碱处理法制备钛合金表面羟基磷灰石涂层

采用碱处理法制备钛基羟基磷灰石涂层,考察了碱液处理中有关钛合金表面活化参数对其诱导羟基磷灰石沉积速度的影响,采用X射线衍射和扫描电镜对样品的化学组成、结构和性能进行了表征,确定了钛合金表面活化处理的最优参数.结果表明,钛基体经10 mol/L氢氧化钠,饱和硝酸钙预钙化处理,模拟体液中培养后,羟基磷灰石沉积速度快,14 d就可形成致密﹑均匀﹑裂纹少的涂层;碱液处理后饱和硝酸钙溶液预钙化可得到片状的羟基磷灰石生物矿化层;且钛基体在600 ℃的热处理是HAP涂层沉积的重要条件之一.与相关研究相比较,该方法的优点在于可在形状复杂的植入体上形成均匀的涂层,工艺简单,并且涂层与基体结合牢固.     

AZ91镁合金表面电沉积透明质酸-羟基磷灰石复合物

目的:为提高镁合金的耐蚀性与生物相容性。方法:利用溶胶-凝胶的方法制备羟基磷灰石并进行XRD物相分析,采用电沉积的方法在镁合金表面制备了一层透明质酸-羟基磷灰石复合层,利用扫描电子显微镜结合EDS能谱仪对膜层进行形貌表征与元素分析,对膜层进行Tafel极化曲线测量。结果:沉积物的含量随着沉积时间的延长而增大,并且沉积物的组分也随着透明质酸溶液中羟基磷灰石含量的变化而变化,羟基磷灰石均匀地分散到了透明质酸膜层中,Tafel极化曲线表明复合物涂层提高镁合金基体的耐蚀性。结论:常温下,采用电沉积的方法能使透明质酸与羟基磷灰石沉积到镁合金表面,并且能提高镁合金基体的耐蚀性。     

模拟体液中电沉积制备磷酸钙盐涂层的研究

采用电沉积方法在模拟体液中制备磷酸钙盐涂层,研究了电流密度、电解液浓度、电沉积时间以及后处理对涂层表面形貌、组分和结构的影响。研究表明：在1～10mA／cm^2电流密度下沉积60～75min可以在模拟体液中制备结晶度较低的磷酸钙盐类涂层,涂层分别经模拟体液、碱液和水热处理后前驱体都转变为羟基磷灰石。     

钛金属表面生物陶瓷涂层研究的现状

骨替换材料与周围骨组织之间的生物活性结合是近10年来研究较多的一种结合方式，其关键是生物材料表面必须具备高的生物活性。利用物理沉积、溶胶—凝胶、电化学沉积以及生物仿生等技术在钛金属表面涂覆具备生物活性的生物陶瓷涂层，是提高钛金属生物活性的有效手段之一。另一类有效方法是用氢氧化钠或双氧水溶液对钛金属进行化学处理，在表面获得一层具备生物活性的二氧化钛．这层二氧化钛除必须富含Ti-OH功能性基团外，还应该是晶态的，这样才能有效地诱发羟基磷灰石晶核的生长，从而使钛金属表面具备高的生物活性。文中对这些表面生物活化处理技术及其生物活化机制作了简单评述。     

乙二胺四乙酸二钠对镍钛合金表面电沉积羟基磷灰石涂层的影响

先用10mol/L的NaOH溶液处理镍钛片,随后采用电沉积法制备羟基磷灰石涂层。电沉积工艺参数为:硝酸钙0.042mol/L,磷酸二氢铵0.025mol/L,EDTA-2Na1.5×10-4mol/L,温度65℃,pH4.5,电流密度1mA/cm2,时间1h。采用扫描电镜、红外光谱仪和能谱仪对所得涂层进行表征。NaOH溶液处理有利于羟基磷灰石的生长。溶液中EDTA-2Na的存在不影响羟基磷灰石的生成,只是促使羟基磷灰石末端聚拢,使羟基磷灰石之间的空隙扩大,并减少涂层的CO3-2含量,增加OH-,有效减少了涂层的镍含量。     

电化学沉积-水热合成法制备羟基磷灰石生物涂层的工艺研究

采用电化学沉积法,在低温条件下从含钙、磷离子的电解水溶液中沉积磷酸钙涂层,经过水热合成获得羟基磷灰石（ＨＡ）涂层．用扫描电镜（ＳＥＭ）、Ｘ射线衍射（ＸＲＤ）和红外光谱（ＩＲ）对涂层的组织结构和化学组成进行分析．结果表明：电化学沉积涂层由ＣａＨＰＯ４·２Ｈ２Ｏ,经水热合成后转变为羟基磷灰石．随蒸气温度和压力的升高,羟基磷灰石的含量增加,在适当条件下可获得纯羟基磷灰石涂层．该方法重复性好,是制备羟基磷灰石生物涂层的理想方法之一．     

碳/碳复合材料表面软复合磷酸钙层

为改进碳／碳复合材料的生物活性，发展了表面软复合磷酸钙层的制备工艺。首先在碳／碳复合材料表面通过离子束辅助沉积技术形成的钛镀层，然后经浓碱液处理后呈多孔网状，该网状结构可在模拟体液（SBF）中诱导沉积出生理磷灰石层，从而在碳／碳复合材料表面形成软复合磷酸钙层。所获得的软复合磷酸钙层厚度约为8μm ，结晶结构为羟基磷灰石，但其Ca,P摩尔比n(Ca)/n(P)低于1．67。     

羟基磷灰石涂层的生物仿生法研究进展

羟基磷灰石的生物复合涂层具有很高的外科应用价值.制备羟基磷灰石复合材料的方法有很多种,其中仿生法模仿了自然界生理磷灰石的矿化机制,在类似于人体组织内环境条件的水溶液中自然沉积出磷灰石层.仿生法具有许多其它方法无可比拟的优越性.本文对近年来文献报道中出现的生物仿生法进行了综述,阐述了各种仿生法中包括对基体进行预处理使其表面官能团化,再将基体在模拟体液中浸泡从而使磷灰石自然沉积的模拟生物矿化的4个阶段的工艺过程及其仿生机理.     

羟基磷灰石抗菌剂的研究

采用离子溶液反应法,制得羟基磷灰石抗菌剂.利用原子吸收光谱研究了不同制备条件对羟基磷灰石载持银离子性能的影响.通过X射线和红外光谱2种分析测试手段,从不同角度对羟基磷灰石抗菌剂结构进行了研究.经自然落菌实验,对未煅烧的羟基磷灰石抗菌剂的抗菌力与经过煅烧处理的羟基磷灰石抗菌剂的抗菌力进行了比较.     

仿生法在AZ91D镁合金表面制备羟基生物涂层

镁基表面制备羟基磷灰石可以使材料同时具备镁良好的力学性能以及羟基磷灰石的耐腐蚀性、生物相容性等特点。本课题通过酸洗、碱洗、活化的处理活化镁合金表面,试样经碱热处理后置于SBF溶液中仿生生成羟基磷灰石。结果表明:随浸泡的Na OH溶液浓度升高,试样表面沉积物质量增加,经15%Na OH浸泡后,试样在SBF中沉积得到的羟基磷灰石量最多。沉积3天后,镁合金表面得到均匀性较好的生物涂层。     

The effects of surface modification of titanium on the absorption rate of hydrogen during cathodic polarization

The surface of titanium was modified by depositing coatings of metals of Group VIII, I_b and IV_b and heat treatment at 700°C in a vacuum. The polarization behavior of the modified specimens were different from that of unmodified titanium, depending upon the nature and quantity of the deposited metals, thus indicating the altered nature of the surface layer. The initial hydrogen absorption rate by the modified specimens during cathodic polarization in 0.5 M H₂SO₄ was measured and the results are discussed in relation to the hydrogen evolution reaction characteristic of the deposited metals, the surface layer composition, etc. Metals which inhibited the formation of the surface oxide layer of titanium increased the hydrogen absorption rate. The surface coverage of atomic hydrogen is suggested to the critical factor in determining the hydrogen absorption rate of titanium. Among the metals studied, Ni was the most significant in improving the hydrogen absorption rate of titanium, resulting in a current efficiency of 62% for hydrogen absorption (2.8 times that of titanium). Pt and Pb had an inhibiting effect on hydrogen absorption, with half the efficiency of untreated titanium. The present results suggest the possibility of controlling the hydrogen absorption rate of titanium during cathodic polarization by surface modification techniques.     

Cerium-doped hydroxyapatite/collagen coatings on titanium for bone implants

The novelty of the present research consists in the possibility of obtaining cerium-doped hydroxyapatite/collagen coatings on the titanium support, to improve the performance of the bone implants. These coatings were deposited on the titanium surface by biomimetic method using a modified supersaturated calcification solution (SCS) additionally containing a cerium source and collagen. Prior to the deposition of the apatite layer, an alkali ÷ thermal oxidation pretreatment has been applied to ensure an increase in the bioactivity of the titanium surface. The coatings were examined by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The EDX and XRD investigations of the coatings indicated that cerium was incorporated in the hydroxyapatite lattice. The collagen presence in the coatings was confirmed by FTIR analysis. The cerium-doped hydroxyapatite/collagen coatings showed good antibacterial efficacy against Escherichia coli and Staphylococcus aureus bacteria, being more effective against Escherichia coli. These coatings have a significant potential to be used in the dental and orthopedic implants, as the osseointegration depends on much more factors than simple formation of hydroxyapatite.     

Design of Experiments (DOE) for the Optimization of Titania–hydroxyapatite Functionally Graded Coatings

Titania–hydroxyapatite functionally graded coatings were deposited on titanium alloy substrates by plasma spraying. Because it was necessary to spray together the titania and the hydroxyapatite powders to obtain the graded system, the first target of the present study was to optimize the process parameters in order to obtain a high-quality coating. A 2³ Design of Experiments was applied to define the optimal values of plasma torch power, hydrogen flux, and spraying distance. This defined set of parameters (38 kW, 5 SLPM, and 90 mm, respectively) was used to spray the most promising graded coating, which was characterized and postheat treated.     

Bioactive Calcium Phosphate Coating on Sodium Hydroxide-Pretreated Titanium Substrate by Electrodeposition

This study examined the characteristics of calcium phosphate coatings deposited on a NaOH-pretreated titanium substrate by electrodeposition in a modified simulated body fluid (SBF) immediately after electrodeposition as well as after the coatings had been immersed in the SBF for 5 d in order to determine the effects of a NaOH pretreatment on the bioactive coating prior to electrodeposition. The results showed that a dense and uniform coating that consisted of brushite and hydroxyapatite had formed on the NaOH-pretreated titanium substrate by electrodeposition. This coating had transformed to a bonelike apatite during immersion in the SBF. This was attributed to the increased surface area of the modified titanium formed after the NaOH treatment as well as the Na⁺ ions released from that surface. Therefore, a NaOH pretreatment is recommended as an effective method for preparing a bioactive calcium phosphate coating by electrodeposition.     

Biomimetic Hydroxyapatite Coating on Metal Implants

The combination of the high mechanical strength of metals with the osteoconductive properties of calcium phosphates make hydroxyapatite coatings on titanium implants widely used in orthopedic surgery. However, the most popular coating method, plasma spraying, exhibits some important drawbacks: the inability to cover porous implants and to incorporate biologically active agents, delamination, and particle release. The aim of this study was to elaborate a dense, strong, and thick calcium-phosphate coating on titanium and porous-tantalum implants using a two-step biomimetic procedure. In the first step, the implants were soaked in a solution that was 5 times more concentrated than regular simulated body fluid (SBF-A solution). A thin but uniform amorphous calcium-phosphate coating was deposited on the metal. Then, the implants were immersed in the SBF-B solution, which had a similar composition as the SBF-A solution, but with decreased contents of crystal growth inhibitors (i.e., Mg²⁺ and HCO₃⁻). This resulted in the fast precipitation of a 30 μm thick crystalline calcium-phosphate coating. The pH of the SBF-B solution and the thickness of the crystalline coating layer were studied as a function of time. The Fourier transform infrared spectra and X-ray diffraction patterns showed that this new coating closely resembles bone mineral. Our biomimetic coating should facilitate rapid bone formation around the implant, reducing therewith the patient's recovery time after surgery.     

仿生法制备钛合金/羟基磷灰石复合涂层的研究

本研究了仿生溶液中钛合金表面沉积羟基磷灰石的技术路线。钛合金经抛磨、清洗．进行酸碱活化处理后，置于模拟体液(SBF)中，最终在钛合金基体上生成羟基磷灰石涂层。     

Pulsed laser deposition of hydroxyapatite-diamondlike carbon multilayer films and their adhesion aspects

We have developed a layered hydroxyapatite/diamondlike carbon/functionally gradient diamondlike carbon-silver/titanium carbide/titanium carbonitride/titanium nitride composite film using pulsed laser deposition. A diamondlike carbon interlayer between a hydroxyapatite coating and the Ti-6Al-4V alloy can serve several purposes, including preventing corrosion of Ti-6Al-4V alloy, overcoming poor adhesion between the hydroxyapatite coating and the titanium oxide surface, and reducing inflammation at the implant/tissue interface. Titanium nitride, titanium carbonitride (TiC _x N _y ), titanium carbide and functionally gradient diamondlike carbon-silver layers were used to improve the adhesion of diamondlike carbon films to Ti-6Al-4V alloy. We envision several potential medical applications for these multilayer materials, including use in orthopedic and dental devices.     

溶胶凝胶法制备钛基羟基磷灰石涂层的研究

混合硝酸钙乙醇溶液和磷酸三甲酯水溶液作为羟基磷灰石(HA)前驱体,利用旋转涂膜技术在钛片表面制备羟基磷灰石涂层.研究了溶胶陈化时间和凝胶热处理温度对涂膜的影响,同时对涂层的生物活性进行了研究.样品利用X射线衍射仪(XRD)和扫描电子显微镜(ESEM)进行表征.结果表明:利用经过24 h陈化的溶胶涂膜的样品在500℃热处...     

基于表面生物学改性的多孔状二氧化钛/磷灰石复合薄膜的制备

在钛合金表面采用微孤氧化得到一层多孔状的具有生物活性的二氧化钛，经随后水热处理可形成羟基磷灰石薄膜，提高钛合金表面的生物学性能，用SEM、XRD、EDX分析了薄膜的组织、结构和化学组成，同时考察了微弧氧化得到的二氧化钛膜的生物活性，结果表明，在室温条件下从含钙、磷离子的电解液中在钛合金基体上微弧氧化得到一层二氧化钛薄膜，蒸汽处理后得到具有生物活性的二氧化钛/羟基磷灰石复合薄膜，该膜多孔均匀，且生物活性高，有利于骨组织的吸附和生长。