Codeposition Of SiC Particles Research Articles

The Effects of Additives, Particles Load and Current Density on Codeposition of SiC Particles in NiP Nanocomposite Coatings

In this study, electrodeposition of NiP composite coatings with the addition of SiC 100 nm was carried out on low carbon steel studying the effect of additives (sodium dodecyl sulfate, saccharin), particles load (10 or 20 g/L) and current density (1, 2 and 4 A/dm2). As a benchmark, coatings from an additive-free bath were also deposited, despite additives being essential for a good quality of the coatings. The coating’s morphology and composition were evaluated by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). It was shown that by addition of sodium dodecyl sulfate (SDS), pure NiP coating with a higher P content was achieved, and their morphology changed to nodular. SDS also reduced the codeposited fraction of SiC particles, while saccharin increased it. SiC loading and current density had less impact respect to the additives on codeposition of SiC particles. Finally, the microhardness of NiP coatings did not increase linearly by codeposition of SiC particles.

Properties of electrodeposited invar Fe–Ni alloy/SiC composite film

Electrodeposited Invar Fe–Ni alloy/SiC composite films were obtained by the composite electroplating method, and the properties of the composite films were assessed correlated to their microstructure. Invar Fe–35 to 37mass% Ni alloy/SiC composite films with the maximum SiC contents of 20.8vol% were obtained. The co-deposition of SiC particles into the Invar Fe–35 to 37mass% Ni alloy film increased the hardness of the as-deposited films, and suppressed the decrease in hardness by the heat treatment at 600°C; the heat treatment is essential to reduce the coefficient of thermal expansion of the electrodeposited Invar films. The hardness of the composite films with around 20vol% of SiC remained almost unchanged after 600°C heat treatment. This was attributed to the inhibition of grain growth by SiC particle distribution. The electrodeposited Invar Fe–35 to 37mass% Ni alloy/SiC (approximately 20vol%) composite films after the heat treatment at 600°C both exhibited sufficiently high hardness and low CTE, and therefore, these composite films can be used in the fabrication of MEMS elements where high mechanical strength and high thermal dimensional stability are required.

Electrodeposition of Invar Fe-Ni Alloy/SiC Particle Composite

We fabricated electrodeposited Invar Fe–Ni alloy/SiC composites and assessed their hardness properties. Using the composite plating method with SiC particles of 0.5 µm diameter, we achieved Invar Fe–Ni alloy/SiC composites with SiC at concentrations as high as 22.4 vol%. The co-deposition of SiC particles into the Invar Fe–Ni alloy suppressed the decrease in hardness of the composites after annealing at 600°C for reducing its CTE, and the hardness of the composites was greater than that of the electrodeposited Invar alloys with annealing and pyrometallurgically produced Invar alloys. Consequently, the 600°C annealing of the electrodeposited Invar Fe–Ni alloy/SiC composites with SiC (20 vol% or more) afforded Invar/SiC composites with a high degree of hardness of approximately 200 HV and a low CTE of approximately 1–2 ppm/°C. These composite films can be used in the fabrication of MEMS elements that require high mechanical strength and high thermal dimensional stability.

A reciprocating wear study on the effect of surfactant concentration and sliding speed in the electro codeposited Ni/SiCp metal matrix composites

In this present work, Ni/SiC metal matrix composite coatings were prepared from a modified Watt’s type electrolyte containing nano-SiC suspended particles by direct current plating method to increase the wear resistance of Ni. The influence of surfactant content on codeposition of SiC particles within the matrix and tribological properties were investigated. A wide particle size range (between 0.1 and 1.0 µm) was chosen to provide a high load bearing ability for the codeposited layers. The wear tests were carried out at different sliding speeds by using a constant load. The influence of sliding speed on the tribological performances of the coatings has been investigated by using a reciprocating ball-on disk apparatus. Wear resistances and friction coefficients of Ni/SiC composites were decreased by increasing sliding speed due to temperature-controlled surface oxidation. The change in wear mechanisms by changing surfactant content and sliding speeds were also comprehensively studied.

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.

Codeposition of SiC Particles with Electrolytic Nickel

Codeposition of SiC Particles with Electrolytic Nickel

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 cobalt in the presence of Cs + ions

Electrodeposition of SiC particles with cobalt matrix in the presence of cesium ions was studied. The influence of Cs + concentration (0–37.6 mM) on the cathodic polarization curves was determined in galvanostatic and potentiodynamic measurements. It was found that the presence of Cs + in the solution enhanced adsorption of Co 2+ ions on SiC, but preferential cesium adsorption occurred simultaneously. The last phenomena resulted in cesium incorporation in the composite coating. Surface charge of SiC powder and amounts of functional groups on SiC surface were determined. The particles incorporation into deposits was only little dependent on cesium concentration in the bath. Structure of the composite coatings was studied by microscopic observations. Microhardness of the deposits was also determined.