纳米SrFe12O19磁性能对NiTi合金、316L不锈钢血液相容性的影响

用溶胶凝胶法制备纳米SrFe12O19磁性粉末,并用磁强计检测SrFe12O19粉末的磁性能,在NiTi合金、316L不锈钢表面用溶胶凝胶法制备含SrFe12O19磁性粉末的TiO2薄膜,并用X射线衍射仪分析薄膜成分.测试不同层数薄膜的微磁场强度,并对这些薄膜测定动态凝血时间和溶血率,以研究不同的表面微磁场强度对材料血液相容性的影响.结果表明:材料表面的微磁场强度愈高,材料血液相容性愈好.     

表面肝素改性TLM钛合金的血液相容性评价

在新型近β钛合金TLM(Ti-3Zr2Sn-3Mo-25Nb)表面用溶胶-凝胶法镀上一层TiO2薄膜,再将薄膜依次用羟基化溶液和胺基化溶液处理以在薄膜表面引入活性OH-和NH2-,然后通过该活性官能团将肝素共价键接在薄膜表面.利用XRD、SEM和EDS研究了TiO2薄膜的相结构和表面特性:通过测定材料表面的接触角、溶血率和血小板黏附行为对肝素化TLM合金的血液相容性进行分析、评价.结果表明,表面肝素化处理后TLM合金的血液相容性得到了明显的改善.     

AZ91D压铸镁合金激光局部重熔区气孔的形成机制

采用扫描电镜(SEM)、X光电子能谱分析仪(XPS)等分析手段,研究了NiTi合金表面绝缘膜的结构及成分,从而探讨非阀金属NiTi合金表面微弧氧化陶瓷膜层的形成机制.结果表明,NiTi合金微弧氧化过程中的电流密度-时间曲线与纯钛形状基本一致,也可分为3个阶段,但其最大的电流密度为后者的13倍;NiTi合金表面的绝缘膜主要是通过电化学沉积形成的Al2O3及少量的TiO2、Ni2O3和磷酸盐薄膜,这一绝缘膜就相当于阀金属的阳极氧化膜,为NiTi合金进行微弧氧化处理提供了前提条件;NiTi合金表面的陶瓷膜层主要来源于电解液中的铝酸根离子和少量的基体Ni和Ti(包括固态的和溶解于电解液中离子态的),经反复的放电、熔融、喷射、冷却、凝固,发生一系列的电化学、等离子体化学和热化学反应最终形成表面粗糙多孔陶瓷膜层.     

医用NiTi合金表面改性技术研究进展

近等原子比的NiTi合金以其独有的形状记忆效应和超弹性在医疗领域具有广泛的应用,但近年来研究表明,镍离子会使人体发生中毒反应,甚至致癌,这一因素制约了它在生物医用材料领域的使用。为了抑制镍离子的释放,通过对NiTi合金表面改性,制备一层氧化膜,可有效提高使用的安全性。文章全面阐述了近几年来NiTi合金表面改性的研究进展,提出了对多孔医用NiTi合金表面TiO2改性的发展前景。     

NiTi合金基TiN薄膜的血液相容性和耐腐蚀性研究

采用电弧离子镀法在NiTi形状记忆合金表面制备了TiN薄膜，利用X射线衍射、扫描电子显微镜和原子力显微镜研究了TiN薄膜的相组成及表面特性；在生物体外，研究比较了镀膜和未镀膜的NiTi合金的血液相容性和耐腐蚀性。结果表明：TiN薄膜提高了NiTi合金的血液相容性，并使Ni离子的释放率约降低了1个数量级，有效地提高了NiTi合金的耐腐蚀性。薄膜越厚性能提高的效果越显著。     

TiO2／NiTi合金中Ni的扩散模型研究

对TiO2/NiTi合金中Ni的扩散行为进行了探讨,建立了半无界空间的Ni原子恒定浓度扩散数学模型,定量的推导出了Ni通过TiO2膜的数学表达式.根据医学标准Ni在人体允许的最大含量,可以预测NiTi合金植入人体中的使用寿命.     

NiTi合金激光熔凝处理及其生物腐蚀性能研究

目的 通过对NiTi合金表面进行激光熔凝处理,从而提高NiTi合金的耐腐蚀性能。方法 利用紫外激光器对NiTi合金进行表面熔凝处理,借助扫描电子显微镜(SEM)、光学显微镜(OM)、能量色散X射线光谱仪(EDX)和X射线衍射仪(XRD)等技术手段,研究了激光熔凝处理前后NiTi合金的表面显微组织、成分和相结构。测试了激光熔凝处理前后NiTi合金表面与模拟体液(SBF)的接触角、熔凝层的显微硬度等表面性能。通过全浸腐蚀试验和电化学测试,研究了熔凝层在SBF溶液中的生物腐蚀性能,并分析了腐蚀机理。结果 NiTi合金经过激光熔凝处理后,在合金的表层形成了厚度为90~150 μm的熔凝层,熔凝层主要由TiO2、β相以及少量的TiO相组成。合金表面的平均显微硬度提高了153~279HV,合金的表面接触角增大,由亲水性转为疏水性。相较于未处理的样品,熔凝处理后的样品在SBF溶液中的腐蚀电位分别正移了435 mV和413 mV,腐蚀电流密度分别下降了83%、62%左右。熔凝处理后的样品在SBF溶液浸泡168 h后,SBF溶液中的Ni²⁺浓度下降了约1/3。结论 以适当的激光加工参数对NiTi合金进行激光熔凝处理,可在NiTi合金表面形成致密的氧化膜,这层氧化膜和熔凝层可以有效地抑制NiTi合金在SBF溶液中的点腐蚀行为。     

氮掺杂二氧化钛薄膜的制备与光催化性能

采用溶胶-凝胶法制备了氮掺杂改性的TiO2薄膜,用表面形貌仪、扫描电镜和光电子能谱仪等分析薄膜的厚度、表面形貌和成分,研究了薄膜对亚甲基蓝的光催化降解速率.结果表明,通过加入尿素实现了氮离子在TiO2晶格间的间隙掺杂和替位掺杂.薄膜厚度在50～200 nm之间,表面平整.氮离子掺杂使TiO2薄膜的光催化活性大大提高,当氮掺杂TiO2薄膜中N/Ti原子比为0.015时,单层氮掺杂TiO2薄膜降解亚甲基蓝一半所需要的时间为2.5 h.     

NiTi合金表面电化学氧化制备TiO2膜

采用恒电流阳极氧化法在NiTi形状记忆合金(SMA)表面制备完整致密且耐腐蚀的TiO2膜.通过对NiTi SMA和纯Ti在稀HCl中的动电位阳极极化曲线的分析,得到了选择性脱Ni阳极氧化电流密度工艺参数.试验采用稀HCl体系,以该工艺参数进行阳极氧化处理5min,在NiTi SMA表面制备出了完整致密的TiO2膜,并进行了其表面的SEM、XRD、XPS分析和NiTi SMA表面处理前后在模拟唾液fusayama中的对比腐蚀试验测试.结果表明:经阳极氧化处理的NiTi SMA表面形成了十几纳米厚的TiO2膜,且其耐蚀性有明显的提高.     

医用Ti3Zr2Sn3Mo25Nb钛合金表面自组装活性抗凝血复合涂层的构建及其血液相容性

为改善新型近β钛合金Ti3Zr2Sn3Mo25Nb(TLM)的抗凝血性能和血液相容性,通过溶胶-凝胶和表面官能化技术在TLM合金表面制备出一层活性TiO2薄膜,再利用自组装技术在TiO2薄膜表面构建一个肝素-白蛋白多层功能复合涂层。利用Raman光谱分析改性处理后TLM合金表面涂层的相组成,借助SEM、AFM研究了复合涂层的表面形貌和微观特征,通过溶血率测试、血小板粘附试验对TLM合金表面改性前后的血液相容性进行评估。结果表明,经表面肝素-白蛋白复合涂层修饰处理后,TLM合金的溶血率显著降低,表面粘附的血小板数量明显减少且激活反应轻微,即TLM合金的抗凝血性能和血液相容性均得到了明显改善。     

退火温度及TiO_2结构对羟基磷灰石的沉积诱导作用

采用阳极氧化法在钛金属表面制备TiO2薄膜,将表面改性的钛金属在过饱和钙化溶液中浸泡,在其表面沉积羟基磷灰石,研究了退火处理温度对TiO2薄膜晶型转变的影响以及TiO2的晶型结构对羟基磷灰石的诱导沉积作用。研究表明,300℃退火处理,TiO2薄膜为板钛矿相,500℃退火处理转变为锐钛矿相,高于500℃退火处理,锐钛矿相开始向金红石相转变。其中锐钛矿相的TiO2对羟基磷灰石的沉积具有最好诱导作用,沉积物分布均匀,板钛矿相对羟基磷灰石的诱导作用最差,所形成的沉积层是由片状的羟基磷灰石围成的多孔结构。     

In situ formation of titania film on NiTi alloy treated with hydrogen peroxide solution at low temperature

Chemically polished NiTi shape memory alloy（SMA） substrate was treated with a boiling aqueous solution containing hydrogen peroxide to form titania film in situ at low temperature. The surface characterizations of titania film on NiTi substrate were investigated by scanning electron microscopy, X-ray diffractometry and X-ray photoelectron spectroscopy. The results show that titania film is successfully fabricated in situ on NiTi SMA by this surface oxidation method. It is mainly composed of rutile and anatase, whose surface compositions and morphologies are sensitive to H2O2 content. In situ formation mechanism of titania film on NiTi substrate was discussed based on the experimental results.     

磁控溅射Zr-Ti薄膜的组织结构与血液相容性

通过直流平衡磁控溅射法在NiTiSMA表面生成Zr-Ti膜,用SEM、XRD和XPS分析证实制备的Zr-Ti膜呈现晶带T型结构,组织保持了细小致密的纤维状特征,与基底结合良好,并且出现了少量生物惰性ZrO2和TiO2陶瓷相。通过测定溶血率研究血小板黏附行为,评估血液相容性。结果表明,与NiTi基底相比,Zr-Ti膜的溶血率更低,表面黏附的血小板数量减少,能够改善NiTiSMA基底的血液相容性。最后,对磁控溅射沉积Zr-Ti膜的成膜机理进行了探讨。     

In vitro biocompatibility of titanium-nickel alloy with titanium oxide film by H2O2 oxidation

Titanium oxide film with a graded interface to NiTi matrix was synthesized in situ on NiTi shape memory alloy（SMA） by oxidation in H2O2 solution. In vitro studies including contact angle measurement, hemolysis, MTT cytotoxicity and cell morphology tests were employed to investigate the biocompatibility of the H2O2-oxidized NiTi SMAs with this titanium oxide film. The results reveal that wettability, blood compatibility and fibroblasts compatibility of NiTi SMA are improved by the coating of titanium oxide film through H2O2 oxidation treatment.     

Surface treatment of NiTi shape memory alloy by modified advanced oxidation process

A modified advanced oxidation process(AOP) utilizing a UV/electrochemically-generated peroxide system was used to fabricate titania films on chemically polished NiTi shape memory alloy(SMA). The microstructure and biomedical properties of the film were characterized by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), inductively-coupled plasma mass spectrometry(ICPMS), hemolysis analysis, and blood platelet adhesion test. It is found that the modified AOP has a high processing effectiveness and can result in the formation of a dense titania film with a Ni-free zone near its top surface. In comparison, Ni can still be detected on the outer NiTi surface by the conventional AOP using the UV/H2O2 system. The depth profiles of O, Ni, Ti show that the film possesses a smooth graded interface structure next to the NiTi substrate and this structure enhances the mechanical stability of titania film. The titania film can dramatically reduce toxic Ni ion release and also improve the hemolysis resistance and thromboresistance of biomedical NiTi SMA.     

A Composite Photoanode Based on P25/TiO_2 Nanotube Arrays/Flower-Like TiO_2for High-Efficiency Dye-Sensitized Solar Cells

In this work,a three-layer TiO_2 composite film consisting of flower-like TiO_2 (Flo-TiO_2 )as overlayer,TiO_2 nanotube arrays as interlayer and TiO_2 nanoparticle(P25)as underlayer was fabricated as the photoelectrode of dyesensitized solar cells(DSSCs).Due to the introduction of Flo-TiO_2 ,the three-layer composite film has strong lightscattering ability.Then,we have investigated and compared the photoelectric conversion properties of DSSCs based on three-layer structure(P25/TNT arrays/Flo-TiO_2 )photoelectrode and double-layer film(P25/TNT arrays)photoelectrode.It is found that DSSCs based on three-layer structure exhibit a high power conversion efficiency of 6.48%compared with the DSSCs composed of double-layer film(5.11%).     

镍钛合金光催化高级氧化表面改性与生物相容性

在UV/H2O2光催化体系中,通过高级氧化法在NiTi SMA表面生成贫Ni的Ti氧化膜.通过亲水性试验、血小板黏附试验以及MTT细胞毒性试验对改性后试样的生物相容性进行了系统的评价,研究发现改性后试样的亲水性得到明显改善.表面血小板黏附数量减少,变形和团聚现象得到抑制,形成血栓的可能性降低,血液相容性得到提高.改性后试样的细胞相对增殖率(RGR)高于化学抛光的试样,试样周围细胞分裂增生良好,与材料边缘结合自然,改性处理同样提高了试样的细胞相容性.结果表明光催化高级氧化是提高NiTi SMA生物相容性的一种有效方法.     

High photocatalytic activity of Cu_2O/TiO_2/Pt composite films prepared by magnetron sputtering

Cu_2O/TiO_2/Pt three-layer films were deposited on glass substrates using magnetron sputtering method.The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), ultravioletvisible spectroscopy(UV-Vis) and photoluminescence spectroscopy(PL). The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange(MO) aqueous solution under visible light irradiation. The results indicate that the Cu_2O/TiO_2/Pt composite films are made up of three layers which are Pt layer,anatase-TiO_2 layer and Cu_2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu_2O/TiO_2/Pt three-layer film is much higher than that of the Cu_2O/TiO_2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.     

微弧氧化法原位生长TiO_2光催化薄膜及其复合技术

介绍了利用微弧氧化技术制备TiO2光催化薄膜的工艺过程、形成机理、影响因素,以及膜层结构与性能之间的关系等。提出在微弧氧化工艺制备TiO2光催化薄膜的过程中,通过复合半导体、金属掺杂和非金属掺杂,可以有效地提高其光催化性能。