Electrodeposition nanocrystalline

F. Ebrahimi, Z. Ahmed, The effect of current density on properties of electrodeposited nanocrystalline nickel , J. Appl. Electrochem., 33 (8), (2003), 733-739. 

Y. Giga, Y. Kimoto, Demonstration of an inverse Hall-Petch relationship in electrodeposited nanocrystalline Ni-W alloys through tensile testing. Scripta Mater. 55(2), 143-146 (2006)... 

Erb U., Aust K. T. and Palumbo G. (2002), Electrodeposited nanocrystalline materials , in Koch C. C. (Ed.), Nanostructured materials processing, properties and potential applications. Norwich, NY William Andrew Pubhshing, p. 179. 

Effect of electrodeposited nanocrystalline Ni-Co alloy coatings on the corrosion wear ofAlSI 1045 carbon steel... 

Surface morphology of the wear track of electrodeposited nanocrystalline Ni-Co alloy coatings after subjecting them to tribocorrosion tests at their respective OCRs under the same test conditions as Fig. 8.15 (a), (b) no additive (c) saccharin (1 g/l) and (d) sodium lauryl sulfate (0.25 g/l) (a) prepared at 40 mA/cm ... 

Palladium and gold Palladium electrodeposition is of special interest for catalysis and for nanotechnology. It has been reported [49] that it can be deposited from basic chloroaluminate liquids, while in the acidic regime the low solubility of PdCl2 and passivation phenomena complicate the deposition. In our experience, however, thick Pd layers are difficult to obtain from basic chloroaluminates. With different melt compositions and special electrochemical techniques at temperatures up to 100 °C we succeeded in depositing mirror-bright and thick nanocrystalline palladium coatings [10]. 

Mastai Y, Hodes G (1997) Size quantization in electrodeposited CdTe nanocrystalline films. 

The electrodeposition of metals from ionic liquids is a novel method for the production of nanocrystalline metals and alloys, because the grain size can be adjusted by varying the electrochemical parameters such as over-potential, current density, pulse parameters, bath composition and temperature and the liquids themselves. Recently, for the first time, nanocrystalline electrodeposition of Al, Fe and Al-Mn alloy has been demonstrated. 

The electrodeposition of chromium in a mixture of choline chloride and chromium(III) chloride hexahydrate has been reported recently [39]. A dark green, viscous liquid is obtained by mixing choline chloride with chromium(III) chloride hexahydrate and the physical properties of this deep eutectic solvent are characteristic of an ionic liquid. The eutectic composition is found to be 1 2 choline chloride/chromium chloride. From this ionic liquid chromium can be electrode-posited efficiently to yield a crack-free deposit [39]. Addition of LiCl to the choline chloride-CrCl3-6H20 liquid was found to allow the deposition of nanocrystalline black chromium films [40], The use of this ionic liquid might offer an environmentally friendly process for electrodeposition of chromium instead of the current chromic acid-based baths. However, some efforts are still necessary to get shining... 

Nanocrystalline copper with an average crystallite size of about 50nm can be obtained without additives in the ionic liquid 1-butyl-l-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP]Tf2N) [92], Because of the limited solubility of the tested copper compounds in this ionic liquid, copper cations were introduced into the ionic liquid by anodic dissolution of a sacrificial copper electrode. The electrodeposition of copper was also investigated in the ionic liquid... 

Nanocrystalline materials have received extensive attention since they show unique mechanical, electronic and chemical properties. As the particle size approaches the nanoscale, the number of atoms in the grain boundaries increases, leading to dramatic effects on the physical properties and on the catalytic activity of the bulk material. Nowadays, there is a wide variety of methods for the preparation of nanocrystalline metals such as thermal spraying, sputter deposition, vapor deposition and electrodeposition. The electrodeposition process is commercially attractive since it can be performed at room temperature and the experimental set-up is less demanding. Furthermore, the particle size can be adjusted over a wide range by controlling the experimental parameters such as overvoltage, current density, composition, and temperature (see Chapter 8). 

Zein El Abedin, S., Moustafa, E., Natter, H., Hempelmann, R., and Endres, F. (2005) Additive free electrodeposition of nanocrystalline aluminium in a water and air stable ionic liquid. Electrochem. Commun., 7,1116. 

In this protocol we describe the electrodeposition of nanocrystalline aluminum without additives in the water- and air-stable ionic liquid 1-butyl T methylpyrrolidinium bis(trifluoromethylsulfonyl) amide [Pyi JTFSA containing... 

Nanocrystalline aluminum can be made in the employed ionic liquid without additives, see Chapter 8. The SEM micrograph of Figure 12.9 shows the surface morphology of a deposited aluminum layer obtained potentiostatically on mild steel at —0.75 V (vs. Al) for 2 h in the upper phase ofthe biphasic mixture [Pyi TfiN M AICI3 at 100 °C. Prior to Al electrodeposition, the electrode was anodically polarized at a potential of 1V (vs. Al) for 2 min. The deposited layer is dense, shining and adherent to the substrate with crystallites in the nanosize regime. 

Figure 12.11 shows the XRD patterns of a nanocrystalline Al film obtained at a constant potential of —1.7V for 2h at 100°C in the ionic liquid [Pyip] TFSA containing 1.6 M AICI3 on a glassy carbon substrate. The XRD patterns show the characteristic diffraction patterns of crystalline Al, furthermore the peaks are rather broad, indicating the small crystallite size of the electrodeposited Al. The grain size of Al was determined using Scherrer s equation to be 34 nm. For more information on the electrodeposition of nanocrystalline aluminum in the employed ionic liquid we refer to Refs. [3, 4]. 

Usually there is a lot of effort required to make nanomaterials by electrochemical means. In aqueous solutions the electrodeposition of nanocrystalline metals requires pulsed electrodeposition and the addition of additives whose reaction mechanism hitherto has only been partly understood (see Chapter 8). A further shortcoming is that usually a compact bulk material is obtained instead of isolated particles. The chemical synthesis of metal or metal oxide nanoparticles in aqueous or organic solutions by colloidal chemistry, for example, also requires additives and often the desired product is only obtained under quite limited chemical conditions. Changing one parameter can lead to a different product. 

---