Direct current electrodeposition

The Russell group has applied the template synthesis approach to nanoporous films generated from UV-treated PS-fo-PMMA copolymers [43, 147,233,235,241], which were pre-aligned perpendicular to the substrate by an electric field. Through direct current electrodeposition, they fabricated high-density vertical arrays of ferromagnetic cobalt nanowires (Fig. 10a) [43]. Through subsequent work, they also demonstrated the successful replication... 

There are three types of electrolytic metal deposition processes direct current electrodeposition, pulse plating, and laser-induced metal deposition. ... 

As shown in Eigure 22-6, the apparatus for an analytical electrodeposition without cathode potential control consists of a suitable cell and a 6- to 12-V direct-current... 

In the direct current (DC) electrodeposition, the current source is a DC power source. A power source in the form of a battery or rectifier (which converts alternating current electricity to regulated low-voltage DC current) provides the necessary current. 

Several studies were published in recent years on electrodeposition of W-Co alloys. Donten and Stojek used pulse electrodeposition to increase the tungsten content in amorphous Co-W alloys. These alloys contained, in addition, small amounts of boron or phosphorous. They showed that, if a symmetrical current pulse was used, the tungsten content in the alloys reached a maximum value of 41.4 at.%, which is higher than in the case of direct current deposition. However, when using any asymmetrical... 

High-concentration (40 weight percent [wt%]) ternary Pt alloy samples prepared using the carbothermal technique have yielded surface area and activity values comparable to commercial Pt samples. Platinum/Carbon (Pt/C) prepared by pulse-electrodeposition showed superior surface area and activity when compared to direct current deposited Pt/C electrodes. 

At the University of South Carolina, Pt/C electrodes were fabricated by using direct current (DC) and pulse current electrodeposition methods. With the use of current pulses rather than DC, a higher deposition current density could be used and Pt deposits with a higher surface area were possible. Figure 3 compares the polarization performance of electrodes prepared by pulse electrodeposition (current density=50 mA/cm and duty cycle=0.25) and DC deposition. Electrodes fabricated under pulse deposition conditions display better performance than the DC-plated electrode. The best performance is obtained when the ON time is 100 ms and OFF time is 300 ms. 

Electrodeposition. In this process, a conductive substrate is placed in an electrolyte solution (typically aqueous) that contains a salt of the material of interest. When an electrical potential is apphed between the substrate and a counter electrode, redox chemistry takes place at the surface of the substrate which deposits material. Complex pulse trains and/or high-pulse frequencies are sometimes used to direct current flow and favor desired reactions. A postsynthesis calcination is often performed to reach a desired material phase. Electrodeposition is restricted to deposition of electrically conductive materials and produces polycrystaUine and amorphous films. This process is also appropriate for thin film surface treatment of PEC electrodes, such as electrocatalyst deposition. 

This is of course not the case when working with room temperature ionic liquid systems. Electrochemical and spectroscopic studies of cobalt, copper, and nickel, have been carried out in the AlClj-butylpyridinium chloride molten salt system. The direct current and pulsed current electrodeposition of Ni-Al alloys has also been shown in acidic AlCls-butylpyridinium chloride ionic liquids. This particular alloy has also been shown to be successful in AlCl3-[C2-mim]Cl ashave Co-Al andCu-Al. Electrochemical techniques can also be used to calculate the diffusion coefficients of metal ions. Table 21.2.6 shows the calculated diffusion coefficients and stokes-Einstein products of cobalt(II), copper(I), nickel(II) and zinc(II) in the 40-60 mol% [Cj-mimlCl-AlClj ionic liquid. 

Petrovic BM, Kostic TM (2000) The properties of chromium electrodeposited with programed currents. Part 1 direct current. J Serb Chem Soc 65 55-63... 

Cheh, FLY. and Sard, R. (1971) Electrochemical and structural aspects of gold electrodeposition from dilute solutions by direct current /. Electrochem. Soc., 118 (11), 1737-1747. 

Bonou, L., Eyraud, M., Denoyel, R., and Massiani, Y. (2002) Influence of additives on Cu electrodeposition mechanisms in acid solution direct current study supported by non-electrochemical measurements. Electrochim. Acta, 47 (26), 4139-4148. 

Electrodeposition, also called electrocoating, is a process by which organic materials are coated from aqueous suspension, or solution, onto a conductive substrate under the influence of electricity. The process utilizes direct current for depositing resins, so that predominantly electrophoretic processes operate. Electrophoresis in this context is understood to mean the migration of colloidal or suspended particles in an electric field. The particles migrate, according to their charge, to the anode (anaphoresis) or to the cathode (cataphoresis). 

Electrochemical and structural aspects of gold electrodeposition from dilute solutions by direct current,... 

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