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

Abstract

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/dm 2 ). 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.Meanwhile, the amount and distribution of particles are related to electrodeposition parameters including particle characteristics (particle shape, size, concentration and surface charge), electrolyte composition (additives, surfactant type and concentration), pH and applied current (direct or pulsed current and current density) [17][18][19][20][21]. Several studies have reported the effect of process parameters on the amount of codeposited particles in the metal matrix [18][19][20][21][22][23][24][25]. However, a low number of particles are usually codeposited in the case of nanoparticles, and they tend to agglomerate, which results in the poor mechanical behaviour of the coatings. Hence, increasing the amount of codeposition as well as improving the particle distribution in the matrix are the crucial issues that require further investigation.It is well known that introducing additives to the electrolyte affects the properties and appearance of deposits [20,22,25]. Additives can be categorised based on their application as grain refiners, levelling agents, and wetting agents or surfactants. Saccharin is a common brightening agent in the electrodeposition of nickel, which refines grains, inhibits the hydrogen evolution reaction and reduces the internal stress of the coatings [25][26][27][28]. In previous studies, it was shown that the addition of saccharin significantly improves the cathode current efficiency of the NiP electrodeposition [29]. However, saccharin decreased the SiC codeposition and phosphorus content, compared to deposits obtained from saccharin-free baths [30].Surfactants such as sodium dodecyl sulfate (SDS) are needed in the case of electrodeposition processes where the current efficiency is below 100%. Hydrogen evolution is the common secondary cathodic reaction, and SDS can reduce the residence time of the H 2 bubble on the cathodic surface, and also pitting as well as porosity. Surfactants are beneficial for enhancing the stability and uniformity of the electrolyte by increasing the wettability an...

Ultrasound Supported Galvanostatic Deposition of Zn Coatings Reinforced with Nano-, Submicro-, and Micro-SiC Particles—Weak Acidic Chloride Baths

“…The same effect was reported for the electrodeposition of a Ni-based coating reinforced with a SiC particles, and was explained by the ability of the particles to adsorb protons, which in turn may result in the enhancement of HER. [ 34 , 35 ]…”

“…The same effect was reported for the electrodeposition of a Ni-based coating reinforced with a SiC particles, and was explained by the ability of the particles to adsorb protons, which in turn may result in the enhancement of HER. [34,35] The presence of ultrasound caused the opposite effect, which manifested with a slight decrease in the Zn deposition efficiency with increasing current density. In the case of the electrolysis carried out under ultrasonic agitation, we observed a decrease in efficiency by approx.…”

Study of the effect of pulse plating parameters on the electrodeposition of NiP and NiP/SiC coatings and their microhardness values

“…I is the applied current (A), t is the deposition duration (s), and F is the Faraday's constant (96,485 coulombs). 37,38 Selected samples were annealed at 400°C with a heating rate of 10°C min −1 for 1 h in air to study the effect of heat treatment on their microhardness.…”

Influence of Element Penetration Region on Adhesion and Corrosion Performance of Ni-Base Coatings

“…The corrosion potential of the Ni-P-SiC coating prepared with the sandblasting pretreatment was the highest, reaching −0.30 V, and the corrosion current density was the lowest, reaching 8.45 × 10 −7 A•cm −2 . The reason is that when the SiC nanoparticles were uniformly distributed on the Ni-P-SiC coating, the coating structure was refined, and the effective area of its infiltration in the corrosion solution was reduced [30]. The addition of SiC nanoparticles in the Ni-P coating further expanded the element penetration region, increased the coating adhesion, and improved the corrosion resistance of the coating.…”