Guan-Kun Liu

Electrodeposition of Lu-Co-Bi Thin Films in an Organic Bath

The electrodeposition of Lu-Co-Bi thin films from Lu(III), Co(II), and Bi(III) solutions was studied in nonaqueous dimethysulfoxide (DMSO). Different substrates have been used (platinum and copper), and the effect of them on the electrochemical behavior of the studied ions is shown. The obtained Lu-Co-Bi thin films were subjected to scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction (XRD) analysis. The lutetium content in Lu-Co-Bi thin film increases as the potential was made more cathodic, reaching a maximum value of 26.84 wt %, and then decreases. The films were amorphous. After heat-treatment of crystallization at 520°C for 1 h, the alloy phase of Co 2 Lu and Bi 1.5 Lu 0.5 O 3 can be found in the XRD patterns.

Electrodeposition of Tm-Co Alloy Films in Dimethylsulfoxide

The conductivity of three thulium (Tm) salts has been studied in dimethylsulfoxide (DMSO) at 298 K. Tm(NO 3 ) 3 has strong electrolyte properties in DMSO. Cyclic voltammetry has been used to investigate the electrochemical behavior of the Tm 3+ ion in 0.01 mol L -1 Tm(NO 3 ) 3 -0.1 mol L -1 LiClO 4 -DMSO system on the Pt electrode at 299 K. The experimental results of cyclic voltammetry indicate that the reduction of the Tm 3+ ion is an irreversible process. The transfer coefficient and the diffusion coefficient of Tm 3+ ion have been measured. In a nonaqueous system, the surface of Tm-Co alloy films prepared by the potentiostatic deposition technique is uniform, adhesive, compact, and showed a metallic luster. Tm-Co alloy films are amorphous, as proven by X-ray diffraction spectrometry. Tm-Co alloy films have soft magnetic property at 293 K. This kind of rare earth film prepared from organic solvent could have the potential application as a magnetic material.

Studies on the Electrodeposition of Ce–Co Rare Earth Alloy Thin Films in Urea-DMSO systems

Cyclic voltammetry was used to investigate the electrochemical behaviors of Ce(III) and Co(II) in 3.00 mol L -1 urea dimethyl sulfoxide (DMSO), and the electrode processes of Ce(III) and Co(II) reducing on Pt electrodes in 3.00 mol L -1 urea-DMSO system were irreversible steps. The transfer coefficient and diffusion coefficient of Ce(III) in the 0.01 mol L -1 Ce(CH 3 SO 3 ) 3 -3.00 mol L -1 urea-DMSO system were calculated as 0.055 and 1.77 X 10 -10 m 2 s -1 at 298.15 K, respectively. The transfer coefficient and diffusion coefficient of Co(II) in 0.01 mol L -1 CoCl 2 -3.00 mol L -1 urea-DMSO system were calculated as 0.05 and 3.16 X 10 -10 m 2 s -1 at 298.15 K, respectively. The Ce-Co alloy thin films, which were smooth, uniform, and should metallic luster, were obtained by potentiostatic electrodepositon and cyclic electrodeposition in 0.01 mol L -1 Ce(CH 3 SO 3 ) 3 -0.01 mol L -1 CoCl 2 -3.00 mol L -1 urea-DMSO system. The prepared Ce-Co alloy thin films were amorphous, as proved by X-ray diffraction analysis. After heat-treatment of crystallization at 1173.15 K for 1 h, the alloy phase of Ce 5 Co 19 , CeCo 5 , and CeCo 2 could be found in the XRD patterns. The prepared Ce-Co alloy thin films showed soft magnetic properties at 5 and 293 K, respectively.

Electrochemical Preparation of Nanograin Sized Dy-Co-Bi Alloy Thin Films by Cyclic Electrodeposition and Their Magnetism

The electrochemical preparation of the nanograin sized Dy-Co-Bi ternary rare earth alloy thin films were investigated by cyclic electrodeposition at room temperature. The electrodeposition was carried out by cyclic electrolysis between two potentials with voltage scan rates in the range from 0.01 to 0.10 V s -1 . Experimental results indicated that the optimum cyclic potentials were the upper potential within a range from -0.80 to -1.20 V and the lower potential within a range from -2.30 to -2.60 V, and only low DyCl 3 concentrations were suitable to prepare homogeneous, crack-free, and nano-sized Dy-Co-Bi thin films. The potentiostatic and galvanostatic stripping techniques were used for electrochemical characterization of the prepared Dy-Co-Bi thin films. The prepared thin films were amorphous characterized by X-ray diffraction. The magnetic measurements of the nanograin sized Dy -Co-Bi thin films showed that they had a spin-glass-like behavior and an unusual characteristic time at 100 K.

Electrochemical Preparation and Characterization of Nanostructured Ag-Bi Thin Films in Organic Baths

We report on the preparation of nanostructured Ag-Bi alloy thin films by galvanostatic electrodeposition in organic baths, which also provides a very good way to prepare the nanostructured active metal alloy thin films. Control of the current densities and relative concentrations of the cations allowed the diameters of Ag-Bi nanocrystallites to be specified in the range of 20-50 nm. The surface morphologies of the films electrodeposited in an organic dimethysulfoxide bath containing 0.01 mol/L Bi(NO 3 ) 3 -0.01 mol/L AgClO 4 -0.1 mol/L LiClO 4 with a current density of 1.0 mA/cm 2 were uniform in metallic luster, and the films were adhesive. The results of X-ray diffraction measurements indicated that the nanostructured Ag-Bi thin films were the mixture of silver-rich solid solution phase and pure bismuth phase. The optical absorptance spectra of the nanostructured Ag-Bi thin films were broader, and increased in magnitude and shifted toward lower energies for increasing Ag content in the Ag-Bi thin films. The resistivities of the films decreased with the thickness increasing.