羟基磷灰石/Ti-13Nb-13Zr复合材料的组织性能与细胞相容性评价

为了改善Ti-13Nb-13Zr医用钛合金的生物活性与细胞相容性,利用放电等离子烧结(SPS)技术制备了Ti-13Nb-13Zr合金和羟基磷灰石(HA)含量5wt%的5HA/Ti-13Nb-13Zr复合材料并进行退火处理,研究了两种材料的显微组织、力学性能、表面润湿性、体外矿化行为及细胞增殖与凋亡等生物学性能。结果表明：合金主要由β-Ti和α-Ti相组成,复合材料由β-Ti、α-Ti、HA相及少量陶瓷反应相(Ca₃(PO₄)₂、CaZrO₃、CaO)组成,退火后部分初生α-Ti转变为β-Ti且组织更均匀,HA的加入会使得晶粒细化;退火后两种材料抗压强度、屈服强度、屈强比和弹性模量均略微下降;HA的加入提高了复合材料亲水性、类骨磷灰石形成能力、细胞增殖率并降低了细胞凋亡率;综合分析,退火后的5HA/Ti-13Nb-13Zr复合材料抗压强度、屈服强度和弹性模量分别为(1 744±9) MPa、(1 493±12) MPa和(43±1.6) GPa,具有优异的类骨磷灰石形成能力,同时细胞增殖率达到99.1...     

Ti-35Nb-7Zr/10CPP生物复合材料微观组织与性能研究

添加了占钛合金基体10%(质量分数)的焦磷酸钙(CPP)生物活性陶瓷粉末,利用放电等离子烧结(SPS)技术制备了Ti-35Nb-7Zr/10CPP生物复合材料,研究了其物相组成、微观组织形貌、元素分布、力学性能以及生物活性等。结果表明,该复合材料主要由β-Ti相基体、少量的α-Ti相及金属-陶瓷相(CaO、Ti2O、CaTiO3、CaZrO3、TxPy)组成;复合材料具有较低的压缩弹性模量(46 GPa)和较高的抗压强度(1 434 MPa),显示了良好的力学相容性;与Ti-35Nb-7Zr合金相比,复合材料在人工模拟体液(SBF)浸泡7d后表面生成了大量的类骨磷灰石层,显示出良好的生物活性。     

烧结温度对焦磷酸钙/Ti-35Nb-7Zr复合材料微观组织及力学性能的影响

为改善β型Ti-Nb-Zr合金的生物活性,添加20wt%的焦磷酸钙(CPP)生物陶瓷,利用放电等离子烧结技术制备20CPP/Ti-35Nb-7Zr生物复合材料。借助XRD、SEM及力学测试方法等研究不同烧结温度(1 000~1 200℃)下复合材料的微观组织及力学性能,揭示其组织演变对力学性能的影响机制。结果表明:20CPP/Ti-35Nb-7Zr复合材料主要由β-Ti相基体、少量残留α-Ti相及金属-陶瓷相(CaTiO_3、Ti_2O、CaO、CaZrO_3和TixPy)组成;随着烧结温度升高,复合材料中β-Ti相和金属-陶瓷相逐渐增多;金属与陶瓷之间的剧烈反应导致金属-陶瓷相的形态结构发生变化,复合材料中金属-陶瓷相从颗粒状析出物演变成连续网状组织,起到割裂基体的作用。20CPP/Ti-35Nb-7Zr复合材料的压缩弹性模量和抗压强度随着烧结温度的升高而增大,其中压缩弹性模量从64.0GPa增加至71.4GPa,金属-陶瓷相形态结构变化起主导作用。因此,控制20CPP/Ti-Nb-Zr复合材料中金属-陶瓷相的形态结构将有利于改善其力学性能。     

表面多孔Ti-羟基磷灰石/Ti-Ag生物梯度复合材料的制备与性能

采用放电等离子烧结技术制备表面多孔Ti-羟基磷灰石（HA）/Ti-Ag生物梯度复合材料,研究了不同HA含量对复合材料微观结构、界面结合、表面孔隙特征、力学性能及体外生物活性的影响及机制。结果表明,表面多孔Ti-HA/Ti-Ag复合材料中间基体合金主要由α-Ti和Ti₂Ag相组成,表面多孔层主要由α-Ti和HA相组成,同时还存在少量CaO、CaTiO₃、Ti₅P₃等反应相;表面多孔Ti-HA/Ti-Ag复合材料中间基体与表面多孔层形成稳定的冶金结合,但随着HA含量增加,反应相增多,界面结合变差,表面孔隙率和平均孔径呈增大趋势,导致平均抗压强度减小且弹性模量降低,因此过高的HA含量会导致材料力学性能下降;体外生物活性实验表明,表面多孔Ti-HA/Ti-Ag复合材料在人工模拟体液中浸泡7天后表面生成大量类骨磷灰石层,并且随着HA含量的增大,磷灰石形成能力明显增强。      

造孔剂对新型医用多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金组织性能的影响

合金多孔化是有效降低材料弹性模量的方式之一,采用添加造孔剂的元素粉末冶金法制备了新型医用多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金,通过扫描电镜、阿基米德法、X射线衍射和压缩力学性能测试的方法研究了不同造孔剂用量和粒径尺寸对合金形貌特征、孔隙率、物相组成及力学性能的影响规律。结果表明:该方法制备所得多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金为近β型钛合金;随着造孔剂用量增加,平均孔径无变化,孔隙率呈线性增长,弹性模量和抗压强度减小,其中弹性模量的变化满足线性关系;随着造孔剂粒径尺寸增加,平均孔径增大而孔隙率基本不变,抗压强度和弹性模量减小;添加20%(质量分数)粒径尺寸为125~200μm的NH4HCO3造孔剂制备多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金,于1300℃烧结4h孔隙率达到38.9%并含有贯穿孔结构,抗压强度达到405 MPa,而弹性模量为9.19GPa,能满足医用植入材料的要求。     

多孔ZnO/羟基磷灰石生物复合材料的制备与性能

利用放电等离子烧结技术制备多孔ZnO/羟基磷灰石（HA）生物复合材料,研究不同纳米ZnO含量对ZnO/HA复合材料微观结构、孔隙特征、力学性能、矿化和降解性能的影响。结果表明:烧结后ZnO/HA复合材料主要由HA相和ZnO相组成;随着ZnO含量提高,多孔ZnO/HA复合材料孔隙率缓慢增大,抗压强度略有减小,弹性模量变化不大;多孔ZnO/HA复合材料的孔隙率>40%,孔径在50～500 μm之间,抗压强度>148 MPa,弹性模量为6.5 GPa左右,能够满足骨修复材料的要求;模拟人工体液中矿化和降解实验表明,多孔ZnO/HA复合材料浸泡7天后表面开始形成大量类骨磷灰石层,且随着ZnO含量增加,磷灰石形成能力明显增强而降解速率加快。      

表面多孔NiTi-羟基磷灰石/NiTi生物复合材料的制备与性能

利用放电等离子烧结技术制备了表面多孔NiTi-羟基磷灰石(HA)/NiTi生物复合材料,研究了烧结温度对复合材料宏观形貌、微观结构、表面孔隙特征、力学性能及体外生物活性的影响。结果表明:随着烧结温度从800℃提高到950℃,NiTi-HA/NiTi复合材料由复杂的Ti、Ni、Ti_2Ni、Ni_3Ti、HA混合相逐渐转变为单一的NiTi+HA相,内外层界面形成稳定的冶金结合且表面孔隙率与平均孔径呈缓慢减小趋势;同时抗压强度显著提高而弹性模量变化不明显。与传统NiTi、多孔NiTi及多孔NiTi-HA材料相比,950℃温度下制备的NiTi-HA/NiTi复合材料不仅具有良好的界面结合和表面孔隙特征(孔隙率45.6%、平均孔径393μm)、较高的抗压强度(1 301MPa)、较低的弹性模量(10.2GPa)以及优异的超弹性行为(超弹性恢复应变4%)的最佳匹配,而且还具有良好的体外生物活性。     

羟基磷灰石晶须/聚左旋乳酸复合材料的制备及性能

研究了两种不同形貌的羟基磷灰石(粉体和晶须)以及热压温度对羟基磷灰石/聚左旋乳酸(HA/PLLA)复合材料机械性能的影响,并优化了两者的质量配比。通过扫描电镜(SEM)、万能试验机和体外浸泡实验对复合材料的显微结构、抗压强度和生物活性进行表征。结果显示,在PLLA基质中HA晶须具有更好的增强效果,当HA晶须与PLLA质量比为1∶1,热压温度为170℃时,复合材料具有最大的抗压强度98MPa,比对应粉体增强复合材料的抗压强度提高了53%。体外浸泡实验说明了羟基磷灰石晶须/聚左旋乳酸(HA-w/PLLA)复合材料具有良好的生物活性。     

高HA含量的PEKK/HA复合材料的制备及其力学相容性

本研究合成了一种由高分子聚醚酮酮(PEKK)和羟基磷灰石(HA)组成的复合材料,其中部分HA被PEKK包裹,制得的PEKK/HA复合材料中HA的质量分数达到50%,与人体骨骼中HA的含量相近。该复合材料中HA在PEKK中分布均匀,无明显的相分离现象,模量为14.5GPa,硬度为0.5GPa,断裂屈服强度为167.65MPa,此三项力学性能均与人体骨骼的性能接近。     

新型钛基复合材料的制备及生物学评价

以羟基磷灰石(HA)和钛粉(Ti)为原料,在真空下1 200℃烧结3h,当HA所占质量分数分别为40%,15%和5%时,得到的烧结体抗压强度分别为15.50,57.63和188.82MPa。XRD分析显示,除钛以外,烧结体中出现了Ti_3O、Ti_3P及CaO等相,表明烧结体为新型复合材料。将HA添加量为5%烧结后所得的复合材料浸泡在SBF溶液中7d后,该复合材料表面被球状HA覆盖。实验结果表明该材料具有优异的生物活性及力学性能。     

Development and characterization of β-type Ti-Zr-Nb-Sn dental implant materials

To develop new materials of proper elastic modulus and biocompatibility for dental implants, Ti-2Zr-xNb-xSn (x = 0, 0.1, 0.2, 0.3) and Ti-2Zr-xNb-xMo (x = 0, 0.1, 0.2, 0.3) alloys were designed and fabricated. Effects of alloying elements on properties and the feasibility of application in dentistry are analyzed. It is indicated that Nb, Sn and Mo obviously influence the phase compositions of Ti-2Zr-based biological alloys. With the increase of alloying element content, all the alloys tend to form a single β-Ti phase. Ti-2Zr-xNb-xSn alloys exhibit better mechanical properties and corrosion resistance than the Ti-2Zr-xNb-xMo alloys. The Ti-2Zr-0.1Nb-0.1Sn alloy has proper elastic modulus (14.72 GPa) (which is very close to the natural bones), excellent corrosion resistance and comprehensive mechanical properties, and is considered as ideal candidate for implant materials.     

XPS characterization of surface modified titanium alloys for use as biomaterials

Three different Ti alloys of biomedical interest have been studied by means of X-ray photoelectron spectroscopy (XPS) to determine their surface chemical composition in both as-received condition and after oxidation at 750 °C in air for different times. Compositions of the investigated alloys were, in wt.%, Ti-7Nb-6Al, Ti-13Nb-13Zr and Ti-15Zr-4Nb. XPS analyses showed a behaviour of the Ti-7Nb-6Al alloy different from that of the two TiNbZr alloys, evidencing the role of the chemical composition of the alloys on the oxidation mechanisms. The oxidation process generates an aluminium-oxide rich surface on the Ti-7Nb-6Al, while in the case of the TiNbZr alloys a titanium-oxide rich layer is formed. The effect of the heat treatment on the contribution of the minority elements at the surface is also discussed.     

Hydroxyapatite coating on the Ti-35Nb-xZr alloy by electron beam-physical vapor deposition

The aim of this study was to investigate the hydroxyapatite coating on the Ti-35Nb-xZr alloy by electron beam-physical vapor deposition. The Ti-35Nb-xZr ternary alloys contained from 3 wt.% to 10 wt.% Zr content were manufactured by arc melting furnace. Hydroxyapatite (HA) coatings were prepared by electron-beam physical vapor deposition (EB-PVD) method, and crystallization treatment was performed in Ar atmosphere at 300 and 500 °C for 1 h. The coated surface morphology of Ti-35Nb-xZr alloy was examined by FE-SEM, EDX and XRD, respectively. In order to evaluate the corrosion behavior, the tests were performed by potentiodynamic, cyclic polarization and AC impedance test. All the electrochemical data were obtained using a potentiostat. The Ti-35Nb-xZr alloys exhibited equiaxed structure with β phase, the peak of β phase increased with Zr contents. The hardness and elastic modulus of Ti-35Nb-xZr alloys decreased as Zr content increased. The HA coated layer was approximately 150 nm and Ca/P ratio of HA coated surface after heat treatment at 500 °C was around 1.67. The HA thin film consisted of small droplets with spherical shape by crystallization. From the anodic polarization curves, HA coated and heat treated Ti-35Nb-10Zr alloy showed higher corrosion potential than other samples. HA coated film on the Ti-35Nb-10Zr alloy can be shown high polarization resistance by crystallization.     

In vitro Biological Effects of Ti2448 Alloy Modified by Micro-arc Oxidation and Alkali Heatment

The purpose of this study was to test the hypothesis that the combination of micro-arc oxidation and alkali heatment (MAH) would improve the cytocompatibility of a newly designed Ti-24Nb-4Zr-8Sn alloy.In this study,commercially pure titanium (cp Ti) and Ti-24Nb-4Zr-8Sn were used.Surface modification of Ti-24Nb4Zr-8Sn by a two-step treatment of micro-arc oxidation (MAO) and alkali heatment was reported.Surface characterizations were performed by scanning electron microscopy (SEM),thin film X-ray diffraction (TF-XRD) and X-ray photoelectron spectroscopy (XPS).The MAH layer consisted of finer crystals and possessed a higher degree of crystallity and stability than the MAO layer.A biocompatibility study on treated and untreated Ti24Nb-4Zr-8Sn in comparison with cp Ti was carried out to investigate the effect of the different surfaces on the bone integration property in vitro.The cellular assays revealed that the MAO and MAH layer favored the initial adhesion of MC3T3-E1 cells and that the growth rate of MC3T3-E1 cells on MAH layer was significantly higher than that on the conventional MAO-treated layer after 3-day and 5-day incubation,demonstrating the greater potential of the hybrid treatment of micro-arc oxidation followed with alkali heatment as a novel surface modification method for implanting materials.     

Effects of molybdenum content on the structure and mechanical properties of as-cast Ti-10Zr-based alloys for biomedical applications

The effects of molybdenum on the structure and mechanical properties of a Ti-10Zr-based system were studied with an emphasis on improving the strength/modulus ratio. Commercially pure titanium (c.p. Ti) was used as a control. As-cast Ti-10Zr and a series of Ti-10Zr-xMo (x = 1, 3, 5, 7.5, 10, 12.5, 15, 17.5 and 20 wt.%) alloys prepared using a commercial arc-melting vacuum pressure casting system were investigated. X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The experimental results indicated that these alloys had different structures and mechanical properties when various amounts of Mo were added. The as-cast Ti-10Zr has a hexagonal α′ phase, and when 1 wt.% Mo was introduced into the Ti-10Zr alloy, the structure remained essentially unchanged. However, with 3 or 5 wt.%, the martensitic α″ structure was found. When increased to 7.5 wt.% or greater, retention of the metastable β phase began. The ω phase was observed only in the Ti-10Zr-7.5Mo alloy. Among all Ti-10Zr-xMo alloys, the α″-phase Ti-10Zr-5Mo alloy had the lowest elastic modulus. It is noteworthy that all the Ti-10Zr and Ti-10Zr-xMo alloys had good ductility. In addition, the Ti-10Zr-5Mo and Ti-10Zr-12.5Mo alloys exhibited higher bending strength/modulus ratios at 20.1 and 20.4, respectively. Furthermore, the elastically recoverable angles of these two alloys (26.4° and 24.6°, respectively) were much greater than those of c.p. Ti (2.7°). Given the importance of these properties for implant materials, the low modulus, excellent elastic recovery capability and high strength/modulus ratio of α″ phase Ti-10Zr-5Mo and β phase Ti-10Zr-12.5Mo alloys appear to make them promising candidates.     

A novel biomedical titanium alloy with high antibacterial property and low elastic modulus

β-type titanium alloys have attracted much attention as implant materials because of their low elastic modulus and high strength,which is closer to human bones and can avoid the problem of stress fielding and extend the lifetime of prosthetics.However,other issues,such as the infection or inflammation postimplantation,still trouble the titanium alloy's clinical application.In this paper,we developed a novel near β-titanium alloy (Ti-13Nb-13Zr-13Ag,TNZA) with low elastic modulus and strong antibacterial ability by the addition of Ag element followed by proper microstructure controlling,which could reduce the stress shielding and bacterial infections simultaneously.The microstructure,mechanical properties,corrosion resistance,antibacterial properties and cell toxicity were studied using SEM,electrochemical testing,mechanical test and cell tests.The results have demonstrated that TNZA alloy exhibited an elastic modulus of 75-87 GPa and a strong antibacterial ability (up to 98 ％ reduction) and good biocompatibility.Moreover,it was also shown that this alloy's corrosion resistance was better than that of Ti-13Nb-13Zr.All the results suggested that Ti-13Nb-13Zr-13Ag might be a competitive biomedical titanium alloy.     

Phenomena of nanotube nucleation and growth on new ternary titanium alloys

Ti-30Nb-xZr and Ti-30Ta-xNb alloys have been investigated using various methods of surface nanotube formation. Ternary Ti-30Nb-xZr (x = 3 and 15 wt%) and Ti-30Ta-xNb (x = 3 and 15 wt%) alloys were prepared by using high-purity sponge Ti (Grade 4, G&S Titanium, USA), Ta, Zr and Nb spheres. The two groups of ternary Ti alloys were prepared using a vacuum arc melting furnace. Nanotube formation was carried out with a conventional three-electrode configuration with the Ti alloy specimen, a platinum counterelectrode, and a saturated calomel (SCE) reference electrode. Experiments were performed in 1 M H3PO4 with small additions of NaF (0.1-0.8 wt%), using a potentiostat. Nanotubes formed on the surfaces of the two ternary Ti alloys were examined by field emission scanning electron microscopy, EDS and XRD. The Ti-30Ta-xZr alloys had microstructure with entirely needle-like constituents; the thickness of the needle-like alpha-phase increased as the Zr content increased. The Ti-30Nb-xZr alloys had equiaxed microstructures of the beta-phase, and increasing amounts of the needle-like alpha phase appeared at the grain boundaries of the beta-phase as the Zr content increased. The nanotubes were nucleated and grew mainly on the beta phase for the Ti-30Ta-3Zr and Ti-30Nb-3Zr alloys, which had nanotubes with uniform shape, but the nanotubes were nucleated at the alpha phase for the Ti-30Ta-15Zr and Ti-30Nb-15Zr alloys, which had nanotubes with irregular shape and diameters of two sizes. The diameter and depth of the nanotubes could be controlled, depending upon the alloy composition and composition of the surface oxide films (TiO2, Nb2O5, Ta2O5, and ZrO2). It is concluded that this research that selection of the appropriate alloying element can allow significant control of the nanotopography of these Ti alloy surfaces and that it is possible to control the surface nanotube size to promote long-term osseointegration for clinical dental or orthopedic use.     

Study of the in vitro corrosion behavior and biocompatibility of Zr-2.5Nb and Zr-1.5Nb-1Ta (at%) crystalline alloys

The in vitro corrosion behavior and biocompatibility of two Zr alloys, Zr-2.5Nb, employed for the manufacture of CANDU reactor pressure tubes, and Zr-1.5Nb-1Ta (at%), for use as implant materials have been assessed and compared with those of Grade 2 Ti, which is known to be a highly compatible metallic biomaterial. The in vitro corrosion resistance was investigated by open circuit potential and electrochemical impedance spectroscopy (EIS) measurements, as a function of exposure time to an artificial physiological environment (Ringer’s solution). Open circuit potential values indicated that both the Zr alloys and Grade 2 Ti undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface, in the aggressive environment. It also indicated that the tendency for the formation of a spontaneous oxide is greater for the Zr-1.5Nb-1Ta alloy and that this oxide has better corrosion protection characteristics than the ones formed on Grade 2 Ti or on the Zr-2.5Nb alloy. EIS study showed high impedance values for all samples, increasing with exposure time, indicating an improvement in corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film presents on the metals surface, improving their resistance with exposure time, presenting the highest values to the Zr-1.5Nb-1Ta alloy. For the biocompatibility analysis human osteosarcoma cell line (Saos-2) and human primary bone marrow stromal cells (BMSC) were used. Biocompatibility tests showed that Saos-2 cells grow rapidly, independently of the surface, due to reduced dependency from matrix deposition and microenvironment recognition. BMSC instead display a reduced proliferation, possibly caused by a reduced crosstalk with the metal surface microenvironment. However, once the substrate has been colonized, BMSC seem to respond properly to osteoinduction stimuli, thus supporting a substantial equivalence in the biocompatibility among the Zr alloys and Grade 2 titanium. In summary, high in vitro corrosion resistance together with satisfactory biocompatibility make the Zr-2.5Nb and Zr-1.5Nb-1Ta crystalline alloys promising biomaterials for surgical implants.