in wet conditions.     

疏水表面冷凝的毛细力微操作液滴动态分配

为实现毛细力操作液滴获取,提出基于疏水表面冷凝的毛细力微操作液滴分配方法,研究微对象转移进程中(拾取-释放)所需的操作液滴条件.针对操作液滴分配任务,建立液桥拉伸进程中的模型.基于VOF(volume of fluid)方法,建立平面-平面、平面-球面配置模式下的动态模型,分析操作液滴的动态获取过程.仿真结果表明:接触角和提升速度均对辅助液滴的获取率和断裂距离起到重要作用,液滴趋向于接触角小的端面,提升速度可促使液滴在两平面均分.液桥体积对辅助液滴获取率的影响较小,液桥断裂距离与液桥体积成正比变化.实验研究了平面-平面、平面-球面配置下的操作液滴动态分配进程,验证了所提出方法的可行性.     

Preparation of titanium dioxide from titania-rich slag by molten NaOH method

Preparing titanium dioxide from titania-rich slag(TiO2 73wt%) by molten NaOH method has been developed.The effects of tem-perature and reaction time on the titanium conversion were investigated.The results showed that temperature had significant influence on the titanium conversion as well as the structure of the product.About 92% of titanium in the titania-rich slag could be converted after reacting with NaOH at 500℃ for 1 h.Metatitanic acid was formed through the steps of washing treatment,acid dissolution,and hydrolysis.Well-dispersed spherical titanium dioxide particles with an average size of 0.1-0.4 μm can be obtained by calcination of metatitanic acid.In addition,the content of titanium dioxide in the product is up to 98.6wt%,which can be used as pigments after further treatment of coating and crushing.     

具有大孔-介孔结构的磷酸钛的合成及溶菌酶吸附

以混合表面活性剂十六烷基三甲基溴化铵(CTAB)和烷基酚聚氧乙烯醚(OP-10)合成了大孔-介孔结构磷酸钛,并利用X射线衍射、红外光谱、扫描电镜、透射电镜、氮气吸附等表征手段对所制备材料的结构、形貌进行表征.水/乙醇体系的样品具有大孔-介孔结构,比表面积为162 m2/g,且大孔-孔径为1~2 m.乙醇溶剂条件下样品以介孔结构存在,比表面积可以达到272 m2/g,孔容0.359 cm3/g,孔径3.7 nm.在不同的pH溶液中测试溶菌酶吸附性能,最大吸附量在等电点处(=25.94 mol/g),吸附等温线为典型的L型,表明磷酸钛是一种很好的蛋白质吸附剂.     

Preparation of PLA and PLGA nanoparticles by binary organic solvent diffusion method

The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the binary organic solvent diffusion method. The yield , particle size and size distribution of these nanoparticles were evaluated. The yield of nanoparticles prepared by this method is over 90% , and the average size of the nanoparticles is between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yield and size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that the yields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at the cloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solution and attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coincides to that near the cloud point and the optimal condition of binary organic solvents can be predicte     

钛合金的已加工表面残余应力的数值模拟

为了揭示高速切削对航空钛合金加工表面残余应力的影响，利用三维斜角切削有限元模型对钛合金Ti6Al4V的高速切削加工过程进行了模拟，获得了不同切削速度和不同切削深度下的已加工表面残余应力分布.模拟结果表明：切削速度对已加工表面残余应力具有重要影响，而切削深度对已加工表面残余应力影响较小; 已加工表面层残余应力为拉应力，沿深度方向由拉应力逐渐过渡到压应力; 3个主方向的残余应力值随切削速度的增加而增加，而随切削深度的增加无明显变化; 切削速度和切削深度对残余应力层的厚度影响都很小.     

钛丝与铸铁原位合成TiC颗粒扩散行为研究

采用铸造和热处理相结合的工艺,使钛丝与灰铸铁原位合成TiC颗粒增强铁基复合材料,并对TiC颗粒合成过程中的扩散问题进行研究.结果表明:复合材料相组成为TiC颗粒和毩Fe;在持续高温下碳原子不断向钛丝内部扩散,而钛原子几乎不向铁基体中扩散;反应进行的速度主要取决于C原子的扩散速度.     

Preparation of bentonite supported nano titanium dioxide photocatalysts by electrostatic self-assembly method

Electrostatic self-assembly method (ESAM) was used to prepare bentonite supported-nano titanium dioxide photocatalysts. The materials were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Methyl orange was used to estimate the photocatalytic activity of the materials. The effects of the calcination temperature and silane dosage on the photocatalytic activity of the samples were investigated. The experimental results show that the bentonite facilitates the formation of anatase and restrains the transformation of anatase to rutile. Part of nano-size TiO2 particles insert into the galleries of bentonite. The photocatalysts exhibit a synergistic effect of adsorption and photocatalysis on methyl orange. Photocatalysts prepared by ESAM method exhibit higher photocatalytic activity and better recycle ability than those of the traditional method.     

医用钛表面激光显微加工工艺参数的优化

为了改善医用钛的表面性能，增强植入物与骨组织之间的结合强度，采用400W Nd：YAG激光器，在压缩空气辅助条件下，对纯Ti进行激光微加工试验，并研究了激光加工工艺参数对微孔形状的影响.实验结果表明，随着激光辐照脉冲能量 、脉冲宽度、脉冲次数的增加，微孔的孔径和孔深增加.激光辐射脉冲频率增加，微孔孔径加大，而孔深基本不变.采用优化的激光微加工工艺参数，对纯钛样品进行激光显微加工， 可获得表面排布有规律的微孔，从而有利于扩大医用钛的临床应用范围.