Cathodic Electrolytic Deposition Research Articles

Silk-Fibroin-Assisted Cathodic Electrolytic Deposition of Calcium Phosphate for Biomedical Applications

The biological responses of artificial biomaterials are affected strongly by its interfacial topography, especially from nano- to microscale. The structure controllability is essential for the design and synthesis of novel biomedical materials. Herein, the effect of soluble silk fibroin (SF) on the cathodic electrolytic deposition (ELD) behavior of octacalcium phosphate (OCP) coating is studied. It is observed that the addition of soluble SF does not change the inorganic phase of the coating (OCP), but it has a remarkable effect on the microstructure of the deposited coating. As a result, the OCP/SF composite coating possessed a micro/nano multilevel structure is finely constructed on titanium implant by using ELD technology. Such OCP/SF composite coating significantly promotes preosteoblast cells adhesion, spreading and proliferation. In general, effects have been made to produce an in-depth understanding of protein incorporated ELD technology to extend its application in the biomedical field. It provides a promising strategy to design and synthesize biomaterials with specific biomimetic structures and functions.

The effect of cerium pre-treatment on the corrosion resistance of steel sheets

The steel samples have been coated with cerium layer by cathodic electrolytic deposition from the Ce(NO3)3·6H2O solution in aqueous ethyleneglycol in the presence of hydrogen peroxide. The influence of the coating parameters (cathodic current density, pH, cerium concentration, hydrogen peroxide concentration, temperature, and treatment duration) on the surface properties; the optimum conditions of the formation of corrosion preventing coating have been elucidated. Hydrogen peroxide concentration and pH are the major factors influencing the deposition process. The corrosion resistance has been further enhanced after treatment with Na3PO4·12H2O solution. The cerium-coated samples have been subsequently coated by cathodic electrostatic deposition from the colloidal solution of the paint. The coated materials have been subjected to mechanical testing (hardness, impact, cross cut, bending, and cupping tests), and their structure has been visualized by electron microscopy. The cerium coating has been found to improve the steel corrosion resistance by 15%.

Electrodeposition of cerium oxide films and composites

Nanostructured CeO2 films were prepared by cathodic electrolytic deposition (ELD) and electrophoretic deposition (EPD). Benzoic acid has been utilized for the dispersion and charging of CeO2 nanoparticles for EPD. The kinetics of ELD and EPD was investigated. Electrodeposition method has been developed for the deposition of poly(2-vinylpyridine) (PVP) films. The thickness of the films was varied in the range of 0.1–3μm. The deposition mechanism was based on the pH increase in the cathodic reactions, electrophoresis of the protonated PVP macromolecules, neutralization of their charge and film formation at the cathode surface. The deposition yield was studied by the quartz crystal microbalance method. Two electrochemical strategies were developed for the fabrication of composite PVP-CeO2 films, which were based on the electrodeposition of PVP and ELD or EPD of CeO2. The composite films were studied by electron microscopy, X-ray diffraction, thermogravimetric and differential thermal analysis. The CeO2 content in the composite films was varied by the variation of bath composition. The deposition methods allowed the fabrication of crack-free PVP-CeO2 films, which provided corrosion protection of stainless steel substrates in aqueous NaCl solutions.

Cathodic electrolytic deposition of ZnO on mild steel

The present paper deals with the deposition and characterisation of zinc oxide coatings on mild steel substrates by cathodic electrolytic deposition via a 0·1M zinc nitrate aqueous solution. The influence of the deposition parameters, such as applied cathodic potential and deposition time, on the growth of oxide coatings was also investigated. The protection efficiency of these coatings on the mild steel was examined by a potentiodynamic polarisation technique in 0·3M NaCl solution (pH = 5·5, T = 25°C). The obtained results showed that the ZnO coatings improve the anticorrosion performance of mild steel.

Electrolytic processing of MgO coatings

MgO coating was formed on nickel superalloy substrate. The coating process consisted of two steps: cathodic electrolytic deposition of MgOH, and heat treatment. The heat treatment was necessary to calcinate and to sinter the deposit. The deposit morphology and composition, before and after heat treatment, were studied by X-ray diffraction and the scanning electron microscopy. The influence of deposition parameters on deposition yields and deposit morphology is studied and discussed.

Cathodic Electrodeposition of Manganese Oxides for Electrochemical Supercapacitors

Manganese oxide films for electrochemical supercapacitors (ES) have been prepared by cathodic electrolytic and electrophoretic deposition. The cathodic reduction of KMnO4 solutions resulted in the formation of manganese oxide deposits. In another approach electrophoretic deposition (EPD) has been utilized for the deposition of manganese oxide nanoparticles prepared by a chemical precipitation method. The films exhibited pseudocapacitive behavior in a potential window of 0-1 V versus SCE in aqueous 0.5 M Na2SO4 and 0.5 M K2SO4 solutions. The deposition methods allowed the formation of porous films which exhibited a specific capacitance (SC) in the range of up to 240 F/g. The SC decreased with increasing scan rate. The films prepared by electrolytic deposition showed higher SC compared to the SC of EPD deposits.

Electrodeposition of Ceria on Stainless Steel for SOFC Interconnect Applications

Cerium-based oxides usually find application as electrolyte for SOFC applications, but can also be considered as potential protective coating of interconnect materials. Films of ceria were obtained on stainless steel via a cathodic electrolytic deposition method, at elevated temperature. The submicronic films were characterized using X-ray diffraction, showing that the cubic phase was directly obtained. Scanning electron microscopy revealed small grain size, and a no-cracked coating. The electrical properties of the ceria films were investigated by impedance spectroscopy measurements.

Promotion of Bioactive and Corrosion Resistance by Electrolytic Piezoelectric Ceramic

Biocompatibility of metallic implants and bone in orthopaedic surgery plays an important role in long-term survivor of the prosthetic implant fixation. However, titanium and its alloys do not bond to bone in the early stage of implantation (<6 months). On the other hand, titanium alloy undergoes electrochemical exchange and releases metallic ions in the physiological environment, which is believed to be the cause of implant failure. Cathodic electrolytic deposition is an important method in ceramic processing. In this paper, the nanocrystalline BaTiO3 coating were prepared by electrolytic deposition process. According to the XRD results, we can clearly identified that electrolytic deposition Barium titanate hydrate gel annealed at 350°C for 1 hr will form to BaTiO3, and its grain size about 4.85 nm. From dynamic cyclic polarization tests, we can found that dense BaTiO3 coated effective improved corrosion resistance of Ti substrate than untreated. From immersion tests, we can found that BaTiO3 exhibited excellent bioactive.

Synthesis of Titania Thin Films by Cathodic Electrolytic Deposition

The cathodic electrodeposition of titania thin films from solutions containing a titanium salt was studied. Titanium tetrachloride was dissolved in an ethanol-water solution with hydrogen peroxide to prepare titanium peroxocomplex solutions. The deposition of the titania precursor on platinum-coated silicon wafer substrates was carried out by electrolysis of the solutions under constant current conditions. The deposits were thermally treated at fixed temperatures in air and then characterized by X-ray diffraction and scanning electron microscopy.

Biomimetic growth of apatite on electrolytic TiO 2 coatings in simulated body fluid

Titanium and titanium alloys for implants have been widely applied to the orthopaedic and dental fields, due to their excellent corrosion resistance, good mechanical properties and biocompatibility. However, the near bioinert and metallic ions release are still the major problems in the clinical failure. For these reasons, modification of biomaterials surface properties, which support bioactivity and corrosion resistance, should be one of the key objectives in the design of the next generation of orthopaedic/dental implants. Cathodic electrolytic deposition of anatase TiO 2 coating has been successfully deposited on pure titanium substrate. After annealed at 300 °C for 1 h, the coating were further condensed into anatase TiO 2, and gradually transformed into rutile TiO 2 at 500 °C. The dynamic cyclic polarization tests indicated that dense and nanocrystalline anatase TiO 2 coated effectively improved corrosion resistance to avoid aggression of fluoride ion. For immersion tests, the matching structure of anatase TiO 2 and apatite may play an important role in the apatite formation ability. Moreover, the cell culture results also indicated that nanocrystalline anatase TiO 2 not only promoted cells differentiation, but also appeared more bioactive while maintaining non-toxicity. Obviously, the materials characteristics such as crystal structure, surface morphology and corrosion resistance may play an important role in the osteointegration.

Synthesis and characterisation of thin cerium oxide coatings elaborated by cathodic electrolytic deposition on steel substrate

Cerium oxide films are widely studied as a promising alternative to Cr(VI) based pre-treatments for the corrosion protection of different metals and alloys. This paper deals with the deposition and characterisation of cerium oxide films deposited onto mild steel substrates by cathodic electrolytic deposition via Ce(III) chloride aqueous and mixed water–ethyl alcohol solutions with and without hydrogen peroxide as a precursor. The major role of this precursor is to increase the deposition rate of the oxide films allowing smooth and adherent hydrated cerium oxide films to be obtained. However, the evolution of the composition of the bath with time leads to a non-reproducibility of the morphology and composition of the thin films. The deposited oxide films are composed of small particles of hydrated Ce(IV) oxide with a significant amount of amorphous phase. In the absence of a precursor, only the mixed water–ethyl alcohol solution permits cerium oxide films to be deposited. The influence of the deposition parameters such as applied cathodic current density, deposition time and composition of the bath was also investigated. The deposits exhibit a quite developed crack network, which is highly dependent on the deposition parameters and the drying process. Moreover, the incorporation of chloride ions during the deposition has been observed. The protection efficiency of these films was examined during extended immersion tests in 3% NaCl solution. The deposits allow the cathodic reaction kinetics to be reduced by acting as a cathodic inhibitor. However, the presence of large defects or cracks induces an accelerated local degradation of the steel substrate, removing partially the oxide deposit, whereas a thin crack network can rapidly be sealed by corrosion products without deterioration of the deposit.

Electrolytic Deposition of Oxide coatings for Solid Oxide Fuel Cell Interconnects

Composite yttria-silver coatings and praseodymia coatings were applied to 430 stainless steel by cathodic electrolytic deposition. Crack-free 0.5-1 μm thick coatings were obtained from chloride salts in aqueous or water-ethanol solutions. The electrical conductivity and oxidation behavior at 750°C of coated and uncoated samples were investigated. Coated samples oxidized for 24 h developed a scale thickness of approximately 1 μm and an area-specific resistance (ASR) of less than 0.1 ohm.cm 2 , compared to uncoated samples which had a scale thickness near 1.3 μm and an ASR near 0.2 ohm.cm 2 . The scale growth followed parabolic oxidation kinetics up to 168 h, spalling of the scale was evident. Another group of coated samples was initially heated in intermittent steps to 750 C over a period of hours. These samples showed better oxidation performance with good scale adhesion and had a scale thickness of less than 0.1 μm and an ASR of less than 0.1 ohm.cm 2 .

Cathodic electrolytic deposition of zirconia films

Cathodic electrodeposition of composite zirconia-poly(diallyldimethylammonium chloride) (PDDA) films was performed from ZrOCl 2 solutions in a mixed methanol–water solvent containing PDDA. The electrodeposition method is based on the electrosynthesis of zirconia and electrophoresis of PDDA. The method enables the room-temperature electrosynthesis of crystalline zirconia nanoparticles in the polymer matrix. The crystallinity and particle size of zirconia are influenced by the solvent and PDDA. The use of PDDA allowed to prevent cracking attributed to drying shrinkage and obtain thick and adherent films. Sintering at 800 °C resulted in the burning out of PDDA and the formation of tetragonal zirconia films. Obtained deposits were studied using scanning and transmission electron microscopy (SEM and TEM, respectively), atomic force microscopy (AFM), thermogravimetric (TG) analysis and X-ray diffraction (XRD) analysis. The mechanism of deposition is discussed.

Cathodic micro-arc electrodeposition of yttrium stabilized zirconia (YSZ) coatings on FeCrAl alloy

The formation of ceramic coatings on metal substrate by cathodic electrolytic deposition (CELD) has received more attention in recent years. But only thin films can be prepared via CELD. Yttrium stabilized zirconia (YSZ) ceramic coatings were deposited on FeCrAl alloy by a novel technique—cathodic micro-arc electrodeposition (CMED). The result shows that, when a high pulse electric field is applied to the cathode which was pre-deposited with a thin YSZ film, dielectric breakdown occurs and micro-arc discharges appear. Coatings with reasonably thickness of ∼300 μm and crystalline structure can be deposited on the cathode by utilizing the energy of the micro-arc. The thickness of the as-deposited coating is dominated by the voltage and the frequency. Y2O3 is co-deposited with ZrO2 when Y(NO3)3 was added to the electrolyte, which stabilize t-phase, t′-phase and c-phase of ZrO2 at room temperature. The amount of the m-ZrO2 in the coating is diminished by increasing the concentration of Y(NO3)3 in the electrolyte. This report describes the processing of CMED and studies the microstructure of the deposited YSZ coatings.

Synthesis and Magnetic Properties of Ni-Zirconia Composites

A novel method has been developed for the fabrication of composite magnetic films on various conductive substrates. Cathodic electrolytic deposition was used as the technique to obtain thin films from solutions of nickel and zirconium salts. The hydroxide deposits were converted to Ni-ZrO2composites after sintering in reducing conditions. Deposit yield was studied in the constant current deposition mode. Deposits were evaluated using X-ray analysis and magnetic measurements. Results of dc and ac measurements performed in different magnetic fields, temperatures, and frequencies demonstrated the magnetic properties of the composites.

Cathodic Electrodeposition of Ceramic Coatings for Oxidation Protection of Materials at Elevated Temperatures

Cathodic electrophoretic and electrolytic deposition have been utilized for preparation of ZrO2 and CeO2 coatings on stainless steel and graphite substrates. Thick coatings were obtained by multiple deposition or using electrochemical intercalation of a polyelectrolyte into the ceramic deposits. The use of poly(diallyldimethylammonium chloride) as an additive in bath formulation enabled coagulation of ceramic particles near the cathodic substrates to form adherent green deposits with enhanced resistance to cracking. The mechanisms of electrodeposition are discussed. Electron microscopy, thermogravimetric analysis and X-ray diffraction methods are used to examine the microstructure, composition and crystallization behaviour of the deposits prepared under various experimental conditions. Weight gain tests showed that sintered coatings provided good oxidation protection to stainless steel substrates at elevated temperatures.

Cathodic Electrodeposition of Ceramic Coatings for Oxidation Protection of Materials at Elevated Temperatures

Cathodic electrophoretic and electrolytic deposition have been utilized for preparation of ZrO2 and CeO2 coatings on stainless steel and graphite substrates. Thick coatings were obtained by multiple deposition or using electrochemical intercalation of a polyelectrolyte into the ceramic deposits. The use of poly(diallyldimethylammonium chloride) as an additive in bath formulation enabled coagulation of ceramic particles near the cathodic substrates to form adherent green deposits with enhanced resistance to cracking. The mechanisms of electrodeposition are discussed. Electron microscopy, thermogravimetric analysis and X-ray diffraction methods are used to examine the microstructure, composition and crystallization behaviour of the deposits prepared under various experimental conditions. Weight gain tests showed that sintered coatings provided good oxidation protection to stainless steel substrates at elevated temperatures.

Cathodic electrodeposition of polymer films and organoceramic films

Cathodic electrolytic deposition has been utilized for the preparation of polyvinyl alcohol films and organoceramic films based on poly(diallyldimethylammonium chloride) and Zr, Ce, Gd hydroxides. Films of various thicknesses were deposited on Ni, porous Ni-zirconia cermet and La 0.8Sr 0.2Fe 0.8Co 0.2O 3− y ceramic substrates prepared by tape casting. By varying the current density, deposition time and concentration of additives, the amount of the deposited material could be controlled. The morphology of the films was studied by scanning electron microscope. Such films could be used in the fabrication of solid oxide fuel cell laminates.

Electrolytic and electrophoretic deposition of CeO 2 films

Cerium oxide films of thickness 0.1–300 μm were deposited on Ni substrates via cathodic electrolytic and electrophoretic deposition. The films were studied by X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Experimental results obtained by both deposition methods are compared. The influence of deposition parameters and additives on deposition yields and film morphologies is studied and discussed.

Electrolytic deposition of niobium oxide films

Cathodic electrolytic deposition of Nb2O5 films on platinum substrates was performed via hydrolysis by use of an electrogenerated base of the NbCl5 salt dissolved in water in the presence of hydrogen peroxide. The deposits were characterized by XRD, TG/DTA, SEM and Auger methods. The crystallization behavior of the deposits and precipitated gels was compared. A possible mechanism of electrodeposition is discussed.