Showing papers on "Amorphism published in 2004"
TL;DR: In this article, the effects of solution composition and deposition conditions on deposit composition, coercivity, and morphology were investigated using dc and pulse current electrodeposition, resulting in nanocrystalline deposits approaching amorphism.
Abstract: Binary iron group (IG)-rare earth (RE) and ternary IG-RE-B alloys were codeposited from aqueous chloride and sulfamate solutions containing glycine as the complexing agent. The effects of solution composition and deposition conditions on deposit composition, coercivity, and morphology were investigated using dc and pulse current electrodeposition, resulting in nanocrystalline deposits approaching amorphism (grain size, ∼5 nm). Continuing research indicates substantially increased RE deposit contents have been achieved with modifications in solution composition and ratios of IG and RE to glycine with applied current density ≥ 300 mA cm -2 and vigorous agitation; e.g., CoSm deposits containing 15-18 atom % Sm have been obtained. A mechanism for the codeposition of the alloys is proposed. It involves hetero-nuclear glycinato coordination complexes as a result of the zwitterionic characteristics of glycine. The complexes adsorbed on the cathode provide step-wise reduction of the depositing metals with surface adsorbed H atoms and/or direct electron transfer, resulting in alloy deposits.
57 citations
TL;DR: In this paper, Zn-Ni-P and Zn−Fe-P alloys were electrodeposited on carbon steel plates and their morphology, composition and structure were evaluated as a function of electrolyte composition and pH.
51 citations
TL;DR: In this article, the dynamics of amorphization induced in phase-change optical recording media by focused laser pulses of subnanosecond duration was investigated by using real-time reflectivity measurements with a pump-and-probe technique.
Abstract: We have investigated the dynamics of amorphization induced in phase-change optical recording media by focused laser pulses of subnanosecond duration. We initiated localized amorphism by using a focused laser beam to melt the phase-change material and completed the change by rapid cooling by means of thermal diffusion. These studies were conducted by use of real-time reflectivity measurements with a pump-and-probe technique in which both pump and probe pulses had a duration of ∼510 ps. Our transient-reflectivity measurements indicate that the process that leads to amorphism has three distinct stages, namely, rapid melting, solidification, and slow relaxation.
19 citations
TL;DR: In this article, the surface of AB5 alloy was modified by shorter carbon nanotubes and thin carbon flake, respectively, and the electrochemical properties of the obtained materials were measured and compared with those of the original AB5 Alloy.
18 citations
TL;DR: The structure of fraction isolated by thermal sublimation of ultradisperse polytetrafluoroethylene (UPTFE) powder has been studied by IR spectroscopy.
Abstract: The structure of fractions isolated by thermal sublimation of ultradisperse polytetrafluoroethylene (UPTFE) powder has been studied by IR spectroscopy. At 50°C–160°C, fractions of highly amorphous fragments are condensed on a cold receiver; the fragments are constructed from branched chains with terminal olefin groups. Fractions isolated at 300°C and higher are close in structure to PTFE and are highly crystalline. It is assumed that sample amorphism is due to the irregular distribution of the fractions of fragments with terminal olefin and lateral fluoromethyl groups in the structures.
12 citations
Journal Article•
TL;DR: In this article, the steady-state crystallization of calcium phosphates and carbonates from aqueous solutions simulating human blood plasma under typical physiological conditions (37.0 ′ 0.2°C and pH 7.35 Ã 0.05) was performed.
Abstract: Experiments on the steady-state crystallization of calcium phosphates and carbonates from aqueous solutions simulating human blood plasma under typical physiological conditions (37.0 ′ 0.2°C and pH 7.35 ′ 0.05) were performed. The influence of a dissolved protein (bovine serum albumin) on the crystallization was studied. It was found that the amorphism of the precipitate increases with the concentration of the dissolved protein due to the co-crystallization of the organic and inorganic phases. It was shown that results of this study simulate the formation of bone tissues in mammals.
4 citations
Patent•
22 Dec 2004
1 citations
1 Jan 2004
TL;DR: In this paper, the cooling rate of a 50 μm thick magnesium ribbon on the free surface of a melt spinning copper roller was estimated using a one-dimensional heat conduction equation.
Abstract: Critical cooling rate is a key parameter characterizing the formation ability of amorphism of (amorphous) alloys, but it is still difficult to measure and estimate it correctly. However, based on the heat transfer theory and liquid solidification theory, the heat transfer during the rapid solidification process of a ribbon prepared by melt spinning can be approximately modeled by one-dimensional heat conduction equation, so that the temperature distribution in the ribbon and the cooling rate of the ribbon can be determined by the integration of this equation. According to the integration function, when the molten liquid of a 50 μm thick magnesium ribbon on the free surface of melt spinning copper roller solidifies out, the calculated cooling rate of the ribbon is up to 5.84×10~6 K/s. This result is coincident very well with other estimation values reported before.
1 citations