电沉积生物活性陶瓷涂层技术

介绍了电沉积法（包括电泳沉积EPD和电化学沉积ECD）在Ti或Ti合金基体上制备生物活性陶瓷涂层HAP的制备工艺,评述了电沉积的主要控制参数,总结了该技术的特点并展望了其应用前景。     

Electrophoretic deposition of carbon nanotubes–hydroxyapatite nanocomposites on titanium substrate

Carbon nanotubes–hydroxyapatite (CNTs–HA) composites were synthesized, using an in situ chemical method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were uniformly absorbed on the CNTs, with strong interfacial bonding. The CNTs–HA composites behaved like single composites when deposited on a titanium substrate by electrophoretic deposition (EPD). EPD was carried out at 10, 20 and 40 V, for 0.5 to 8 min at each voltage. Coating efficiency and weight increased with increasing deposition time, while the slope of the curves decreased, indicating a decrease in deposition rate. The CNTs–HA coating morphology was analyzed with scanning electron microscopy (SEM). The results revealed that decreasing the voltage used for deposition coatings could reduce cracking frequency. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies showed that the deposition coatings protected the titanium substrate from corroding in simulated body fluid (SBF). In addition, in vitro cellular responses to the CNTs–HA coatings were assessed to investigate the proliferation and morphology of osteoblast cell line.     

Electrophoretic deposition of functional organic molecules and composite films

2,2′-Bicinchoninic acid (BiqCOOH) exhibits a set of functional properties, which motivated the work of fabricating BiqCOOH films. Thin films of BiqCOOH were prepared potentiodynamically or under constant-voltage conditions from the solutions of dipotassium salt of 2,2′-bicinchoninic acid (BiqCOOK) in water or ethanol-water solvent. Electron microscopy investigations showed that the electrochemical assembly of BiqCOOH in aqueous solutions resulted in fibrous morphology while a flower-like morphology, containing rectangular prism-shaped particles, was the result in ethanol-water solutions. The anodic deposition mechanism for BiqCOOH has been proposed based on the analysis of cyclic voltammetry (CV), electron microscopy and FTIR data. The polyaromatic BiqCOOK molecules, containing chelating ligands, showed adsorption on a range of different materials, such as Pd, NiO and multi-walled carbon nanotubes (MWCNT). An electrophoretic deposition (EPD) method allowed for the manufacturing of Pd, NiO and MWCNT films using BiqCOOK as anionic dispersing and binding species. The results of this investigation have generated new possibilities in creating individual material and composite films for applications based on their functional properties.     

Use of electrophoretic deposition in the processing of fibre reinforced ceramic and glass matrix composites: a review

Electrophoretic deposition (EPD) is a simple and cost-effective method for fabricating high-quality ‘green’ composite bodies which, after a suitable high-temperature treatment, can be densified to a composite with improved properties. In this contribution, we describe the use of EPD technique in the fabrication of fibre reinforced composites, with an emphasis on composites with glass and ceramic matrices containing metallic or ceramic fibre fabric reinforcement. EPD has been used to infiltrate preforms with tight fibre weave architectures using different nanosized ceramic particles, including silica and boehmite sols, as well as dual-component sols of mullite composition. The principles of the EPD technique are briefly explained and the different factors affecting the EPD behaviour of ceramic sols and their optimisation to obtain high infiltration of the fibre preforms are considered. In particular, the EPD fabrication of a model alumina matrix composite reinforced by Ni-coated carbon fibres is presented. The pH of the solution and the applied voltage and deposition time are shown to have a strong influence on the quality of the infiltration. Good particle packing and a high solids-loading were achieved in most cases, producing a firm ceramic deposit which adhered to the fibres. Overall, the analysis of the published data and our own results demonstrate that EPD, being simple and inexpensive, provides an attractive alternative for ceramic infiltration and coating of fibre fabrics, even if they exhibit tight fibre weave architectures. The high-quality infiltrated fibre mats are suitable prepregs for the fabrication of advanced glass and ceramic matrix composites for use in heat-resistant, structural components.     

Electrochemical Deposition of Composites Using Deoxycholic Acid Dispersant

A biomimetic method has been used for the electrodeposition of carbon nanotubes (NTs) and composite films using a commercial bile acid. Thin films of deoxycholic acid (DCH) were prepared potentiodynamically and galvanostatically from deoxycholic acid sodium salt (DCNa) solutions. The anodic deposition yield has been investigated at different DCNa concentrations. The electrodeposition mechanism involved electromigration of anionic DC^? species, local pH reduction at the anode, and precipitation of DCH. It was found that DCNa allowed excellent dispersion of NTs in water. The use of DCNa as a multifunctional agent for NTs dispersion, charging, and binding allowed electrodeposition of NTs and composite MnO₂–NTs films. The MnO₂–NTs composites were used for charge storage applications in supercapacitors. The MnO₂–NTs electrodes showed good capacitive behavior. DCNa is a promising charging dispersant for NTs dispersion and manufacturing of other composites by electrochemical methods.     

The preparation of LPS SiC-fibre-reinforced SiC ceramics using electrophoretic deposition

With the aim of determining the possibility of producing SiC-based ceramic-matrix composites using the electrophoretic deposition (EPD) technique, the effect of the composition of SiC-based suspensions on the deposition was studied. Ethanol suspensions of two different grades of SiC powders, with and without the addition of a sintering aid, were used for depositing on steel electrodes or on SiC-fibres. The pH of the suspensions, the solids loading and the particle size were shown to have a strong influence on the deposition process and on the properties of the fresh deposits. The overall results demonstrate that by using appropriate conditions for the EPD, a firm SiC-based deposit can be collected at the SiC-fibres and after suitable thermal treatment, a pore-free SiC-matrix, well adhered to the SiC fibres, can be achieved.     

Electrophoretic deposition infiltration of 2-D metal fibre-reinforced cordierite matrix composites of tubular shape

Stainless steel (316L) fibre mats shaped into tubular geometry were used to reinforce cordierite. The ductile phase-reinforced cordierite matrix composites were manufactured by using electrophoretic deposition (EPD) and pressureless sintering. An EPD cell suitable for the fabrication of tubular composites was designed. The relevant process parameters required to infiltrate the fibre mats with nanosized cordierite powders and to obtain homogeneous electrophoretic cordierite deposits on the inner and outer surfaces of the fibrous substrate were optimised. EPD experiments were conducted under constant voltage conditions (5 V dc) with varying deposition times. The sintered composites having internal and external deposit thickness of about 1 mm were free of surface cracks when a deposition time of 2.5 min was used. The developed metal fibre reinforced cordierite composites may constitute a promising alternative for manufacturing damage-tolerant tubular components for applications at intermediate-temperatures (up to 900°C).     

Au-Pt纳米颗粒/石墨烯-纤维素微纤维复合电极的制备与电化学性能

石墨烯和金属纳米是优异的导电纳米材料,为构建具有高效活性表面积的电化学传感界面,以玻碳电极作为导电基底,采用滴涂法结合一步电沉积成功制备了Au-Pt纳米颗粒/还原氧化石墨烯-纤维素微纤维(Au-Pt NPs/RGO-CMF)复合材料。SEM、原子力显微镜(AFM)、EDS和拉曼光谱分析表明,Au-Pt纳米颗粒均匀分布在RGO-CMF的薄层上,同时实现了氧化石墨烯(GO)还原为RGO。以铁氰化钾作为氧化还原探针对界面的电化学性质进行研究,在优化的实验条件下(循环伏安法电沉积:电位为?1.2~0 V,周期为20,电解质pH值为6,滴涂GO-CMF体积为8 μL),得到Au-Pt NPs/RGO-CMF复合材料的高效活性表面积(3.54 cm2)远远优于裸玻碳电极(1.52 cm2)。表明构建界面具有高的电催化活性,为传感器的进一步应用提供理论支持。      

Electrodeposition of Carbon Nanotubes Triggered by Cathodic and Anodic Reactions of Dispersants

The combination of advanced functionalization methods for surface modification and dispersion of carbon nanotubes (CNTs) and electrochemically triggered strategies for coagulation and film formation allowed efficient electrodeposition of CNTs by cathodic and anodic methods. The electrochemical methods involved the application of cationic basic fuchsin or anionic fluorescein dyes. The dyes adsorbed on CNTs provided electrosteric dispersion. The film forming and binding properties of the dyes and their charge neutralization in electrode reactions promoted deposit formation. The proposed methods allowed controlled electrodeposition of CNT films.     

电化学方法制备金属基复合材料研究进展

金属基复合材料具有高比强度、高比模量、高硬度、耐高温等一系列优点,在现代航空、航天及武器装备等领域具有广阔的应用前景.综述了近年来电化学方法制备金属基复合材料的研究进展,具体介绍了电化学渗浸、连续分步电沉积和复合电沉积3种不同的电化学工艺过程.     

Electrodeposition of macroporous magnetic metal films using colloidal nickel phosphate templates

Two-dimensional (2D) and three-dimensional (3D) macroporous nickel based films with randomly distributed spherical pores (diameter 90-210 nm) were synthesized by a simple templated electrodeposition route. Porous templates on Sn doped In₂O₃ (ITO) coated glass were constructed via electrophoretic deposition (EPD) of colloidal nickel phosphate particles prepared by a homogeneous precipitation method. The infilling of metal was sequently carried out in an electrodeposition bath, and porous films were obtained by dissolving the templates in ammonium sulfate solution. By adjusting the deposition charge, the thickness of the porous films could be controlled from 100 nm to tens of microns. Room temperature magnetic properties of the porous films were studied, remarkably enhanced coercivity and squareness than that of corresponding plain films were observed.     

Three-dimensional heterostructured MnO2/graphene/carbon nanotube composite on Ni foam for binder-free supercapacitor electrode

In this article, three-dimensional (3D) heterostructured of MnO₂/graphene/carbon nanotube (CNT) composites were synthesized by electrochemical deposition (ELD)-electrophoretic deposition (EPD) and subsequently chemical vapour deposition (CVD) methods. MnO₂/graphene/CNT composites were directly used as binder-free electrodes to investigate the electrochemical performance. To design a novel electrode material with high specific area and excellent electrochemical property, the Ni foam was chosen as the substrate, which could provide a 3D skeleton extremely enhancing the specific surface area and limiting the huge volume change of the active materials. The experimental results indicated that the specific capacitance of MnO₂/graphene/CNT composite was up to 377.1 F g^?1 at the scan speed of 200 mV s^?1 with a measured energy density of 75.4 Wh kg^?1. The 3D hybrid structures also exhibited superior long cycling life with close to 90% specific capacitance retained after 500 cycles.     

Alternative Uses of Waste Glasses: Issues on the Fabrication of Metal Fibre Reinforced Glass Matrix Composites

In order to investigate a potential use for recycled speciality glasses (specifically those containing hazardous elements), a processing route has been developed for the fabrication of metallic fibre mat reinforced glass matrix composites. Commercially available 3-dimensional stainless steel 316L fibre mats were used as the metal reinforcement, and a borosilicate glass which had been used previously in radiation experiments was used as the glass matrix. The fibre mats were infiltrated with a commercially available silica sol using electrophoretic deposition (EPD), and the glass matrix was laid in between infiltrated fibre mats prior to consolidation using uniaxial cold pressing. It was found that composites with sufficient integrity could be obtained from this recycled waste glass after sintering in air at 850°C for 1 h. The deposited silica remained amorphous at the processing temperature, providing a porous interface between the metallic reinforcement and the waste glass matrix. The processing issues involved in composite fabrication, namely, the EPD infiltration parameters for the silica sol, the quantity and subsequent effect of the impurities present in the waste glass, and the densification of the composite material on sintering, have been discussed.     

汽车内饰用秸秆纤维/聚丙烯复合材料流变本构方程的建立

以秸秆纤维/聚丙烯(PP)母粒和PP为主要原料,利用双螺杆挤出机共混挤出造粒制备了不同纤维含量的汽车内饰用秸秆纤维/PP复合材料。通过对复合材料的压力-比容-温度(PVT)特性和黏度特性进行测试分析,建立了不同秸秆纤维含量的秸秆纤维/PP复合材料的PVT曲线和黏度曲线,探讨了纤维含量对材料PVT特性和黏度特性的影响规律。分别使用修正的双域Tait状态方程和Cross-WLF黏度方程对PVT曲线和黏度曲线进行参数拟合;基于拟合结果的分析,最终建立了考虑秸秆纤维含量影响的修正PVT模型与黏度方程。基于Moldflow分析软件建立了材料属性文件,对某汽车门饰板进行了模流分析。结果表明,建立的复合材料流变方程可有效用于注塑成型数值模拟分析。      

电泳沉积CNTs掺杂C/C复合材料的微观组织与弯曲性能

采用电泳沉积(EPD)在1k碳布表面均匀加载了碳纳米管(CNTs), 借助化学气相沉积(CVD)致密化碳布叠层预制体, 制备了EPD CNTs掺杂的二维(2D)碳/碳(C/C)复合材料。研究了EPD CNTs对2D C/C复合材料致密化过程、微观组织和弯曲性能的影响。研究结果表明: EPD CNTs在碳纤维表面呈现平面内高密度、杂乱取向分布特征, 该形貌CNTs降低了热解炭在碳纤维预制体内的沉积速率, 诱导了高石墨微晶堆垛高度(L_c)、低(002)晶面面内方向上的沉积有序度(L_a)热解炭的形成; EPD CNTs的掺杂可提高C/C复合材料的弯曲强度和模量: 当CNTs含量为0.74wt%时, 复合材料弯曲强度和模量可达150.83 MPa和23.44 GPa, 比纯C/C复合材料提高了31.4%和13.9%; 继续提高CNTs含量, 复合材料弯曲强度降低, 这与过高含量EPD CNTs导致复合材料密度降低有关; 同时, EPD CNTs的掺杂使得C/C复合材料断裂模式由脆性断裂转变为假塑性断裂, 复合材料断裂塑性的提高是由于EPD CNTs造成的碳基体结构的变化以及碳纤维的大量拔出。     

Development of novel bioactive composites by electrophoretic deposition

Electrophoretic deposition (EPD), which is normally available on electric conductive materials, was applied to insulating materials. Wollastonite particles were deposited into the pores of porous alumina and porous ultrahigh molecular weight polyethylene (UHMWPE) substrates by EPD to yield alumina-wollastonite and UHMWPE-wollastonite composites, respectively. These composites were soaked in simulated body fluid (SBF) to evaluate their apatite-forming ability. Apatite was induced from the wollastonite particles, which grew on the surfaces and covered the entire composite surfaces. The bonding strength of the apatite layer to the substrates was as high as 8.9 MPa for alumina and 5.2 MPa for UHMWPE due to an interlocking effect. Thus, the formed alumina-wollastonite and UHMWPE-wollastonite composites should be useful as bone substitutes.     

Studies of the optical properties of metal-pliable polymer composite materials

Polymer-nano-metallic-particle composites have demonstrated technological potential due to their unique optical and electrical properties. Herein, we report on composites prepared via physical vapor deposition of silver metal onto pliable poly(dimethylsiloxane) (PDMS) polymer. Rapid Ag diffusion and nano-metallic-particle formation in a phase-separated surface layer of the PDMS creates unique sub-surface-based composites whose properties vary based on rate of deposition and average Ag thickness. Additionally, nanometallic-particle spacing can be altered with fair reproducibility and reversibility by physically manipulating the Ag-PDMS composite. The optical properties of the materials are studied by visible wavelength optical extinction spectrometry and surface-enhanced Raman scattering (SERS), including studies performed during physical manipulation. Direct current (DC) conductivity measurements were made during Ag deposition to study percolation conditions for the materials. Depth-profiling was performed by X-ray photoelectron spectrometry. Sample Raman spectral data collected with the composite as a SERS substrate are included. A practical technological characteristic of these composite materials arises from their potential to be molded into functional devices.     

Microstructural development of woven mullite fibre-reinforced mullite ceramic matrix composites by infiltration processing

Mullite fibre (Nextel 720?)-reinforced mullite ceramic matrix composites (CMCs) with zirconia weak interface were fabricated from heterocoagulated nano-size boehmite/amorphous silica powder particles dispersed in water, using electrophoretic deposition (EPD) and pressure filtration (PF). The nano-size mullite precursor was first prepared and characterised in terms of short-range particle–particle interactions and particle size distribution. Woven Nextel 720 mullite fibres were first desized and then coated with hydrothermally derived zirconia using dip-coating. EPD was performed under constant voltage conditions with varying deposition times, to infiltrate the dispersed powder suspensions into mullite fibre preforms, enabling the parameters necessary for good deposition of stoichiometric mullite to be established. EPD formed bodies were further consolitated using PF. The EPD/PF prepared green body specimens were dried under controlled atmosphere conditions before being sintered at 1200°C for 2 h in air. Mullite fibre mats were fully infiltrated using EPD parameters of 12 V DC applied voltage with 4 min deposition time, then eight EPD infiltrated fibre mats were further consolidated together using PF. The resulting CMC produced contained 35 vol% fibre loading and showed 81% theoretical density aftersintering at 1200°C for 2 h.     

Superhydrophobic Surfaces by Electrochemical Processes

This review is an exhaustive representation of the electrochemical processes reported in the literature to produce superhydrophobic surfaces. Due to the intensive demand in the elaboration of superhydrophobic materials using low‐cost, reproducible and fast methods, the use of strategies based on electrochemical processes have exponentially grown these last five years. These strategies are separated in two parts: the oxidation processes, such as oxidation of metals in solution, the anodization of metals or the electrodeposition of conducting polymers, and the reduction processed such as the electrodeposition of metals or the galvanic deposition. One of the main advantages of the electrochemical processes is the relative easiness to produce various surface morphologies and a precise control of the structures at a micro‐ or a nanoscale.