Structural study of Cu2−x_{2-x}Se alloys produced by mechanical alloying

The crystalline structures of superionic high temperature copper selenides Cu$_{2-x}$Se ($0 \le x \le 0.25$) produced by Mechanical Alloying were investigated using X-ray diffraction (XRD) technique. The measured XRD patterns showed the presence of the peaks corresponding to the crystalline superionic high temperature $\alpha$-Cu$_2$Se phase in the as-milled sample, and its structural data were determined by means of a Rietveld refinement procedure. After a heat treatment in argon at 200$^\circ$C for 90 h, this phase transforms to the superionic high temperature $\alpha$-Cu$_{1.8}$Se phase, whose structural data where also determined through the Rietveld refinement. In this phase, a very low occupation of the trigonal 32(f) sites ($\sim 3$%) by Cu ions is found. In order to explain the evolution of the phases in the samples, two possible mechanisms are suggested: the high mobility of Cu ions in superionic phases and the intense diffusive processes in the interfacial component of samples produced by Mechanical Alloying.Comment: 2 figures, submitted to Acta Crystallographic

Aging of a nanostructured Zn50Se50 alloy produced by mechanical alloying

The aging of a nanocrystalline equiatomic ZnSe alloy produced by mechanical alloying was investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques. The measured XRD patterns showed that Se atoms located at interfacial component migrated with aging giving raise to a crystalline selenium (c-Se) phase. DSC spectra of heat-treated samples at temperatures above 221oC followed by quenching showed that the c-Se particles changed to the amorphous state. It was also observed that the as-milled and aged samples are highly hydrophilic. The lattice parameters and the average crystallite sizes were calculated as a function of time of aging and temperature of heat treatment.Comment: Submitted to Solid State Communications, 4 figure

Th-P16:264 impact of a major randomized clinical trial on LDL cholesterol levels in the aggressive reduction of inflammation stops events (ARISE) trial

No abstract available