等离子喷涂-水热处理制备二氧化钛-羟基磷灰石复合涂层

为克服等离子喷涂羟基磷灰石生物涂层在结合强度和成分上的缺点，通过在钛合金基体上等离子喷涂二水磷酸氢钙和二氧化钻(锐钛矿型)复合粉末，并后续水热处理，制备了二氧化钛—羟基磷灰石复合涂层。结果表明：二水磷酸氢钙和二氧化钛复合粉末的等离子喷涂涂层由CaHPO4,Ca2P2O7,Ca3(PO4)2，非晶磷酸钙和二氧化钛组成。水热处理涂层由羟基磷灰石和二氧化钛组成，升高水热处理温度可提高涂层中羟基磷灰石的结晶性。随着原始粉中二氧化钛加入量的增加，喷涂涂层中磷酸钙的含量和水热处理涂层中羟基磷灰石的含量减少，羟基磷灰石的晶体形貌从细针状变为小颗粒状，喷涂涂层和水热处理涂层的结合强度也随之升高。当二氧化钛的质量分数为60％，水热处理涂层的结合强度可达17MPa。     

羟基磷灰石梯度涂层的制备及其结构特征

通过改变电结晶电流密度在钛合金表面制得内部致密,外部多孔的ＣａＨＰＯ４·２Ｈ２Ｏ涂层,经碱液处理转变为羟基磷灰石。ＳＥＭ,ＸＲＤ分析及粘接拉伸试验表明：电交小时得到的内部涂层致密,与基体有较高的结合强度;随电流密度增加得到的涂层由内向外孔隙率逐渐增大,晶体变为细针状。这种梯度结构实现了生物涂层结合强度和表面形态的协调兼顾。     

以葡萄糖为造孔剂制备多孔羟基磷灰石涂层

采用电泳沉积方法在钛基材表面制得羟基磷灰石(hydroxyapatite,HA)/葡萄糖复合涂层,经烧结处理得到多孔HA涂层。采用红外光谱仪、扫描电镜、X射线衍射和热重分析表征了涂层的组成、表面形貌、物相组成及热稳定性,黏结-拉伸实验测定涂层与基体的结合强度,人体模拟体液(simulated body fluid,SBF)浸泡测定涂层的生物亲合性。结果表明:经700℃烧结处理,复合涂层中的葡萄糖微粒热分解得到多孔HA涂层,孔径为2～20μm,涂层与基体的结合强度可达17.6MPa;在1.5倍SBF(各离子浓度为SBF的1.5倍)中浸泡5d后,多孔HA涂层表面碳磷灰石化,呈现良好的生物亲合性。     

溶胶凝胶法制备羟基磷灰石/TiO2复合生物活性涂层的研究

通过溶胶凝胶法在纯钛基体上制备了羟基磷灰石/TiO2复合生物活性涂层.HA可以提高钛基的生物活性,TiO2可以提高涂层与基体的物理、化学相容性和结合强度.HA和TiO2溶胶由前驱体制得,按不同物质的量比直接混合两种溶胶来制备复合溶胶.使用XRD、SEM研究了不同温度下热处理后涂层的组成和结构.实验结果表明HA的结晶度和晶粒随着温度的升高而提高和变大;涂层表面为连续多孔结构.粘结拉伸结果表明复合涂层与基体结合良好,较纯HA涂层与基体的结合强度有较大提高.复合涂层试样于SBF中浸泡2d、7d和14d的SEM分析结果表明复合涂层表面的磷灰石形成量较高.电位动力学曲线分析表明复合涂层可以提高基体的耐蚀性.     

水热电沉积法制备羟基磷灰石/氧化钛复合涂层的研究

采用水热电沉积法．在钛金属基体￡：成功制备了羟基磷灰石(hydroxyapatite,HA)氧化钛(HA／TiO2)复合涂层．对涂层的表面形貌、相组成、TiO2共沉积量、热稳定性和结合强度进iir研究。实验结果表明：复合涂层具有较均匀的微观结构。TiO2的加入明显改善了涂层与基体的结合强度．涂层中TiO2含量越高．结合强度的提高也越显著。在200℃．100g／L TiO2条件下．电沉积制备的HA／TiO2复合涂层的结合强度为21.0MPa,约为纯HA涂层的2倍。TiO2共沉积量随电解液中TiO2浓度的提高逐渐增加;随电解液温度的提高先增后降,在160C达到最大。涂层经800℃热处理后,TiO2促使HA部分分解为β-磷酸钙(β-tricalciumphosphate,β-TCP)和CaO;经1200℃热处理后,HA和TiO2发生相互作用生成α-TCP和CaTiO3。     

电泳沉积和反应结合制备羟基磷灰石/氧化铝复合涂层

在金属表面用电泳沉积(electrophoretic deposition, EPD)法制备羟基磷灰石(hydroxyapatite, HA)涂层的主要问题是结合强度较低.为了提高HA涂层与基体的结合强度,先采用EPD在钛表面制得羟基磷灰石/铝(hydroxyapatite/aluminum, HA/Al)复合涂层,然后采用反应结合方法(reaction bonding process)制备羟基磷灰石/氧化铝(hydroxyapatite/aluminum oxide, HA/Al2O3)复合涂层,并与相同条件下制备的HA单一涂层进行比较研究.用扫描电镜表征涂层的表面和横截面形貌.用能量散射X射线衍射(X-ray diffraction, XRD)谱分析HA/Al2O3复合涂层的化学组成.用XRD仪研究涂层的物相组成和热稳定性.通过黏结-拉伸实验测定HA涂层与基体的结合强度.结果表明:通过850℃热处理,HA/Al复合涂层中的Al粉发生氧化反应生成Al2O3,经反应结合得到HA/Al2O3复合涂层;反应结合提高了HA涂层的致密化程度且降低了基底钛表面的氧化程度;与单一HA涂层相比,HA/Al2O3复合涂层与基底间的结合强度得到明显提高.     

沉积电压对碳/碳复合材料表面羟基磷灰石涂层相组成及显微结构的影响

采用水热电沉积法在碳/碳复合材料表面制备了羟基磷灰石(hydroxyapatite,HAp)涂层,用X射线衍射、扫描电子显微镜,万能材料试验机等测试手段对涂层进行了表征,研究了沉积电压对HAp涂层晶相和显微结构的影响.结果表明:随着沉积电压的升高,HAp涂层的衍射峰强度有所增加,涂层结晶程度变好,涂层更加致密和均匀;涂层的沉积量和结合强度随着沉积电压的升高而增加.在沉积电压为10V时,涂层的厚度达到了60μm,结合强度为19.8 MPa.     

复合电沉积制备HA/Ag生物陶瓷涂层

在电沉积羟基磷灰石(hydroxyapatite，HA)涂层的电解液中加入Ag粉，通过复合电沉积技术制备HA／Ag复合涂层，比较了不同工艺条件对涂层中Ag含量的影响，以及银对复合涂层结合强度、涂层组成和结构的影响。实验结果表明：复合涂层中Ag的含量随主盐浓度的减小、电流密度的减小和沉积时间的延长而增大。HA／Ag复合涂层经750℃烧结2h后的结合强度明显高于HA涂层，且随Ag含量的增加而提高，可达12．4MPa。当烧结温度高于750℃时，Ag起催化剂作用，促进HA发生了分解。     

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。     

微弧氧化和电泳沉积复合制备羟基磷灰石/TiO2复合涂层及其生物学特性

采用微弧氧化和电泳沉积复合的方法,在钛样品表面沉积了羟基磷灰石(hydroxyapatite,HA)/TiO2复合涂层.用扫描电子显微镜,能量散射X射线能谱分析和X射线衍射对复合涂层的表面形貌、形成过程、元素组成及含量变化、相组成进行了观察和分析.通过剪切粘结实验确定了复合涂层与基体的结合强度,并在高温消毒后,将成骨样细胞MC-3T3-E1接种于试件表面进行培养以评估HA/TiO2复合涂层的生物学性能.结果表明形成的复合涂层由内层致密的TiO2层、中间HA/TiO2混合过渡层和外层HA层构成,其中HA含量呈梯度变化,使TiO2层逐渐向HA层过渡.HA/TiO2复合涂层和基体间的结合强度约为(19.3±2.5)MPa.通过细胞免疫荧光染色观察到细胞在培养3 h就可附着于复合涂层表面并形成良好的铺展,而且随着培养时间的延长,细胞的形态更加舒展,附着在复合涂层表面的细胞数量亦逐渐增加,初步表明复合涂层具有较好的生物学和力学性能.     

碳纤维表面电沉积合金（复合）镀层初步研究

采用电化学沉积的方法,在聚丙烯腈基碳纤维表面制备了Ni–Fe、Fe–P、Ni–B合金及Fe–Cr2O3复合镀层。结果表明:碳纤维表面的预处理对合金(复合)镀层与基底间的结合力有重要影响。扫描电子显微镜结果显示,未经活化处理的碳纤维表面镀层与基体的结合力差,表面有裂纹;表面活化处理后的镀层细致,均匀,结合力好。通过改变与合金元素相应的电解质浓度可改变镀层中合金元素的含量,获得具有不同合金含量的、与碳纤维结合紧密的合金或复合镀层。     

Electrochemical synthesis and characterization of polypyrrole-poly(styrene sulfonate) composite coatings on carbon fibers

Polypyrrole-polystyrene sulfonate composite coatings have been formed on carbon fibers by an aqueous electrochemical process. The effects of process parameters such as applied current density, monomer concentration, electrolyte concentration, and the reaction time, on the electrochemical polymerization of pyrrole onto carbon fibers were investigated. The rate of formation of the coatings increased with the current density and pyrrole concentration. It was, however, independent of electrolyte concentration, especially for polystyrene sulfonate concentration [PsSNa] of 0.05–0.25 M. At higher electrolyte concentration [PsSNa] ≥ 0.30 M, the rate of coatings formation increased with electrolyte concentration. The order of the rate of polymerization with respect to the electrolyte concentration was shown to be 0 and 1.0 at low and high electrolyte concentration, respectively. The polymerization potential, Ep, increased with the current density and decreased with pyrrole concentration. SEM micrographs showed that the morphology of coatings varied with the electrolyte concentration. At low electrolyte concentration, the coatings were rough and granular; however, at higher electrolyte concentration the coatings were smooth and uniform. The doping of polypyrrole films by polystyrene sulfonate ion was confirmed by infrared spectroscopy.     

电沉积含氟羟基磷灰石/纳米二氧化钛复合涂层的表征与性能研究

根据含氟羟基磷灰石(FHA)陶电沉积瓷技术,将纳米二氧化钛微粒加入电解液中,在钛基体表面进行电化学复合共沉积,获得了含氟羟基磷灰石复合纳米TiO2涂层(FHA/n-TiO2).对FHA/n-TiO2纳米复合涂层进行了真空烧结处理,并通过X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(IR)、X射线光电子能谱(XPS...     

热处理对钛基体表面电泳沉积GO/HA生物活性涂层的影响

采用电泳沉积法在钛基体表面制备氧化石墨烯(GO)/羟基磷灰石(Ca₁₀(PO₄)₆(OH)₂, HA)复合涂层,通过XRD和SEM等测试手段对不同热处理条件下得到的GO/HA涂层进行表征。研究结果表明,热处理有助于促进涂层中HA结晶度的提高,600 ℃和800 ℃的热处理温度并没有导致HA发生热分解,但有可能破坏了涂层中GO的有序晶体结构。GO/HA涂层具有优异的生物活性,但随热处理温度的升高,涂层的润湿性和生物活性下降。热处理过程有利于涂层致密,加强涂层与基体的结合,800 ℃热处理后的涂层结合强度高达25.31 MPa。     

Adhesion of electrochemically formed polypyrrole coatings to low carbon steel

The lap shear strength of polypyrrole coatings formed on low carbon steel (～ 23 MPa) is shown to be significantly higher (by ～ 60%) than that obtained using uncoated steel as the adherend. The lap shear (adhesion) strength of polypyrrole‐coated steel varied with the pH of the monomer–electrolyte solution and the applied current. The low carbon steel‐containing polypyrrole coatings formed at low pH (pH ≤ 2.4) have higher adhesion strength than those coated with polypyrrole at higher pH (pH ≥ 6.0). However, poly(N‐methyl pyrrole)‐coated steel showed significantly lower adhesion strength. Increasing the applied current density decreased the adhesion strength. The surface free energies of polypyrrole coatings, ～ 49–53 mJ/m² are similar to that obtained for uncoated low carbon steel, ～ 53 mJ/m², indicating that polypyrrole will effectively wet low rbon steel. The extent of wetting of low carbon steel by the coatings was additionally confirmed by an interaction parameter, ?, of unity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2757–2763, 2002     

Binder effect on cycling performance of silicon/carbon composite anodes for lithium ion batteries

The cycling performance of a silicon/carbon composite anode has been significantly enhanced by using acrylic adhesive and modified acrylic adhesive as binder to fabricate the electrodes for lithium ion batteries. The capacity retentions of Si/C composite electrodes bound by acrylic adhesive and modified acrylic adhesive are 79% and 90% after 50 cycles, respectively. These two binders are electrochemically stable in the organic electrolyte in the working window. They also show larger adhesion strength between the coating and the Cu current collector as well as smaller solvent absorption in the electrolyte solvent than polyvinylidene fluoride (PVDF). Furthermore, sodium carboxyl methyl cellulose (CMC) plays an important role on improving the properties of acrylic adhesive, which increases the adhesive strength of acrylic adhesive and improves the activation of the electrodes.     

Fabrication of Ti/TiO2(Ca)/hydroxyapatite bioceramic material by micro-arc oxidation and electrochemical deposition

Titanium with a bioceramic hydroxyapatite (HA) coating has been widely used in biomaterials owing to its excellent mechanical characteristics and high osteoconductivity. However, the interfacial strength of Ti/HA prepared by electrochemical deposition (ED) is relatively low because the physical combination is typically inadequate. In this study, to improve the interfacial strength, a micro-arc oxidation (MAO) process with calcium was introduced for preparing a connecting interlayer known as the MAO coating. Pulsed ED was employed to synthesise the HA coating on the MAO surface using an electrolyte with 6 wt% H₂O₂. Sample characterisations revealed that the MAO coating comprised porous TiO₂ (rutile and anatase) with Ca or CaTiO₃. The formation of CaTiO₃ depends on the current density, reaction time, and concentration of Ca²⁺, in addition to voltage. The MAO coatings exhibited a higher corrosion resistance than that exhibited by Ti substrates. Furthermore, the HA coating on the MAO coating was confirmed to be plate-like Ca-deficient HA. The final sample had a Ti/TiO₂(Ca)/HA structure, and its adhesive strength was approximately double that of the Ti/HA sample. In particular, the MAO coating synthesised at a high Ca²⁺ concentration exhibited an improved adhesive strength (2.326 MPa). The application of the MAO coating containing Ca as a connecting interlayer is a promising strategy for improving the HA adhesion strength.     

干喷湿纺法PAN基碳纤维表面处理的研究

以碳酸氢铵为电解质,对干喷湿纺法PAN基碳纤维进行了连续表面处理。通过扫描电子显微镜（SEM）分析其微观结构,同时利用万能材料实验机研究碳纤维及其复合机理。结果表明,随着处理电流密度的增大,碳纤维抗拉强度呈降低趋势。电化学处理碳纤维,电流密度最佳范围应为43．6A·m-^2～54．4A·m^-2,且碳纤维表面官能团对提高复合材料的层间剪切强度起关键作用。     

Formation of polypyrrole coatings onto low carbon steel by electrochemical process

Thin polypyrrole coatings (∼ 10 μm thick) were formed on low carbon steel by an aqueous constant current electrochemical polymerization using oxalic acid as the electrolyte. The amount of polypyrrole coatings formed on steel increased with the applied current and monomer concentration. No significant change in the electropolymerization of pyrrole occurred as a result of increased electrolyte concentration. The induction time for electropolymerization decreased significantly with current density but was unaffected by the initial monomer and electrolyte concentration. The electropolymerization potential of pyrrole increased with increased current density (Cd), i.e., Ep = 0.62 + 0.41 [Cd], and decreased exponentially with increased monomer and electrolyte concentration, Ep = E₀ exp^-[M]. Scanning electron microscopy (SEM) showed that the microstructure of the polypyrrole coatings formed on steel was dependent on the current density to the extent that smoother and more uniform coatings are formed at low current density. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:417–424, 1997     

Effects of carbon nanotube content on adhesion strength and wear and corrosion resistance of epoxy composite coatings on AA2024-T3

The effects of multiwalled carbon nanotube (MWCNT) content on the adhesion strength and wear and corrosion resistance of the epoxy composite coatings prepared on aluminum alloy (AA) 2024-T3 substrates were evaluated using atomic force microscopy (AFM), blister test, ball-on-disk micro-tribological test and electrochemical impedance spectroscopy (EIS). The adhesion strength of the epoxy composite coatings improved with increasing MWCNT content. Increased MWCNT content also decreased the friction coefficient and increased the wear resistance of the epoxy composite coatings due to improved solid lubricating and rolling effects of the MWCNTs and the improved load bearing capacity of the composite coatings. Finally, EIS indicated that increased MWCNT content increased the coating pore resistance due to a decreased porosity density, which resulted in an increase in the total impedance of the coated samples.