Enhanced Hardness and Corrosion Resistance of Zn/SiO₂Films by Electrodeposition

Abstract

The electrodeposition of Zn-SiO 2 nanocomposites has been investigated with different electrolytes: triethanolamine as a dispersing agent, and cetyl trimethylammonium bromide and dodecyl dimethylamine oxide as ionic (cationic) and non-ionic surfactants. Appropriate electrophoretic potentials for each solution were obtained using cyclic voltammetry. The results show that the most stable SiO 2 nanoparticles with zeta potential range of 25 to 41 mV, alongwith highest SiO 2 mobility of 0.4 to 0.7 m 2 /V.s were dispersed by triethanolamine in ethanol and the resulting coating adhesion improved up to 5.87 MPa in the standard pull off test, with the enhanced hardness of up to 800 HV. The coating thickness has been seen to increase with increasing potential. The coating morphology investigations reveal three different morphologies for different electrolytes: instantaneous coaxial grain growth for water, hexagonal grain growth for methanol and amorphous structure for ethanol. Corrosion properties of the zinc nanocomposite coatings are discussed where samples with low SiO 2 (<10 wt.%) concentrations are shown to possess higher corrosion resistance than high SiO 2 (>10 wt.%) concentrations.In the last 20 years the interest in electrophoretic deposition (EPD) as a technique to produce advanced materials has widely increased, both in academia and in the industrial sector, and since then a wide range of new applications of EPD for processing a variety of bulk materials and coatings has been reported.

Effects of organically modified nanoclay on cellular morphology, tensile properties, and dimensional stability of flexible polyurethane foams

“…The polarization and EIS measurements show that the composite prepared in the presence of ALES had better corrosion resistance than other composites. Although the exact role of the inert particles in the corrosion reaction has not been well understood, the enhanced corrosion resistance of the composites containing uniform particles has been attributed to various reasons in the literature [6,21,27,37,43]. In this case, this can be attributed to smaller size and more uniform distribution of the silica particles in the composite.…”

“…The importance of nickel-based particle-reinforced composite coatings in engineering applications has been significantly enhanced gradually, and these are currently applied in various technological fields requesting for corrosion, hardness, wear, friction and thermal resistances [5,7,11]. One beneficial particle used in such coating is SiO 2 that according to some studies has an enhancing effect on the corrosion and mechanical resistance of composites [21,22]. SiO 2 particles can act as a barrier film, inhibiting the corrosion of the composite and reducing the consumption rate of the metallic portion of the composites.…”

“…SiO 2 particles can act as a barrier film, inhibiting the corrosion of the composite and reducing the consumption rate of the metallic portion of the composites. It should be mentioned that SiO 2 particles have hydrophilic surfaces and naturally carrying negative charges due to the deprotonation of silanol groups in aqueous solutions (Scheme 1) [12,13,21].…”

Microstructure and corrosion behavior of electrodeposited Zn‐TiN composite coatings

“…At present, the second‐phase particles that are used to prepare the zinc‐based composite coatings are mainly metal or non‐metal oxides which are easily incorporated into the matrix. These reported oxides include SiO 2, CuO, V 2 O 5, ZnO, Al 2 O 3, ZrO 2, TiO 2, CeO 2 , SnO 2 , etc. The corrosion current densities for zinc coatings incorporated by these oxide particles were shown to be obviously lower than that of pure zinc coating and were in the range of half to one third of the intrinsic corrosion current density of pure zinc coating.…”

Communication—Co-Electrodeposition of Ni/SiO2(CH2)3SH Composite: Modified Guglielmi's Model and Mechanism of Nucleation

“…5 But silica is an attractive particle for co-deposition with metals to produce nanocomposite because of its superior physical and chemical properties. 6 It seems that the hydrophilic surface and negative charge of silica are important barriers against silica incorporation during electrodeposition. 5 Several models were proposed for co-electrodeposition of particles.…”