ZrO2/hydroxyapatite coating on titanium by electrolytic deposition

In this study, hydroxyapatite (HA) was coated on a titanium (Ti) substrate over a ZrO(2) layer by the electrolytic deposition method, this double layer coating was then compared with a single layer coating of HA. The HA layer was used to increase the bioactivity and osteoconductivity of the Ti substrate, and the ZrO(2) layer was intended to improve the bonding strength between the HA layer and Ti substrate, and to prevent the corrosion of the Ti substrate. The electrolytic deposition formed an HA layer with a thicknesses of approximately 20 mum, which adhered tightly to the Ti substrate. The bonding strength of the HA/ZrO(2) double layer coating on Ti was markedly improved when compared to that of the HA single coating on Ti. The improvement in bonding strength with the use of a ZrO(2) base layer was attributed to the resulting increase in chemical affinity of the ZrO(2) to the HA layer and to the Ti substrate. The osteoblast-like cells cultured on the HA/ZrO(2) coating surface, proliferated in a similar manner to those on the HA single coating and on the pure Ti surfaces. At the same time, the corrosion resistance of Ti was improved by the presence of the ZrO(2) coating, as shown by a potentiodynamic polarization test.     

Influence of hierarchical hybrid micro/nano-structured surface on biological performance of titanium coating

In this article, hierarchical hybrid micro/nano-structured titanium surface was obtained by alkali treating the vacuum plasma sprayed titanium coating following hot water immersing for 24 h. The influences of the surface microstructure on the in vitro and in vivo biologic performance of titanium coating were studied. Human bone marrow-derived stromal cells (hBMSCs) were used for in vitro cytocompatibility evaluation. Compared with the rough titanium coating surface, cell behaviors, such as spread and proliferation were apparently enhanced by mimicking the hierarchical hybrid structure of bone tissue, while ALP expression was lower at days 4 and 7. With the expanding of induction time, the ALP activity rapidly increased on the hierarchical surface. After 10 days induction, it became much higher than that on the rough titanium surface. A canine model was applied for an in vivo evaluation of the bone bonding ability. Histologic examination demonstrated that new bone was formed more rapidly on the hierarchical surface implants than that on the rough titanium surface. All these results indicate that the hierarchical surface is favorable for the response of hBMSCs and early bone bonding.     

Effect of ZrO2-doping of nanosized Fe2O3/MgO system on its structural,surface and catalytic properties

Fe₂O₃/MgO system was prepared by wet impregnation method followed by treatment with different amounts of Zr-dopant salt then heating at 500 and 700 °C. The dopant concentrations were 0.48, 0.95 and 1.4 mol% ZrO₂. Pure and variously doped solids were characterized using XRD, N₂-adsorption isotherms carried out at ?196 °C and catalytic decomposition of H₂O₂ in aqueous solution at 25–35 °C. The results revealed that the nanosized MgO phase was only detected in the diffractograms of pure and doped solids calcined at 500 °C. Heating pure and doped solids at 700 °C produced nanosized MgFe₂O₄ phase together with MgO phase. Pure and ZrO₂-doped solids calcined at 500 and 700 °C are mesoporous adsorbents. The doping process brought about a measurable decrease in the S_BET of Fe₂O₃/MgO system with subsequent increase in its catalytic activity. The catalytic activity of the investigated system toward H₂O₂ decomposition, expressed as reaction rate constant per unit surface area was found to increase as a function of dopant concentration. The maximum increase in the reaction rate constant per unit surface area measured for the reaction carried out at 30 °C attained 125% for the heavily doped samples. This significant increase was based on the catalytic activity of pure catalyst sample measured under the same conditions.     

碳素生物涂层材料的微结构与抗凝血性能研究

通过磁过滤等离子沉积技术,在不同衬底负偏电压下(0～-80V)制备四配位氢化非晶碳薄膜(ta-CH),通过紫外-可见吸收光谱(UV)测定薄膜的微结构和光学带隙.通过血小板粘附实验研究了不同微结构ta-CH薄膜的抗凝血性能,在扫描电镜(SEM)下观察血小板形态、聚积变形等情况,统计血小板粘附数量.并以美国PolyMedica公司生产的、临床应用最好的抗凝血生物材料"聚碳酸酯聚胺酯(Phrono flex)"作阴性对照,以最差的玻璃作阳性对照进行对比实验.实验结果表明在不同的负衬底偏压条件下制备的a-CH薄膜,其sp3含量不同,抗凝血性能也不同.在衬底负偏电压为-20V下制备的ta-CH薄膜,具有优良的抗凝血液性能.     

微陨石撞击下ZrO2涂层的损伤效应

利用静电式粉尘加速器模拟空间微米级陨石粒子,研究了不同撞击速度下航天器外表面ZrO2涂层的损伤形式.结果表明,ZrO2热控涂层在空间微陨石的撞击下,涂层表面形成砂蚀损伤,导致光学性能发生变化热控涂层表面破坏程度及形式与碰撞速度有关,ZrO2涂层表面砂蚀损伤是导致涂层光学性能变化的原因.ZrO2涂层吸收发射比由碰撞前的0.23变为碰撞后的0.75,涂层性质由太阳吸收体向绝对反射体转变.     

晶粒细化对Al2O3／ZrB2／ZrO2复合陶瓷材料力学性能的影响

采用普通球磨细化工艺和两次球磨细化工艺制备出两类Al2O3/ZrB2/ZrO2复合陶瓷材料,并对材料的硬度、断裂韧性和抗弯强度进行了测试和分析.结果表明,两次球磨细化工艺可以明显降低ZrB2/ZrO2晶粒的尺寸至0.2～0.4μm,使其在Al2O3基体内的分布更均匀,并能有抑制Al2O3晶粒的异常长大.与普通细化工艺相比较,此工艺改变了材料的断裂模式,强化了晶界的结合能力,使复合材料的综合力学性能得到了更大程度的改善,其中抗弯强度和硬度最多提高了48%和41%.     

表面TiO2包膜对制备CaCO3／TiO2复合材料颜料性能的影响

采用机械力化学方法，通过对碳酸钙进行表面TiO2包膜制备了CaCO3／TiO2复合材料，对CaCO3／TiO2复合材料的颜料性能、CaCO3和TiO2的结合形态与反应机理进行了研究。结果表明：CaCO3／TiO2复合材料形成了具有类似钛白粉的颜料性质，遮盖力为钛白粉的90％，吸油量和紫外线吸收功能与钛白粉相同；CaCO3／TiO2复合材料中TiO2在CaCO3颗粒表面形成均匀包覆和二者通过各自表面羟基形成化学结合是导致其呈现钛白粉颜料性质的内在机制。     

Constructing bio-layer of heparin and type IV collagen on titanium surface for improving its endothelialization and blood compatibility

The modification of cardiovascular stent surface for a better micro-environment has gradually changed to multi-molecule, multi-functional designation. In this study, heparin (Hep) and type IV collagen (IVCol) were used as the functional molecule to construct a bifunctional micro-environment of anticoagulation and promoting endothelialization on titanium (Ti). The surface characterization results (AFM, Alcian Blue 8GX Staining and fluorescence staining of IVCol) indicated that the bio-layer of Hep and IVCol were successfully fabricated on the Ti surface through electrostatic self-assembly. The APTT and platelet adhesion test demonstrated that the bionic layer possessed better blood compatibility compared with Ti surface. The adhesion, proliferation, migration and apoptosis tests of endothelial cells proved that the Hep/IVCol layer was able to enhance the endothelialization of the Ti surface. The in vivo animal implantation results manifested that the bionic surface could encourage new endothelialization. This work provides an important reference for the construction of multifunction micro-environment on the cardiovascular scaffold surface.     

ZrB2对浸入式水口用ZrO2-C材料性能的影响

浸入式水口渣线材料性能的优劣决定着连铸安全和效率的高低,为提高浸入式水口渣线的性能,本研究在ZrO2-C材料中加入ZrB2,探讨ZrB2对ZrO2-C材料性能尤其是抗侵蚀性的影响.结果表明:ZrB2添加到ZrO2-C材料中后,会显著提高材料的抗氧化性,其机理是高温下ZrB2生成B2O3,B2O3在高温下为液相,堵塞气孔,大幅度减缓氧化.适量ZrB2添加到ZrO2-C材料中后,可以提高材料的抗侵蚀性.但ZrB2容易在CO气氛下生成B2O3,B2O3易使氧化锆脱溶、分解,加速ZrO2-C材料的侵蚀.     

TiB2/ZrO2复合材料介电及力学性能研究

以热压烧结制备了TiB2/ZrO2复合材料,研究了其在8.2～12.4GHz的介电特性和力学性能,探讨了材料极化和损耗机理.结果表明,Ib2降低了复合材料的烧结性能;纯ZrO2无明显损耗,Ro2内部价电子随电场移动使基体发生极化,Ib2在材料中形成的导电网络使复合材料复介电常数实部和损耗增加.复合材料的硬度随TiB2体积分数增加而下降,抗弯强度和断裂韧性随TiB2体积分数增加先上升后下降,这是由复合材料相对密度、基体晶粒尺寸以及TiB2的韧化作用等因素共同决定的.     

钛材料表面固定多聚赖氨酸-肝素纳米颗粒以改善血液相容性的研究

通过将多聚赖氨酸(PLL)-肝素纳米颗粒固定在多巴胺涂覆的钛表面,以改善其血液相容性。利用zeta电位仪及甲苯胺蓝法检测纳米颗粒的粒径及成分,通过傅立叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)及水接触角等对颗粒固定前后表面理化性质的变化进行表征。通过体外血小板粘附实验、肝素释放及活化部分凝血活酶时间(APTT)检测对改性样品的血液相容性进行评价。结果表明,PLL-肝素纳米颗粒成功固定在多巴胺沉积的钛表面,纳米颗粒的固定有效降低钛材料表面血小板的粘附行为,大大提高了血液相容性。     

Effects of some rare earth oxides and/or SiO2 additions to a commercial ZrO2 paint for coating SiGe thermoelectric materials

The effects of some rare earth oxides (Y₂O₃, CeO₂, Sm₂O₃ or Er₂O₃) and/or SiO₂ additions to a commercial oxide paint (mainly ZrO₂) were studied as coatings for SiGe thermoelectric materials. No spalling occurred in the samples prepared from coatings containing small amounts of Er₂O₃, SiO₂ or both CeO₂ and SiO₂ while heating for 1322 h at 1080° C in vacuum, and the sublimation of silicon and/or germanium was reduced significantly. The improvements imparted by these oxide additions to the commercial oxide paint is thought to be due to decreased internal stress of the surface oxides. The addition of Y₂O₃ and Sm₂O₃ had a detrimental effect.     

Preparation and characterization of ZrO2 porous nanosolid and its composite fluorescent materials

ZrO₂ porous nanosolid has been successfully prepared by a novel hydrothermal hot-press (HHP) method, using ZrO₂ nanoparticles as the starting material. Furthermore, a kind of O, O-donating chelating regent, morin was assembled into the pores of ZrO₂ porous nanosolids, and a morin/ZrO₂ porous nanocomposite was obtained. Because of the interaction between morin molecules and the surface of ZrO₂ porous nanosolid, a blue-shift of the photoluminescence (PL) peak was observed in ZrO₂/morin nanocomposite by comparing with that of morin.     

Nano-magnetic particles used in biomedicine: Core and coating materials

Magnetic nanoparticles for medical applications have been developed by many researchers. Separation, immunoassay, drug delivery, magnetic resonance imaging and hyperthermia are enhanced by the use of suitable magnetic nanoparticles and coating materials in the form of ferrofluids. Due to their low biocompatibility and low dispersion in water solutions, nanoparticles that are used for biomedical applications require surface treatment. Various kinds of coating materials including organic materials (polymers), inorganic metals (gold, platinum) or metal oxides (aluminum oxide, cobalt oxide) have been attracted during the last few years. Based on the recent advances and the importance of nanomedicine in human life, this paper attempts to give a brief summary on the different ferrite nano-magnetic particles and coatings used in nanomedicine.     

碳/碳复合材料SiC/MoSi_2/ZrO_2涂层体系氧化烧蚀性能

抗氧化涂层技术是解决碳/碳复合材料高温抗氧化性的最有效技术途径之一。为了提高材料在1 800℃以上的高温抗氧化性能,首次采用包埋法、涂刷法和等离子喷涂法在碳/碳复合材料表面制备出SiC/MoSi_2/ZrO_2梯度抗氧化涂层体系。采用SEM/EDS、结合力和粗糙度测试对涂层表面及断面形貌进行微观分析,利用等离子风洞对整个涂层体系进行氧化试验。结果表明:基体、过渡层和高温抗氧化层之间结合力良好,高温抗氧化层厚度均匀、结构致密。经等离子风洞氧化600s后,涂层表面温度达到1 850℃,氧化质量失重速率仅为3.15×10~(-6) g/(cm~2·s)。表明SiC/MOSi_2/ZrO_2梯度抗氧化涂层体系在1 800℃以上的高温环境下具有很好的抗氧化性能。     

Formation and bioactivity of porous and nanostructured TiO2/beta-TCP coating on titanium

Titanium and its alloys have been widely used as hard tissue implants due to their excellent mechanical properties and biocompatibility. However, their near bio-inertness and metallic ion release are still the problems with clinical uses. In this paper, porous and nanostructured TiO2/beta-tricalcium phosphate (beta-TCP) composite coatings were prepared on titanium substrates by plasma electrolytic oxidation (PEO) in a Ca and P-containing electrolyte. The influence of PEO electric current density on phase composition and bioactivity of the coatings were studied. X-ray diffraction, scanning electron microscopy and Fourier transfer infrared spectroscopy were utilized to characterize the phase composition and microstructure of the coatings. Simulated body fluid immersion tests were employed on the coatings to evaluate their bioactivity. The results reveal that TiO2/beta-TCP composite coating with pores size less than 10 microm and grains of 50-100 nm in size was prepared. The electric current density of PEO is an important factor in the formation of the composite coating. The TiO2/beta-TCP composite coating shows good bioactivity, which are attributed to the incorporation of beta-TCP.     

Microstructure and mechanical properties of mullite/ZrO2 composites

The sintering, microstructure and toughness of mullite/ZrO₂ composites with increasing amount of ZrO₂ (0 to 20 vol %) have been studied. A very active premullite powder has been used as matrix. TheK _IC values increase from 2.1 to 3.2 MN m^?3/2 as the volume fraction of zirconia increases from 0 to 0.2. The realtive fraction of tetragonal zirconia decreases as the volume fraction of ZrO₂ increases to reach ～0.1 in the sample with 0.2 volume fraction of ZrO₂. The presence of ZrO₂ enhances the sintering rate and end-point density of the composites. Finally, the increasing toughness in mullite/ZrO₂ composites has been explained by a grain boundary strengthening mechanism produced by a metastable solid solution (～0.5 wt %) of ZrO₂ in mullite.     

纳米材料在涂料中的改性和应用

着重介绍纳米材料在涂料中的改性与应用,论述了纳米材料的选择及分散方法,研究表明,纳米材料改性涂料的各项性能显著提高.     

模板整理对SnO2/C遗态材料显微结构及性能的影响

以不同整理工艺处理的苎麻纤维为生物模板,酚醛树脂为黏接剂,经800℃炭化后获得三种苎麻炭模板,再经Sn(OH)4溶胶浸渗和560℃真空原位炭热还原反应制备得三种SnO2/C遗态材料试样.采用XRD和SEM技术分析了苎麻模板整理工艺对SnO2/C遗态材料物相组成和微观形貌的影响,利用自制磨耗仪对比测试了三种遗态材料试样的磨损率.结果表明:三种SnO2/C遗态材料试样在显微结构以及耐磨性能等方面存在明显差异,通过生物模板整理工艺可有效调控遗态材料的微观结构和性能.