电化学沉积羟基磷灰石过程晶体生长行为

采用恒电流电化学沉积方法从含钙与磷盐水溶液中直接在纯金属钛电极表面沉积纳米羟基磷灰石涂层,运用EDS、SEM、XRD、FTIR等方法对其进行表征. 重点考察了一种典型制备条件下钙磷沉积层的形貌、结构及组分随沉积时间的变化,进而探讨相应条件下电化学沉积羟基磷灰石涂层晶体生长过程的基本规律. 研究表明电化学沉积法可用于在医用金属表面直接涂覆含钙离子缺陷的纳米羟基磷灰石涂层,典型条件下涂层的生长规律为: (1)沉积过程中羟基磷灰石晶粒以c轴方向沿沉积面法线方向择优生长,且这一趋势延续整个沉积过程; (2)内层晶粒的生长受到外层晶粒生长的抑制, 对于同层的晶粒,当晶粒分布密集时,晶粒生长可能发生相互制约; (3)随沉积时间的延长,沉积量增加,而膜层的化学组成基本不发生变化.     

脉冲电化学沉积法制备羟基磷灰石/壳聚糖复合涂层的研究

采用脉冲电化学沉积法在钛金属表面制备出羟基磷灰石/壳聚糖(HA/CS)复合涂层,实现CS与HA在微观尺寸上的复合与杂化.比较了脉冲电位与恒电位模式下复合涂层的形成,研究了电位高低及壳聚糖浓度对复合涂层性能的影响.结果表明,与恒电位模式比较,脉冲电位下制备的涂层较均匀、结晶性好、CS含量高,并且HA与CS杂化程度高.脉冲...     

原位复合法制备层状结构的壳聚糖/羟基磷灰石纳米材料

用原位复合法制备了高性能的壳聚糖/羟基磷灰石(CS/HA)纳米复合材料.用预先沉积的壳聚糖膜将含有羟基磷灰石前驱体的壳聚糖溶液与凝固液隔离,同时控制壳聚糖沉积与羟基磷灰石前驱体转化为羟基磷灰石的过程,使其缓慢且有序地进行.当pH值改变时,质子化的壳聚糖分子链在负电层诱导下有序沉积并形成层状结构与羟基磷灰石原位生成CS/HA,并实现二者分子级复合.XRD和TEM测试证实原位生成的磷酸盐是羟基磷灰石,且其颗粒长约为100nm,宽30～50nm.SEM结果表明,用原位复合法制备的材料具有层状结构,CS/HA(质量比100/5)纳米复合材料弯曲强度高达86MPa,比松质骨的高3～4倍,相当于密质骨的1/2,有望用于可承重部位的组织修复材料.     

羟基磷灰石/氧化锆复合涂层的水热电沉积及其性能

羟基磷灰石/氧化锆复合涂层的水热电沉积及其性能;水热电沉积;羟基磷灰石;ZrO2;结合强度;生物活性     

电化学沉积含纳米银羟基磷灰石涂层及抗菌性能研究

应用柠檬酸钠还原法制得纳米银胶体溶液,并在钛基表面电泳沉积纳米银颗粒,再由电化学沉积法沉积羟基磷灰石涂层.X射线电子能谱(XPS)、X射线衍射(XRD)和高分辨透射电子显微镜(HRTEM/SEM)证实该涂层含羟基磷灰石(HAp)和Ag,其纳米银颗粒尺度为5~20 nm.抗菌试验表明,涂层中含银量随电泳沉积液纳米银粒子浓度升高而增加,抗菌性也相应增强.但如沉积液中银粒子超过一定浓度时,则其在钛表面会发生明显团聚,导致抗菌性能的降低.据此,初步优化了抗菌效果最佳的复合涂层制备技术.     

电沉积PAMAM/羟基磷灰石复合涂层的研究

电沉积PAMAM/羟基磷灰石复合涂层的研究;羟基磷灰石;聚酰胺胺树枝形聚合物;双电位阶跃技术;电沉积;生物活性     

电化学共沉积HA/胶原复合涂层及其生物性能初探

应用电化学恒电流共沉积法在医用纯钛基底上制备羟基磷灰石(HA)/胶原(collagen)复合涂层.SEM和XPS等测试表明:复合涂层呈特定有序的纳-微米二级多孔结构,化学组分为HA和胶原的有机-无机复合.借助体外细胞的培养实验观察种植于不同材料表面的细胞贴壁及生长形态,显示电化学共沉积的复合涂层具有比纯HA或纯钛表面更好的生物相容性.     

Ti阳极上电沉积制备Pb-聚丙烯腈-碳化钨复合镀层及其电化学性能

通过在酒石酸钾钠体系中加入聚丙烯腈（PAN）、碳化钨（WC）和PbO固体颗粒,在Ti阳极上电沉积制得Pb-PAN-WC复合镀层。 主要研究了电沉积工艺条件(电流密度、温度等)对Pb-PAN-WC复合镀层沉积速度及析氧动力学参数的影响。 在ZnSO4-H2SO4体系中测定的阳极极化曲线表明,最佳工艺条件及固体颗粒加入量为：电流密度1.5 A/dm2,温度35 ℃,15 g/L的PAN,40 g/L的WC。 通过和纯铅镀层的阳极极化曲线和析氧动力学参数对比可知,Pb-PAN-WC复合镀层的电化学性能优于纯铅镀层。     

电化学法制备生物活性陶瓷材料研究

利用电化学方法可以在温和条件下制备生物活性陶瓷涂覆层，从而避免了高温喷涂引起的相变和脆裂，并可在形状复杂的基底上得到均匀的沉积层．因此，近年来在金属表面电沉积生物活性陶瓷涂覆层的研究方面已引起高度重视［’－‘j，然而，目前大多数文献报道所采用的恒电位方法，在沉积过程中电极表面的喊度会发生较大的变化，难以得到组分均匀的沉积层．本文报道用恒电流模式在Ti－6A14V合金表面沉积羟基磷灰石生物陶瓷涂层．1实验部分Ti－6A14V合金为电沉积基底（直径为0．65cm），辅助电极为Pt电极，参比电极采用饱和甘汞电极（SCE）．…     

电沉积羟基磷灰石/TiO2复合涂层

结合强度;电沉积羟基磷灰石/TiO2复合涂层     

脉冲电沉积制备HA/ZrO2纳米复合涂层的稳定性及生物相容性评价

采用脉冲电化学沉积法成功地在生物医用钛金属表面制备出均匀的纳米HA/ZrO₂复合涂层. 通过热处理提高涂层的致密性, 同时保留涂层的微纳结构. 考察了热处理后复合涂层的成分、形貌、生物相容性及生理稳定性. X射线衍射分析表明, 复合涂层成分为HA和ZrO₂. 扫描电镜观察发现, 热处理后复合涂层的致密性有所提高. 研究发现, ZrO₂的加入大大降低了HA/ZrO₂复合涂层中钙离子的释放速度, 提高了HA/ZrO₂复合涂层的生理稳定性. 纳米划痕实验结果表明, HA/ZrO₂复合涂层具有较好的结合强度. 通过培养成骨细胞考察了复合涂层的生物相容性. Alamar Blue检测表明, HA/ZrO₂复合涂层表面细胞黏附及增殖能力较好. ALP检测发现, 热处理后HA/ZrO₂复合涂层表面的细胞分化能力较强. 综合细胞培养结果显示, HA/ZrO₂复合涂层有较好的生物相容性.     

钛基多孔HA/SiO2复合涂层的制备及性能研究

为了制得表面多孔且与基材结合强度高的羟基磷灰石(HA)涂层,实验中以正丁醇为分散介质,以SiO2粉末为添加剂,纯钛片为基材,电泳沉积制备羟基磷灰石/二氧化硅/壳聚糖/(HA/SiO2/CS)复合涂层,经后续热处理得到多孔HA/SiO2复合涂层,采用扫描电镜(SEM)、傅立叶红外光谱仪(FT-IR)、X射线衍射仪(XRD)、万能材料试验机对涂层的表面形貌、组成、结构和结合强度进行测试和表征,并通过模拟体液(SBF)浸泡法对复合涂层的生物活性进行评价.结果表明:当悬浮液中的HA/SiO2/CS质量比为1∶1∶1时,制得的HA/SiO2/CS涂层经700℃热处理后获得的HA/SiO2复合涂层孔洞分布均匀,大孔孔径在10～15μm,小孔孔径在1～5μm;涂层与基材的结合强度达到25.5 MPa;多孔HA/SiO2复合涂层在SBF中浸泡7 d后,涂层表面碳磷灰石化;说明实验中添加SiO2所制得的多孔HA/SiO2复合涂层与钛基材结合强度高,且具有良好的生物活性.     

On the effect of the nature and physical state of a polymer support on the stress-strain characteristics of metallic coatings

A newly proposed microscopic procedure makes it possible to estimate the strength of thin (nano-metric) coatings deposited onto various polymer supports. The strength of the deposited coating is shown to increase dramatically when the thickness of the coating decreases below 15 nm. It was also found that the strength of the coatings is controlled by the physical state of the polymer support. The Interfacial layer formed at the early stages of metal deposition onto the polymer surface is characterized by a higher strength as compared with that of a pure metal deposited onto the above interfacial layer. This observation can be explained by the following reasons: first, the dimensions of metallic grains in the interfacial layer are much smaller than those in a pure metal and, second, the intergrain space in the interfacial layer is filled with polymer matrix. At the same time, both the temperature and the adsorptionally active liquid medium affect polymer partitions in the interfacial composite layer and thus control the overall strength of thin coatings (≤15 nm). In the case of thicker coatings, the strength of the coating gradually decreases independently of the nature and state of the supporting polymer and approaches the strength of the bulk metal.     

Conductivity and electromagnetic shielding effectiveness of flaky Ni/Ni-Cu-coated glass fiber/epoxy resin composite coating

Flaky Ni/Ni-Cu-coated glass fiber/epoxy resin composite coatings were prepared using the glass fibers and flaky nickel powders as fillers and epoxy resin as binder. The conductivity and electromagnetic shielding effectiveness of the coatings are as follows: (1) the appropriate content of Ni-Cu-coated glass fibers is 6 wt % in the composite filler and the optimum ratio of the filler to epoxy resin is 4: 1; (2) electrical conductivity of the coating with a thickness of 300 μm has a minimum value of 0.72 Ω cm; (3) shielding effectiveness of the coatings is up to 50.21–55.43 dB in the frequency range of 0.3–1000 MHz. This offers a new idea to enhance the added value of the glass fibers and raise the level of electromagnetic radiation protection.     

Kinetics of electrodeposition of Ni–ZrO<Subscript>2</Subscript> nanocomposite coatings from methanesulfonate electrolytes

Regularities of incorporation of zirconia nanoparticles into a nickel matrix in the course of electrodeposition of Ni–ZrO₂ coatings from methanesulfonate electrolyte are established. The content of the dispersed phase in coatings grows at an increase in its concentration in electrolyte. Moreover, nanocomposites containing a greater amount of zirconia are deposited from the methanesulfonate electrolyte as compared to sulfate electrolyte. This is explained by the greater partial concentration of ZrO₂ in the solution due to enhanced aggregative stability of the dispersed phase in methanesulfonate electrolyte. The mechanism of formation of the composite coating is considered that is based on the concept of particle incorporation into the metal matrix due to the different rates of metal electrodeposition on the electrode surface free of nonmetallic particles and on the electrode surface conditionally occupied by them. A physically substantiated mathematical model is suggested that describes the kinetics of formation of the composite coating that agrees well with the experimental data.     

Superior corrosion protection and in vitro biocompatibility of Na-HAp/CS composite coating on PoPD-coated 316L SS

The synthesis and development of sodium (Na)-substituted hydroxyapatite (HAp)/chitosan (CS) composite using poly (O-phenylenediamine) (PoPD) coating on 316L SS substrate for improving bioactivity and corrosion protection was studied. The surface of Na-HAp/CS/PoPD bilayer coatings on 316L SS substrate was characterized by diverse analytical techniques. The open circuit potential (OCP) measurement, potentiodynamic polarization, and impedance test revealed that the bilayer coating provides excellent protection to the substrate against the corrosion in the simulated body fluid (SBF) solution. This interior layer of the coating acts as a barrier against the release of metal ions from the substrate, which was confirmed by inductively coupled plasma-atomic emission spectroscopy. Besides, the mechanical properties of the coatings were analyzed. From the obtained results, the bilayer coating exhibited greater mechanical strength than the individual coating. An in vitro bioactivity of the coatings was assessed by immersion in the SBF solution at 7–28 days. The apatite formation of bilayer coatings on 316L SS substrate is found to be more bioactive compared with the Na-HAp, PoPD, and Na-HAp/CS. The in vitro biocompatibility test showed no adverse effects, which was proved by the enhanced biocompatibility of the bilayer coating on 316L SS.     

Metallic film formation using direct micropatterning with photoreactive metal complexes

Palladium, cobalt, and nickel in complex with photoacid-generating ligands, 4-(2-nitrobenzyloxycarbonyl)catechol and 4-(6-nitroveratryloxycarbonyl)catechol, were prepared in solution. Films formed from the metal complex solutions perform as positive-tone, directly photopatternable palladium, cobalt, nickel oxide, or composite film precursors. After exposure, acid-bearing selectively soluble complexes could be removed to give patterned films upon developing in aqueous base, which were transformable to the corresponding pattern-preserving metal/metal oxide film. The photodynamics of photoinduced solubility and direct micropatterning of palladium, cobalt, nickel, and palladium/nickel oxide composite films were investigated. Employing palladium as the initiator for autocatalytic chemical plating, selective direct copper plating on palladium film on polyethylene naphthalate and palladium/nickel oxide composite film on glass was accomplished.     

Physicomechanical properties of nickel coating deposited from sulfate nickel plating electrolyte using preliminary underpotential deposition

A study of nickel coatings electroplated from electrolytes of the compositions (M) NiSO₄ 0.5, NiCl₂ 0.3, and H₃BO₃ 0.404 (electrolyte 1) and NiSO₄ 0.5, NiCl₂ 0.3, and H₃BO₃ 0.404 with the addition of 2 mg L^–1 RADO (electrolyte 2) in the constant-current mode after preliminary potentiostatic treatment (underpotential deposition) of the support revealed the formation of Fe–Ni alloy in the initial moment of formation of the nickel coating. Pretreatment of the steel surface in the underpotential deposition mode allows preparation of uniform finely crystalline nickel coatings with enhanced levels of the wear resistance, microhardness, and corrosion resistance.     

Preparation and Characterization for the Electrodeposited Hybrid Coating of Calcium Phosphate/Chitosan on Ti Alloy Surface

Hydroxyapatite (HA) formulated as Ca₁₀(PO₄)₆(OH)₂ becomes a favorable material for implants because of its chemical similarity to the calcium phosphate minerals present in biological hard tissue. Many efforts have been made in recent years in the development of processing methods for depositing hydroxyapatite on implant alloy substrate in order to have high strength, good processability, suitable specific density, excellent corrosion resistance in the physiological environment and good affinity to the living body. The plasma spray technique is commonly used in the HA coating on implants. The major problem for the plasma spray, however, is the decomposition and phase transformation of hydroxyapatite during the spray coating process. Electrochemical techniques including electrophretic deposition and electro-deposition are being developed as an alternative method for producing hydroyapatite coated composite material. It is very desirable at present to further strengthen the coating and bond it to the metal substrate, and to increase the bioactivity of hydroxyapatite coatings as well, which is very important for forming a strong chemical bond with natural bone as an implant material.     

Electrical and optical properties of ceramic–polymer nanocomposite coatings

Transparent, conductive composite coatings were fabricated from suspensions of poly(vinyl acetate‐acrylic) (PVAc‐co‐acrylic) copolymer latices (50–600 nm) and nanosized antimony‐doped tin oxide (ATO) particles (～15 nm). The suspensions were deposited as coatings onto poly(ethylene terephthalate) substrates and dried at 50 °C. Microstructure studies using field emission scanning electron microscopy and tapping‐mode atomic force microscopy (TMAFM) indicated that the latex particles coalesced during drying and forced the ATO particles to segregate into the boundaries between the latex particles. Low phase contrast was observed with TMAFM; this result was consistent with the presence of PVAc‐co‐acrylic in the ATO‐rich phase of the composite. The conductivity of the composite coatings followed a percolation power‐law equation, with the percolation threshold between 0.05 and 0.075 volume fractions of ATO and the critical conductivity exponent ranging from 1.34 to 2.32. The highest direct‐current conductivity of the composite coatings was around 10^?2 S/cm. The optical transmittance and scattering behavior of the coatings were also investigated. Compared with the PVAc‐co‐acrylic coating, the composite coatings had lower transparency because of the Rayleigh scattering. The transparency of the composite coatings was improved by a reduction in the coating thickness. The best transparency for the coatings with a direct‐current conductivity of approximately 10^?2 S/cm was around 85% at a wavelength of 600 nm. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1744–1761, 2003