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.     

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.     

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.     

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。     

纯钛表面微弧氧化羟基磷灰石膜的制备

应用微弧氧化技术在纯钛表面制备了含羟基磷灰石的氧化物膜。在氧化过程中,将钛试件放入含磷酸二氢钠(NaH2PO4.H2O)和乙酸钙((CH3COO)2Ca.H2O)的电解液中,用双脉冲交流电源处理。用扫描电镜(SEM)观察试件的表面形貌,用普通光学显微镜(OM)观察试件的截面形貌,用X射线衍射(XRD)分析其显微结构。结果表明,微弧氧化处理后,纯钛表面生成了内层致密外层多孔的氧化膜。     

In situ synthesis of nanostructured titania film on NiTi shape memory alloy by Fenton＇s oxidation method

Fenton＇s oxidation method was successfully used to synthesize an ideal titania film in situ on NiTi shape memory alloy（SMA） for medical applications. Characterized with scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, inductively coupled plasma mass spectrometry and electrochemical tests, it is found that the titania film produced by Fenton＇s oxidation method on NiTi SMA is nanostructured and has a Ni-free zone near its top surface, which results in a notable improvement in corrosion resistance and a remarkable decrease in leaching of harmful Ni ions from NiTi SMA in simulated body fluids. The improvement of effectiveness to corrosion resistance and the reduction in Ni release of NiTi SMA by Fenton＇s oxidation method are comparable to those by oxygen plasma immersion ion implantation reported earlier.     

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.     

NiTi合金表面电化学氧化制备Ti02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Ti02膜。通过对NiTi SMA和纯Ti在稀HC1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HC1体系,以该工艺参数进行阳极氧化处理5 min,在NiTi SMA表面制备出了完整致密的Ti02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。     

钛膜表面阳极氧化层制备及表征

为了研究钛膜表面阳极氧化层对吸附和解吸氢同位素特性的影响,需制备和表征钛膜表面阳极氧化层.设计了钛膜表面阳极氧化装置,确定了制备厚度不同的氧化层的阳极氧化工艺参数,其工艺简单、易操作;并对阳极氧化层进行了AES深度剖析和XPS化合价分析.其结果如下:在确定的工艺参数下,设计加工的阳极氧化装置能够制备出表面呈彩色的阳极氧化层,而且表面平整、光滑、均匀,与基体金属结合牢固;采用AES深度剖析确定了阳极氧化层的厚度,而且在其它条件相同时,获得阳极氧化层的厚度随着电压、H2SO4浓度和时间的增加而明显变厚的规律;采用XPS研究了阳极氧化层钛的主要价态为 4、 3和 2价,氧化层主要组成为TiO2、Ti2O3和TiO.     

NiTi形状记忆合金微弧氧化陶瓷层的制备及其工艺性研究

通过微弧氧化的方法在NiTi形状记忆合金表面制备陶瓷层.在微弧氧化之前,用常温王水对NiTi形状记忆合金进行去镍选择性腐蚀,并与工业纯钛和未经王水腐蚀的合金试样进行对比,研究了其表面形貌、相组成和微弧氧化的工艺性.研究结果表明:王水腐蚀10 min的NiTi形状记忆合金试样,微弧氧化工艺性及陶瓷层表面形貌与工业纯钛同一...     

复合活化处理镍钛合金及磷灰石层的仿生沉积

利用H2O2和NaOH溶液对近等原子比NiTi记忆合金（SMA）进行复合活化处理,并采用XRD,SEM,XPS,FTIR等研究了活化处理后NiTi SMA的表面结构及其在模拟体液（SBF）中磷灰石涂层的仿生沉积过程.结果表明：复合活化处理后NiTi SMA表面为贫Ni、富含Ti-OH的蠕虫状活性层,由结晶度较低的TiO2,钛酸纳（Na2TiO3）及少量的Ni2O3组成,在SBF中表面活性层诱导磷灰石形核及生长,短期内在镍钛基体表面获得了理想的磷灰石层.     

一种链箅机箅板抗高温氧化膜的微观分析

采用XRD,SEM和EDS等方法对一种使用寿命超过18个月箅板的抗高温氧化膜进行了微观分析和研究。结果发现,该箅板具有优异抗氧化性能,使用寿命明显高于同类产品的原因是该箅板的氧化膜的外层和内层分别是SiO2膜和Cr2O3膜,加上对氧化膜起补充作用的高温下化学性质稳定的富镍层,使得氧化膜的致密性和连续性好,氧化膜薄且嵌入在箅板基材中,使得氧化膜的粘附性好,不易剥落,保护了基材,提高了箅板的抗高温氧化性能。     

Antifouling properties of micro arc oxidation coatings containing Cu2O/ZnO nanoparticles on Ti6Al4V

Micro arc oxidation (MAO), as a new special surface treatment method, has been introduced to the marine antifouling field for titanium alloys because of the anatase and rutile TiO₂ with antibacterial effects obtained during the oxidation process. Despite this, metallic oxide antifouling additives have been added into MAO coatings to improve the antibacterial and antifouling abilities of titanium alloy. In this study, MAO coatings containing nanometer particles were obtained by adding nano Cu₂O and nano ZnO into the electrolyte. Structure, morphology, phase constitution and chemical composition of the MAO coating film were studied by SEM, XRD and EDS. The antibacterial properties of the film were evaluated by exposing the specimens to Escherichia coli and comparing the Ti-MAO and Ti-bared controls. The results showed that the MAO process on Ti6Al4V has an outstanding antibacterial property which can be further enhanced by nano Cu₂O and nano ZnO. The Ti-MAO–Cu₂O group had the best antibacterial ability. These findings indicate that by means of this process adding nanometer metallic oxide into an MAO coating film via an electrolyte is useful for enhancing the antibacterial and antifouling abilities of titanium.     

Equal channel angular extrusion of NiTi shape memory alloy tube

As a new attempt, equal channel angular extrusion (ECAE) of nickel–titanium shape memory alloy (NiTi SMA) tube was investigated by means of process experiment, finite element method (FEM) and microscopy. NiTi SMA tube with the steel core in it was inserted into the steel can during ECAE of NiTi SMA tube. Based on rigid-viscoplastic FEM, multiple coupled boundary conditions and multiple constitutive models were used for finite element simulation of ECAE of NiTi SMA tube, where the effective stress field, the effective strain field and the velocity field were obtained. Finite element simulation results are in good accordance with the experimental ones. Finite element simulation results reveal that the velocity field shows the minimum value in the corner of NiTi SMA tube, where severe shear deformation occurs. Microstructural observation results reveal that severe plastic deformation leads to a certain grain orientation as well as occurrence of substructures in the grain interior and dynamic recovery occurs during ECAE of NiTi SMA tube. ECAE of NiTi SMA tube provides a new approach to manufacturing ultrafine-grained NiTi SMA tube.     

TC4钛合金阳极氧化着色膜显色规律探讨

目的在不同电解液、电压等工艺参数下对TC4钛合金进行阳极氧化,获得彩色膜,分析探讨着色膜颜色随不同工艺参数变化的显色规律,并通过该显色规律分析着色膜显色机理。方法分别选用NaOH电解液、H3PO3电解液、Na2SiO3盐溶液对Ti6A14V钛合金进行氧化着色。通过金相显微镜、SEM、XRD、AFM和3nh色差仪等测试方法,分析氧化膜层显微组织、形貌特征、物相成分、膜层厚度与颜色变化。结果3nh色差仪测得膜层颜色值(L^*、a^*、b^*)随电压具有周期变化规律。在电压参数为120 V左右的起弧电压之前,三种电解液阳极氧化着色膜均是由非晶态的钛氧化物组成,显色规律一致,氧化膜层致密均匀,只是生长速率稍有不同。膜层显色是干涉加强光色与干涉减弱光色的互补光色的共同作用。通过钛合金氧化膜干涉光程差公式修正,推导出了薄膜厚度的理论计算公式,且AFM测试结果与理论计算得出的膜厚基本一致。随着电压继续升高,电解反应剧烈,宏观表面观察到微弧放电现象,电解过程过渡到微弧氧化阶段。结论在低电压阳极氧化阶段,TC4钛合金着色膜层是由致密均匀的非晶态钛氧化物组成,膜层生长方式是随电压均匀层状生长,显色原理主要是薄膜干涉原理。通过控制电压参数,可控制膜层厚度,继而得到理想的颜色。在Na2SiO3盐溶液中的膜层生长速率为1~1.7 nm/V。     

镍钛形状记忆合金在热压缩变形下的动态回复和动态再结晶

通过获得镍钛形状记忆合金在应变速率(0.001～1 s-1)和变形温度(600～1000℃)下的压缩真实应力—应变曲线,研究镍钛形状记忆合金在热变形下的力学行为.通过显微组织演变研究镍钛形状记忆合金的动态回复和动态再结晶,获得应变速率、变形温度和变形程度对镍钛形状记忆合金的动态回复和动态再结晶的影响规律.镍钛形状记忆合金在600℃和700℃下,动态回复和动态再结晶共存,但在其他温度下表现出完全动态再结晶.增加变形温度或降低应变速率,导致较大的等轴晶粒.变形程度对镍钛形状记忆合金的动态再结晶具有重要的影响.在镍钛形状记忆合金的动态再结晶中存在临界变形程度,当大于临界变形程度时,较大的变形程度有助于获得细小的等轴再结晶晶粒.     

Surface characterization and mechanical property of TiN/Ti-coated NiTi alloy by PIIID

A hard and adherent TiN/Ti thin film of approximately 3 μm in thickness was deposited on the surface of Ti-50.6 at.% Ni alloy by the PIIID technique. The surface composition and chemical state of the coated samples were evaluated by XPS. The XPS results indicate that titanium oxide and titanium oxynitride were present on the TiN surface. The spectra of Ti 2p, N 1s, O 1s and C 1s electrons before and after the film being sputter etched were also discussed. Scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) analyses demonstrate that an interfacial layer, containing Ti, N and Ni, was formed at the interface between the TiN and Ti coatings. Sliding wear tests show that the TiN coating significantly reduces the friction coefficient and improves wear resistance of the NiTi alloy.     

HA coating on titanium with nanotubular anodized TiO2 intermediate layer via electrochemical deposition

Hydroxyapatite（HA） coating has been prepared on titanium substrate through an electrochemical deposition approach. In order to improve the bonding strength between HA coating and Ti substrate, a well oriented and uniform titanium oxide nanotube array on the surface of titanium substrate was applied by means of anodic oxidation pre-treatment. Then the calcium hydrogen phosphate（CaHPO4·2H2O, DCPD） coating, as the precursor of hydroxyapatite coating, was electrodeposited on the anodized Ti. At the initial stage of electro-deposition, the DCPD crystals, in nanometer precipitates, are anchored in and between the tubes. With increasing the deposition time, the nanometer DCPD crystals are connected together to form a continuous coating on titanium oxide nanotube array. Finally, the DCPD coating is converted into hydroxyapatite one simply by being immersed in alkaline solution.     

Structure differences between TiO2 and phosphorus implanted TiO2 films caused by thermal treatment

The titanium oxide film has been deposited on Si wafers (110) by unbalance reactive magnetron sputtering and modified by phosphorus ion implantation and succeeding vacuum annealing. The structural, states of surface chemistry and surface morphology of the films have been investigated by X-ray diffraction (XRD), X-ray photoelectric spectroscopy (XPS), atomic force microscope (AFM) and Scanning Electron Microscope (SEM), respectively. The results of XRD show rutile structure of as-deposited film, which is not changed by phosphorus implantation and vacuum annealing. However, a slightly shift of the peaks position to higher degree and the half width increases after ion implanted and vacuum annealing represent that the variety of the structure film caused by these treatments. The surface roughness is inclined to increase with the rising of annealing temperature for both undoped and P doped titanium oxide films. The surface chemistry presents significant difference between undoped and phosphorus doped films after a vacuum annealing, it may be attributed to the different evolvement of the surface defects existing in the film, which may be considered as an important influencing factor in the blood compatibility of the titanium oxide film.     

退火对NiTi合金材料表面氧离子注入所产生残余应力影响的试验研究

离子体与NiTi合金材料表面相互作用可以改变材料表面的特性,在工程技术、生物医学等方面有很高的应用价值.氧离子作为注入剂注入后,在NiTi合金材料表面形成Ti02膜,薄膜与基体材料之间的晶格错配,热力学等参数失配引起薄膜与基体间的界面上出现残余应力.文中用云纹干涉与钻孔法相结合测量了NiTi合金表面氧离子注入后所产生的残余应力,探讨了退火处理对残余应力的影响.