预钙化对医用钛合金表面沉积钙磷层的影响

通过SEM，XRD和测量离子浓度的方法，研究了预钙化对医用钛合金表面沉积钙磷层的诱导作用。结果表明，在用化学方法对钛合金进行表面改性的过程中，预钙化明显增强羟基磷灰石在钛合金改性表面上的沉积能力。     

炭/炭复合材料声电沉积钙磷生物活性涂层的生长机理

通过声电沉积在炭/炭复合材料表面制备钙磷生物活性涂层,采用SEM（带EDAX）,XDR,FTIR研究电沉积时间对钙磷生物活性涂层的形貌、结构和组成的影响.实验结果表明：沉积初始先在炭/炭表面形成无定形层,片状磷酸氢钙（DCPD）在其表面生长,随着电沉积时间的延长,逐渐向针状的羟基磷灰石Ca10（PO4）6（OH）2（HA）转变,涂层厚度和n（Ca）/n（P）不断增加,涂层的结晶度和电解液的pH值下降.涂层为缺钙磷灰石.同时探讨了在炭/炭复合材料表面钙磷生物活性涂层的生长机理.     

水热处理液配方对羟基磷灰石生长的影响

将Ti6-A14-V放入含有钙磷元素的溶液中进行微弧氧化处理,在其表面可以生成一层含有钙磷元素的氧化膜.针对钙磷元素含量以及分布在微弧氧化过程中不容易控制的问题,对水热处理液进行改进,在改进的水热处理液中进行水热处理.结果表明:氧化膜表面上羟基磷灰石在数量、尺寸以及均匀性上都有很大提升.     

碳／碳复合材料表面声电沉积磷灰石动力学研究

采用声电沉积技术，在碳／碳复合材料表面制备了生物活性磷酸钙涂层。扫描电镜、X射线衍射、红外反射以及X射线能谱分析表明所制涂层呈现网状结构，其由钙磷比为1．64、含碳酸根的羟基磷灰石组成。根据扫描电镜观察，描述了磷灰石的形成过程。羟基磷灰石的沉积过程可简化为两步——钙磷离子向碳／碳阴极表面运动和羟基磷灰石在碳／碳表面生长。基于此描述，导出了羟基磷灰石沉积动力学公式，并且发现，沉积过程受扩散控制，扩散活化能是30．3kJ／mol．     

预钙化处理提高钽的表面生物活性

为提高钽的生物活性,对钽进行了NaOH溶液碱处理,利用模拟体液(SBF)浸泡实验探索碱处理的最佳浓度。碱处理后的钽又分别在CaCl2溶液和K2HPO4溶液中进行预钙化处理。钽经过0.7mol/L的碱处理后,在SBF中浸泡2周,表面即可被羟基磷灰石覆盖。经预钙化处理后,钽在SBF中浸泡4天,表面即可覆盖一层羟基磷灰石,说明预钙化大幅提高了钽的生物活性。其机理是预钙化处理可使样品表面迅速完成钙磷化合物的形核,浸入SBF以后羟基磷灰石可以迅速长大。     

阳极电压对医用钛材微弧氧化的影响

采用恒压模式微弧氧化对医用钛材表面改性，制备出含钙磷的TiO2复合膜层，借助于SEM、XRD和EDS研究了阳极电压对膜层的形貌、相组成和钙磷含量的影响，探讨了膜层表面和孔内钙磷的分布规律。研究结果表明，低压处理获得小孔径和锐钛矿型TiO2为主的膜层，钙磷含量和钙磷比较低，并且微孔内的钙磷含量少于膜层表面。随着阳极电压的提高，膜层的孔径增大，金红石型TiO2增多，钙磷含量和钙磷比增大。高压处理时微孔内的钙磷含量与膜层表面相当。提高微弧氧化恒压电压，可以促进Ti氧化反应。经过微弧氧化后的Ti表面多孔形貌、晶型和钙磷含量将对后续的水热处理羟基磷灰石的生成有重要影响。     

钙磷含量对TA2医用钛合金微弧氧化膜层的影响

在不同钙磷原子比的硅酸盐电解液中,通过微弧氧化技术在钛合金的表面制备陶瓷膜层,研究了溶液中钙磷原子比对膜层结构和成分的影响,并讨论了膜层形成机理。结果表明,膜层中的元素含量与电解液中的元素含量为非线性关系;钙磷原子比为8时,膜层中的钙磷原子比接近羟基磷灰石。此外,电解液浓度增加增大膜层表面粗糙度。     

激光修饰在制备生物活性表面中的应用

回顾了金属基体表面羟基磷灰石（HA）或合金层的激光重熔（LSRM）、金属表面激光熔凝（LSM）以及脉冲激光沉积钙磷层（PLD）等激光表面处理技术,利用LSRM、LSM、PLD可以明显改善基体表面的耐蚀性和生物相容性。     

碱液处理钛合金表面软复合磷酸钙层

钛合金（Ti6Al4V)经过NaOH碱液处理后表面形成了多孔网状、弱结晶的钛酸钠凝胶层；随碱液浓度和处理时间增加，孔的尺寸增加。钛酸钠凝胶层可在快速钙化溶液中诱导沉积出（002）取向的磷酸八钙和／或磷灰石；而在模拟体液中诱导沉积出无取向的骨状磷灰石。碱液处理条件和钙磷溶液的离子种类、浓度和pH值是影响钛合金软复合磷酸钙层成分和沉积速度的两个因素。     

电解液成分对纯钛表面微弧氧化膜结构与生物活性的影响

采用微弧氧化处理技术,在纯钛TA2表面制备了含钙磷的多孔复合氧化膜,用SEM、XRD、EPMA等分析了电解液成分对氧化膜形貌、成分、相构成及生物活性的影响。结果表明:纯钛表面微弧氧化后原位生成的含钙磷多孔性复合氧化膜由锐钛矿相TiO2,金红石相TiO2和基体Ti组成;随电解液中钙磷摩尔比(Ca/P)值的增大,表面孔洞数量增多、直径变小,膜中Ca/P值增大,锐钛矿相TiO2减少、金红石相TiO2增多;当电解液中Ca/P=5时得到的氧化膜的Ca/P值为1.528,将该样品经碱液处理后再在快速钙化溶液(FCS)中浸泡2 d后即有羟基磷灰石HA形成,表明其具有良好的生物活性。     

Calcium phosphate nucleation on cellulose fabrics

Nonwoven cellulose (regenerated, oxidized) fabrics were coated with hydroxy carbonated apatite (HCA) using a procedure based on a biomimetic method. Simulated body fluid (SBF) with a high degree of supersaturation (5xSBF) was applied to accelerate the biomimetic formation of bonelike apatite on the cellulose fabrics. After creating calcium phosphate nuclei on the cellulose fibers in a first 5xSBF with high Mg²⁺ and HCO₃⁻ concentrations, the cellulose fabrics were additionally soaked in a second 5xSBF which was optimized with respect to accelerated crystal growth by reduced Mg²⁺ and HCO₃⁻ concentrations. The hydroxy carbonated apatite (HCA) layer thickness increased from 6 μm after 4 h of soaking in the latter solution to 20 μm after 48 h. The amount of CO₃²⁻ substituting PO₄³⁻ in the hydroxyapatite (HA) lattice of the precipitates can be varied by changing the soaking time.     

Effect of a bioactive glass-ceramic on the apatite nucleation on titanium surface modified by micro-arc oxidation

The aim of this work was to evaluate the ability of a bioactive glass-ceramic to induce the apatite nucleation on the titanium oxide layer produced by micro-arc oxidation. “In vitro” tests were carried out on a simulated body fluid solution in two different manners: one group was soaked in the SBF, while the other group was soaked together with the bioactive glass-ceramic. Results revealed that after 7 days, the specimens soaked in SBF were covered with an amorphous calcium phosphate layer, while the specimens soaked in SBF plus glass-ceramic formed a crystalline apatite layer, suggesting thus, that the glass-ceramic provides silanol groups that accelerated the hydroxyapatite apatite precipitation on the anodic TiO₂ layer.     

在Q235钢表面原位生长的氧化铁膜对其在含Cl-溶液中腐蚀行为的影响Ⅰ-原位生长的γ-FeOOH膜的防护性能

    利用动电位极化曲线和交流阻抗谱等电化学测量技术,研究了Q235钢表面原位生长的γ- FeOOH膜在0.25 mol/L Na₂SO₄+10^-4mol/L NaCl、0.25 mol/L Na₂SO₄+10-3mol/L NaCl、0.25 mol/L Na₂SO₄+10^-2 mol/L NaCl水溶液中的电化学行为及在不同浓度的Cl^-水溶液中γ-FeOOH膜对Q235钢的保护作用.结果表明,Cl^-含量较低时,γ-FeOOH膜的存在明显地促进了Q235钢的阴极反应,该膜对基材无保护作用;随Cl-浓度的增加,阴极电流密度大幅减小,当Cl^-浓度达到10^-2 mol/L时,γ-FeOOH 膜能在一定程度上抑制基材的腐蚀,此时γ-FeOOH膜表现出对基材有保护作用.     

MoO42-与 Zn2+对镁合金在 NaCl 溶液中的协同缓蚀作用

采用动电位极化曲线法,结合腐蚀后的表面微观形貌及EDS能谱分析,研究了MoO42-与Zn2+对AZ31镁合金在3.5%NaCl溶液中的协同缓蚀性能。结果表明:0.005 mol/L Zn2+与0.05 mol/L钼酸钠联合作用,可有效抑制镁合金在NaCl溶液中的腐蚀,Zn2+促进MoO42-在合金表面的吸附,缓蚀效果优于单一的钼酸盐缓蚀剂。缓蚀机制是:钼酸盐与Zn2+协同作用,使镁合金表面形成更为致密的钝化膜,从而抑制镁合金的腐蚀。     

Preparation of a self-assembled monolayer on iron by the formation of a covalent bond between carbon and iron atoms

A self-assembled monolayer (SAM) of toluene moiety CH₃C₆H₄- was prepared on an iron electrode by electrochemical modification in a deaerated acetonitrile (AN) solution of p-toluenediazonium tetrafluoroborate CH₃C₆H₄N₂BF₄ (TDFB). The protection of the modified electrode was examined by polarization measurements in an oxygenated 0.5 M NaCl solution after immersion in the solution for 1.5 and 4.0 h. The average values of protective efficiency, P for the films prepared by modification in the TDFB solution at −1.013 V/Ag/Ag⁺AN for the modification time, t_m more than 5 min were fairly high, 78.1% and 53.6% at 1.5 and 4.0 h of the immersion time, t, respectively. However, X-ray photoelectron spectra of the iron surface modified with TDFB for 10 min revealed that the film thus prepared on iron was a polymer of the toluene moieties. A layer formed by the cathodic modification in the TDFB solution for 1 min seemed to be a monolayer of the toluene moiety, revealed by X-ray photoelectron spectra of the surface coated with the layer. The contact angle on the coated surface using a drop of water supported the formation of toluene SAM. The P values of the layer for iron corrosion in 0.5 M NaCl were 31.8% and 28.9% at 1.5 and 4.0 h of t, respectively, being a little higher than those of the toluenethiol CH₃C₆H₄SH SAM. The higher values may be attributed to the formation of a strong covalent bond between carbon and iron atoms.     

Investigation of corrosion behaviors at different solutions of boronized AISI 316L stainless steel

In this study, corrosion behaviors of boronized and non-boronized AISI 316L stainless steel (AISI 316L SS) were investigated with Tafel extrapolation and linear polarization methods in different solutions (1 mol dm^?3 HCl, 1 mol dm^?3 NaOH and 0.9% NaCl) and in different immersion times. AISI 316L SS were boronized by using pack boronizing method for 2 and 6 hours at 800 and 900°C within commercial Ekabor®-2 powder. Surface morphologies and phase analyses of boride layers on the surface of AISI 316L SS were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis. SEM-EDS analyses show that boride layer on AISI 316L SS surface had a flat and smooth morphology. It was detected by XRD analyses that boride layer contained FeB, Fe₂B, CrB, Cr₂B, NiB and Ni₂B phases. Boride layer thickness increases with increased boronizing temperature and time. The corrosion experiments show that boride layer significantly increased the corrosion resistance of the AISI 316L SS in 1 mol dm^?3 HCl solution. While no positive effect of the boride layer was observed in the other solutions the corrosion resistance of the borid layer on AISI 316L SS was increased in all solution with the increase of the waiting periods.     

Functionalization of the surface of ceramic membranes with 3-mercaptopropyl groups using the sol-gel method

Tubular ceramic membranes based on α-Al₂O₃ were functionalized with 3-mercaptopropyl groups using the sol-gel method. The formation of the polysiloxane layer on the inner surface of the membranes was confirmed by SEM images and FTIR spectroscopy data. The functionalized membranes (identically to the original one) retain the high performance typical of highly efficient microfiltration membranes (320–690 L/m² h); however, they can be used to remove silver(I) ions from water due to the formation of complexes between thiol groups of the active layer and silver(I) ions. It was also shown that the decreasing concentration of functionalizing sol produces a thinner surface polysiloxane layer with more active sites available for the sorption of Ag⁺ ions. Thus, fourfold dilution of the starting sol results in a tenfold increase in the sorption of Ag⁺ ions calculated per mass unit of the functionalizing layer (from 23 to 203 mg/g).     

Effect of Ti-OH formation on bioactivity of vacuum plasma sprayed titanium coating after chemical treatment

The effect of Ti-OH groups on bioactivity of NaOH treated titanium coating was investigated in this paper. The NaOH-heat treatment was also applied to modify the titanium coating for comparison. The results show that the amount of Ti-OH groups was important to induce apatite formation on the treated titanium coating. When the NaOH treated titanium coating was exposed to SBF, it released Na⁺ ions from the sodium titanate layer on its surface into the SBF via exchanging with H₃O⁺ ions in the fluid and Ti-OH groups were rapidly formed on the surface. So the NaOH treated titanium coating has good bioactivity in simulated body fluid (SBF). The amount of Ti-OH groups on the titanium coating was reduced after heat treatment, so the bioactivity of NaOH-heat treated titanium coating was obviously affected.     

Apatite formation in Hanks' solution on β-Ca2SiO4 films prepared by MOCVD

β-Ca₂SiO₄ film in a single phase was prepared by metalorganic chemical vapor deposition (MOCVD) and immersed in Hanks' solution to evaluate the apatite formation ability. Apatite formed on the surface of the β-Ca₂SiO₄ film after immersion for 1 d. A dense apatite layer covered the β-Ca₂SiO₄ film surface after immersion for 7 d. CO₃²⁻ and PO₄³⁻ groups were identified by Fourier transform-infrared spectroscopy (FT-IR) after immersion for 1 d. The shape of apatite changed from granular to needle-like to densely packed granular with increasing immersion time from 1 d to 14 d.     

CMAS corrosion resistance characteristics of RE50TaxZr50-xO175+0.5x thermal barrier oxides in RE2Zr2O7-RETaO4 systems

The corrosion resistance characteristics of RE-rich RE₅₀Ta_xZr_50-xO_175+0.5x oxides in RE₂Zr₂O₇-RETaO₄ systems to calcium-magnesium-alumino-silicate (CMAS) at 1300 °C, and the influence of RE³⁺ and Ta⁵⁺ on chemical reactions and reactive crystallization of CMAS melts were investigated. The results show that following the thermochemical reactions, apatite, pyrochlore, reprecipitated fluorite and residual Yb(Y)TaO₄ phases were the predominant reaction products. Formation abilities of apatite and pyrochlore were found to be proportional to the ionic radius of RE³⁺. The increase of Ta⁵⁺ amount can decrease the number of available RE³⁺ to form apatite. Moreover, the resistance characteristic to CMAS corrosion in RE₅₀Ta_xZr_50-xO_175+0.5x systems was decided by the combined action of apatite and pyrochlore phases. The cohesive mixture of apatite and pyrochlore phases can generate a dense layer near the reaction front, which had a positive effect on suppressing CMAS infiltration. The ability of the fluorite + RETaO₄ two-phase field was determined to be sufficient to mitigate CMAS corrosion.