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Crystallisation Temperature (crystallisation + temperature)

Distribution by Scientific Domains
Physics and Astronomy75%

Selected Abstracts

Effect of heat treatment on various physical properties in Zr80Ni20 metallic glass

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2006
I. Kokanovi
Abstract The effect of heat treatment on various physical properties in Zr80Ni20 metallic glass has been investigated by means of differential scanning calorimetry and electrical resistivity measurements. Experimental values for the crystallisation temperature and activation energy of the crystallisation processes were derived by studying these processes at different heating rates. The electrical resistivity of the annealed samples up to a temperature slightly above the first crystallization exotherm decreases with decreasing heating rates and increasing annealing temperatures. The temperature dependence of the electrical resistivity of the samples has been interpreted in terms of the weak localization of electrons and contribution by electron,phonon scattering. The contribution by electron,phonon scattering increases with increasing the fraction of crystalline phases in the glass matrix. The superconducting transition temperature, Tc, of the Zr80Ni20 metallic glass annealed at heating rates of 60 K/min and 10 K/min up to annealing temperatures below its second crystallisation exotherm decreases with decreasing heating rates and increasing annealing temperatures. The homogeneity of the annealed Zr80Ni20 metallic glass is discussed by using the superconducting transition width as a criterion. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Thermomagnetic monitoring of nanocomposite formation in mechanically alloyed Nd,Fe,B alloys

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2004
H. W. Kwon
Abstract A mechanical alloying technique was applied to NdxFe94,xB6 (x = 5.5,11.0) alloys for preparing an exchange-coupled nanocomposite. The structural development during the nanocomposite formation was monitored by thermomagnetic means. The mechanically alloyed NdxFe94,xB6 alloys in the as-milled condition consisted of an amorphous Nd,Fe,B phase and ,-Fe nanocrystallites. The crystallisation temperature of the amorphous phase was independent of the milling time. The amorphous phase in the as-milled NdxFe94,xB6 alloys with higher Nd content had a lower crystallisation temperature. The NdxFe94,xB6 (x = 8.5) alloy milled for longer than 30 h consisted of a two-phase structure containing ,-Fe and Nd2Fe14B phases after being isothermally annealed at 600 °C for 20 min. This annealed powder showed a smooth demagnetisation curve, indicating an intergranular exchange coupling between the hard Nd2Fe14B and soft magnetic ,-Fe grains. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Dependence of magnetoimpedance effect on nanocrystalline structure of Fe-based amorphous ribbons

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004
I. Z. Rahman
Abstract This study investigates the magnetoimpedance (MI) behaviour and its dependence on the nanocrystalline structure due to annealing of nominal composition Fe73.5Cu1Nb3Si13.5B9 metallic glass ribbons. Differential Thermal Analyses have shown two distinct stages of primary and secondary crystallisations at ,532 °C and ,703 °C, respectively. XRD, SEM and AFM have shown the evidence of nanocrystallization and surface roughness initiated by changes from glassy to primary crystalline state. Coercivity has decreased near the primary crystallisation temperature and a monotonous increase between the two stages of crystallisation. Beyond the secondary crystallization temperature, the coercivity value remained practically unchanged. Magnetoimpedance ratio (MIR) is found to be sensitive to the annealing temperature. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Effect of oil content and processing conditions on the thermal behaviour and physicochemical stability of oil-in-water emulsions

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2009
Megan Tippetts
Summary The destabilisation mechanism of oil-in-water (o/w) emulsions was studied as a function of oil content (20% and 40% o/w), homogenisation conditions and crystallisation temperatures (10, 5, 0, ,5 and ,10 °C). A mixture of anhydrous milk fat and soya bean oil was used as the lipid phase and whey protein isolate (2 wt%) as emulsifier. Crystallisation and melting behaviours were analysed using differential scanning calorimetry. Physicochemical stability was measured with a vertical scan macroscopic analyser. Emulsions with 20% oil were found to be less stable than those with 40% oil. For 20% o/w emulsions, the crystallisation was delayed and inhibited in emulsions with smaller droplets and promoted in emulsions with larger droplets when compared with 40% o/w emulsions. Depending on the droplet sizes in the emulsion, the formation of lipid crystals (in combination with the emulsifier) either stabilises (small droplets) or destabilises (big droplets) the emulsion. [source]