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Abstract: It was found that the dendritic microstructure of an as-cast alloy was changed to an almost equiaxed alloy after 480min of annealing at 700°C. The electrical conductivity of as-cast and hot rolled samples increased from 27.36 and 30.51% IACS to 30.67 and 32.1% IACS after 480min of annealing at 700°C. The dendritic microstructure and the electrical conductivity values of an as-cast alloy annealed for 60min remained almost unchanged when the annealing temperature was increased to 800°C. The hardness values of the samples that were hot rolled and annealed for 60min were higher than those of the as-cast samples for all annealing temperatures. The electrical conductivity values of the hot rolled and as-cast samples were almost the same after annealing at 800°C for 60min. It was shown that after 20% cold work, the electrical conductivity value of the as-cast sample decreased from 30.5% IACS to 22.6% IACS. The electrical conductivity values of the samples were not significantly changed when the cold work was increased from 20% to 60%. The electrical conductivity values of the 20%, 40% and 60% cold worked samples increased from 22.62, 24.69 and 26.63 to 27.14,28.36 and 30.55% IACS, respectively, after 30min annealing at 400°C. [Copyright &y& Elsevier]

Nanocrystalline strontium hexaferrite powder has been prepared by a new mechanochemical method in which the single phase hexaferrite was obtained via a sol-gel autocombustion process followed by an intermediate high energy milling step and subsequent annealing. The effects of the intermediate milling on the phase evolution, crystallite size and annealing behavior of the final products were investigated using the X-ray diffraction (XRD) technique. The single phase strontium hexaferrite was obtained at an annealing temperature of 800°C, while this temperature was 1,000°C for the powder synthesized without milling. It could be seen that an intermediate milling accelerates the formation of strontium hexaferrite during the calcination process. The results showed that in the milled powder, the average crystallite size of the ferrite was about 40 nm and much smaller than that of the nonmilled powder. Magnetic properties were also measured by a vibrating sample magnetometer (VSM). The particle morphology was then studied by scanning and transmission electron microscopes (SEM and TEM). [ABSTRACT FROM AUTHOR]

Abstract: In this research, the effects of chlorine gas at different chlorine partial pressures and carbon concentrations on the carbochlorination of zirconia were studied. It was found that in briquettes containing 18.7%wt carbon, in a chlorine partial pressure range of 0.25–0.75atm and for a reacted fraction of less than 0.7, the chemical reaction model was dominant for the carbochlorination process of zirconia. The order of reaction into chlorine gas (n) in this situation was 0.57. Moreover, the best weight ratio of carbon to zirconia was 40/60. In this case, the activation energy of the reaction was 209.9kJmol−1 in a temperature range of 1023–1223K, and the dominant model was the chemical reaction model. [ABSTRACT FROM AUTHOR]