Codeposition Of Particles Research Articles

Preserving Anti-Corrosion Properties of Epoxy Based Coatings Simultaneously Exposed to Humidity and UV-Radiation Using Nano Zinc Oxide

Nano zinc oxide-containing epoxy-based coatings were prepared by co-deposition of zinc oxide nano particles and epoxy-based cathodic electrodeposition paint. The films were exposed to UV radiation for different periods and the corrosion resistance properties of the exposed films were evaluated by electrochemical impedance spectroscopy. It was found that the nano zinc oxide stabilized coatings maintain their protective properties even after a prolonged exposure to UV light. The more prolonged retention of protection properties of the coating was assigned to the morphology of the film containing nano ZnO after exposure to UV light. Nano ZnO stabilized coatings show a uniform degradation of the film surface while non-stabilized coating exhibit deep cracks which results in deterioration of the film integrity. UV exposure of non-stabilized films was found to result in formation of deep cracks and non-uniform photodegradation in epoxy coating.

Formation of Electroless Ni-B Coating on Boron Carbide Particles for Composite Processing

The present investigation is on formation of a uniform coating of Ni-B coating on the surface of B4C particle by electroless technique by varying process parameters and pH of the coating bath. The coating characteristics observed on majority of pH conditions on activated particles were mesh-like and at higher pH 12 the coated surface characteristics changes to patch like morphology. At lower alkaline condition there was not enough time for co-deposition to occur and the co-deposits appeared along with the coated particles. The studies with varying pH showed that pH 8 gives uniform coating of the entire particles surface with Ni-B and above which higher amount of co-deposited particles of Ni-B is also observed.

Development and characterization of electro deposited Nickel–Titanium Carbo Nitride (TiCN) metal matrix nanocomposite deposits

The effects of electrochemical parameters on the development of Nickel–Titanium Carbo Nitride (TiCN) metal matrix nanocomposite deposits were studied in Watts type nickel bath. The extent of TiCN incorporation into nickel matrix was studied with respect to TiCN particle concentration ranged between 2 and 15 g l − 1 , current density ranging from 2 to 10 Ad m − 2 , bath pH from 2 to 5 and a bath temperature range of 30–70 °C. Effects of TiCN particle incorporation on surface morphology, crystal structure, micro hardness, wear resistance and corrosion resistance of the composite deposits were studied. It was found that the incorporation of TiCN particles in the composite deposit increased with increasing TiCN content in the bath. Operating the bath with 6 g l − 1 TiCN particle concentrations at 4 Ad m − 2 , at 50 °C, and at pH 4 gave about 23.9 vol.% TiCN incorporation in the composite deposit. The results showed that the codeposition of TiCN particles with nickel modified the surface morphology of nickel and its preferred orientation. The Ni–TiCN composite deposits showed better corrosion resistance in 3.5 wt.% NaCl solution and high hardness and wear resistance than nickel electrodeposited under the same conditions.

Corrosion behavior of Cu–SiO2 nanocomposite coatings obtained by electrodeposition in the presence of cetyl trimethyl ammonium bromide

Copper silica composite coatings are an attractive alternative to chromium and nickel coatings in order to avoid environmental problems and for application in electrical devices. However, co-deposition of SiO2 particles with metals occurs to a rather limited extent, generally under 1%, due to the hydrophilicity of SiO2, which makes the incorporation of particles in a metallic matrix difficult. To overcome this drawback, the influence of cetyl trimethyl ammonium bromide (CTAB) on the deposition and corrosion behavior of Cu–SiO2 coatings on steel has been studied. It was established that CTAB plays a beneficial role in SiO2 suspension stabilization, promotes the co-deposition of nanoparticles in the copper matrix and improves the deposit morphology and structure. Consequently, a higher corrosion resistance of Cu–SiO2 deposits obtained in the presence of CTAB was noticed. The most important effect was observed in the case when CTAB was used in concentration of 10−3 M in the electroplating bath.

Electrodeposition of zinc–silica composite coatings: challenges in incorporating functionalized silica particles into a zinc matrix

Zinc is a well-known sacrificial coating material for iron and co-deposition of suitable particles is of interest for further improving its corrosion protection performance. However, incorporation of particles that are well dispersible in aqueous electrolytes, such as silica particles, is extremely difficult. Here, we report a detailed study of Zn–SiO2 nanocomposite coatings deposited from a zinc sulfate solution at pH 3. The effect of functionalization of the silica particles on the electro-codeposition was investigated. The best incorporation was achieved for particles modified with SiO2–SH, dithiooxamide or cysteamine; these particles have functional groups that can strongly interact with zinc and therefore incorporate well into the metal matrix. Other modifications (SiO2–NH3+, SiO2–Cl and N,N-dimethyldodecylamine) of the silica particles lead to adsorption and entrapment only.

Co-electrodeposition of inorganic fullerene (IF-WS 2) nano-particles with cobalt from a gluconate bath with anionic and cationic surfactants

The codeposition of IF-WS 2 particles (130 nm diameter) in a cobalt matrix has been investigated. The influence of cobalt content and anionic and cationic surfactants on composite coatings produced using direct current (DC) and pulse reverse plating (PRP) are described. The coatings were assessed by XRD, SEM and EDX. The cationic surfactant promoted particle encapsulation and high oxygen content in DC coatings, whilst anionic surfactants do not offer controlled particle codeposition. Improved particle content and distributions were obtained by PRP, on the high cobalt bath containing anionic surfactant. The particle content was optimised by fixing the anodic cycle time t a, and varying the cathodic cycle time, t c. Sound coatings with a high percentage (11 vol.%) of particles were produced at t c of 60 s. This was encouraged by electrophoretic attraction of particles in the anodic phase and then encapsulation during the cathodic phase of the cycle.

Investigation of Ni-YSZ Composite Manufactured by Electroless Ni Coating

Nickel ceramic composite has becoming highly important in mechanical engineering perspective. The paper focused on a newly developed Ni-YSZ composite manufactured by electroless nickel coating. The aims are to ensure good coating with well distributed and high ceramic particle co-deposition. Low metal to ceramic ratio increases nickel ceramic composite resistance to corrosion, wear and thermal. The 2k full factorials design of experiment was used in determining the best EN composite process parameters for high ceramic co-deposition. The composite surface microstructure and characterisation were analysed using scanning electron microscope (SEM) and the Ni composition was measured by SEM coupled with energy dispersive X-ray (EDX).

Wear and corrosion properties of electroless nickel composite coatings with PTFE and/or MoS2 particles

This study focuses on the effect of co-deposition of PTFE and/or MoS2 particles on the morphology, wear, and corrosion properties of electroless nickel coating. The composite coating of EN–PTFE–MoS2 was heat treated at different temperatures for hardness investigations. The surface morphology of coatings was characterized by scanning electron microscopy. Pin-on-disk and potentiodynamic polarization tests were used to study the tribological and corrosion properties of the coatings, respectively. Results of hardness analysis revealed that the hardness of electroless nickel coatings was increased by the heat treatment, and its maximum was gained at 400°C. Wear investigations showed that simultaneous co-deposition of the PTFE and MoS2 particles into the nickel coating increased the wear resistance of the coating by about 30% and reduced the average value of friction coefficient to 0.25 from 0.65. Corrosion studies illustrated that simultaneous co-deposition of the PTFE and MoS2 particles led to reduction in corrosion resistance by 10 and 5 times that of EN coating in brine and acidic solution, respectively.

Effect of stirring rate on the microstructure and microhardness of Ni–CeO2 nanocomposite coating and investigation of the corrosion property

The nickel–ceria nanocomposite coatings have been pulse electrodeposited from a Watts-type electrolyte containing nano-sized ceria particles have been synthesized by high energy ball milling technique. The influence of the stirring rate of the plating bath on the microstructure and hardness of nickel–ceria nanocomposite coating has been investigated and the corrosion property of the nanocomposite coatings has also been studied. Experimental results show that both the co-deposition of ceria particles in the Ni matrix and microhardness of the composite coating increase up to the stirring rate of 450rpm. Beyond this stirring rate the co-deposition of ceria particles decreases in the Ni matrix resulting in a decrease in the hardness of the composite coating. Another reason of decreasing hardness of the composite coating is the agglomerations of ceria particles that take place after the stirring rate of 450rpm. Higher corrosion resistance has been found for the nickel–ceria nanocomposite coating electrodeposited from electrolyte with the stirring rate of 450rpm.

The effect of Cs + ions on codeposition of SiC particles with nickel

Electrodeposition of SiC particles (technical powder) with nickel matrix in the presence of cesium ions (0–37.6 mM) was investigated. The influence of Cs + concentration on cathodic polarization curves was determined in galvanostatic and potentiodynamic measurements. The presence of Cs + in the solution enhanced in some extent adsorption of Ni 2+ ions on SiC, but preferential cesium adsorption occurred simultaneously. The last phenomenon resulted in cesium incorporation in the composite coating. The particle content in the deposits (16–24 vol%) was governed by the amount of nickel ions adsorbed on SiC. Structure of the composite coatings was studied by microscopic observations. At highest Cs + concentrations, incorporation of small SiC grains was inhibited. Microhardness of deposits (390–800 HV) was directly dependent on the SiC content in the coatings.

Co-Deposition of Binary Particles during Slip Casting Process

Co-deposition of silicon carbide particles and carbon (or carbon sources) particles is essential for preparation of reaction bonded silicon carbide (RBSC) products by slip casting. The way of co-depositing of silicon carbide particles and carbon particles during slip casting process, and the influence of composition of raw particles on particle co-depositing in green bodies were studied. The experiment results show: 1.Co-deposition of binary particles is greatly affected by particle size distribution, and large proportion of rigid SiC particles increases the difficulty in demoulding procedure because of small shrinkage; 2. Dispersants in deposited cake trend to enrich at the surface in contact with mould wall, while this enrichment of dispersant has little effect on mechanical performance of RBSC products; 3. Sharp edges on surface of raw particles could result to friction among particles, which afford strength to green bodies but prevent particles packing more closely.

Influence of CTAB cationic surfactant on codeposition of SiC particles with cobalt

Electrodeposition of SiC particles in a cobalt matrix in the presence of cetyltrimethylammonium bromide (CTAB) as a cationic surfactant has been carried out. The inhibiting effect of CTAB (0–1·1 mM) on the cathodic process was observed during the establishment of polarisation curves in galvanostatic and potentiodynamic measurements. The surfactant enhanced SiC incorporation into the matrix from ∼5 vol.‐% in the absence of CTAB to ∼30 vol.‐% at 1·1 mM CTAB for two current densities (0·5 and 1·0 A dm−2). The presence of cationic surfactant in the bath decreased the adsorption of Co2+ ions on SiC, but increased Br− adsorption was simultaneously observed. Current efficiencies were correlated with Co2+/Br− molar ratios for the ions adsorbed on the particles. The structure of the composite coatings was studied microscopically. Microhardness of the deposits (200–500 HV) was also determined.

Codeposition of SiC Particles with Electrolytic Nickel

Codeposition of SiC Particles with Electrolytic Nickel

Electrochemical behaviour of high phosphorus electroless Ni–P–Si3N4 composite coatings

A high phosphorus electroless nickel bath was used to prepare plain Ni–P and composite coatings containing submicrometre size silicon nitride particles. Deposits were characterised for their composition, morphology and electrochemical behaviour. Codeposition of particles in a Ni–P matrix has not influenced the phosphorus content (10 wt-%). Surface morphology of plain Ni–P deposits was smooth; the composite deposits became slightly rough with small nodules due to particle incorporation. Cross-sectional examination of composite coating revealed that the particles were uniformly distributed throughout the thickness of the coating. Potentiodynamic polarisation and electrochemical impedance studies were carried out in 3·5 wt-% sodium chloride solution in non-deaerated condition. Potentiodynamic polarisation studies showed that the corrosion current density value obtained for composite coatings is lower than that for plain Ni–P coatings. Electrochemical impedance spectroscopy studies showed that the coating resistance of the composite coating is higher than that of plain Ni–P coating. This was further confirmed by SEM analysis of corroded samples.

Research of Thermodynamics and Properties of Pb/WC-Zro<sub>2</sub> Inert Electrodes Used in Zinc Electrodeposition

This research is to fabricate a Pb/WC-ZrO2 inert electrode used in zinc electrodeposition. First, the potential-pH diagram of Pb-H2O system was constructed and the thermodynamic stable region was calibrated in the diagram. On the basis, the co-deposition of Pb, WC and ZrO2 particles from fluorboric acid solutions was realized on the surface of Pb-4wt%Sb substrate. The results show that deposition amounts of ZrO2 and WC particles in the inert electrodes increase with increasing ZrO2 concentrations in the bath, WC particle is easier to deposit into the inert electrodes than ZrO2 particle. The distribution of WC and ZrO2 particles as the second phase within metal matrix Pb is very uniform. Compared with Pb-1wt%Ag alloy electrode, Pb/9.91wt%WC-3.62wt%ZrO2 inert electrode possesses better catalytic activity of oxygen evolution.

Electrodeposition of Ni-Co-Fe2O3 composite coatings

Ni-Co-Fe2O3 composite coatings were electrodeposited using cetyltrimethylammonium bromide (CTAB)-modified Watt’s nickel bath with Fe2O3 particles dispersed in it. The effects of the plating parameters on the chemical composition, structural and morphological characteristics of the electrodeposited Ni-Co-Fe2O3 composite coatings were investigated by energy dispersive X-ray (EDS) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results reveal that Fe2O3 particles can be codeposited in the Ni-Co matrix. The codeposition of Fe2O3 particles with Ni-Co is favoured at high Fe2O3 particle concentration and medium stirring, and the deposition of Co is favoured at high concentration of CTAB. Moreover, the study of the textural perfection of the deposits reveals that the presence of particles leads to the worsening of the quality of the observed 〈220〉 preferred orientation. Composites with high concentration of embedded particles exhibit a preferred crystal orientation of 〈111〉. The more the embedded Fe2O3 particles in the metallic matrix, the smaller the sizes of the crystallite for the composite deposits.

Electrochemical codeposition of PMMA particles with zinc

Zinc matrix composite coatings containing polymethyl methacrylate (PMMA) particles were electrodeposited from an aqueous acidic (pH 2.0 and 4.0), lignosulfonate solution of zinc sulfate on low-carbon steel substrates, under galvanostatic, either constant or pulse current, plating conditions at current densities of 2 and 20 A dm − 2 . The effect of particle inclusion on the deposit electrocrystallization was investigated by X-ray diffraction and scanning electron microscopy. The observed dependence of the PMMA content of the deposits on bath pH and applied current density was illustrated in terms of the particle surface charge variation and their interaction with the growing metal phase. The corrosion resistance of the composite coatings was evaluated by Tafel analysis.

The kinetics of Ni–Co/SiC composite coatings electrodeposition

Ni–Co/SiC composite coatings with various contents of SiC particles were electrodeposited in a modified Watt's type of Ni–Co bath containing suspended 20 nm SiC particles. Deposition parameters including current density, bath SiC concentration and magnetic stirring rate were optimized for the highest amount of the SiC codeposition: the current density of 4 A/dm 2, 40 g/dm 3 SiC concentration and 480 rpm stirring rate. In order to study the SiC particles codeposition, the Guglielmi's model of codeposition was modified for high volume percentages of the second phase and the modified model was employed to explain the effects of deposition parameters on the kinetics of the particles codeposition. Moreover, the influence of suspended SiC particles on the anomalous electrodeposition of Ni 2+ and Co 2+ ions was studied. In the presence of these particulates, anomalous electrodeposition of Ni 2+ and Co 2+ ions was enhanced.

KINETIC STUDY OF WC PARTICLES INCORPORATION IN NICKEL COMPOSITE PLATING

The particles, suspended in the electrolyte, can be co-deposited with metal. The co-deposition behaviors of WC and Co-coated WC particles on nickel matrix were investigated. Many operating parameters that influence on the quantity of incorporated particles, including current density, bath agitation and electrolyte composition were investigated. The co-deposition of particles during electroplating depends on the rate of metal deposition and on the flux of particles to the film surface. The growth rate of the metal film is determined by the current density, whereas the flux of particles to the electrode surface is dependent on the particle size, particle concentration in solution, the electrode rotation rate, the particle diffusion coefficient, and the electrode geometry. The kinetic parameters in the co-deposition were calculated from the experimental results. Co-coated WC particles were easily incorporated in the matrix than WC particles from the calculated and experimental results.

Effect of specimen orientation and heat treatment on electroless Ni-PTFE-MoS2 composite coatings

In this study, the effects of simultaneous co-deposition of polytetrafluoroethylene (PTFE) and MoS2 particles on tribological properties of electroless nickel (EN) coating were studied. The influences of specimen orientation and heat treatment on EN-PTFE-MoS2 composite coatings were also investigated. Scanning electron microscopy was used to study the morphology of coatings and the distributions of the lubricant particles in the deposits. Chemical analyses of coatings were done by electron dispersive spectrometry. The phases of the coatings were identified by X-ray diffraction utilizing CuKα radiation. Wear and friction properties of the coatings were also determined by pin-on-disk wear tester. The wear investigations showed that the EN-PTFE-MoS2 composite coating performs better than EN-PTFE and EN-MoS2 coatings in terms of friction coefficient and wear resistance. PTFE and MoS2 contents of the EN-PTFE-MoS2 coating were increased by changing the specimen orientation from vertical to horizontal configuration, which leads to enhancement in tribological properties of the coating. After heat treatment, the wear rate of EN matrix composite coating decreased with corresponding change in phase structure.