A General Method for Quantifying the Amorphous Phase in Nano Polycrystalline Materials

Abstract

The grain boundary area has a great influence on the polycrystalline material properties and in nano crystallized metals. It could be considered as a glass metal phase in addition to crystallites in a composite structure. In this research, a general procedure for directly quantifying the crystalline and amorphous phases is introduced by using an x-ray diffractometry technique.Nickel with a nano crystalline structure was deposited onto pure copper samples with grain sizes of between 17 to 124 nm by an electroplating technique. A combination of measuring the area of the XRD pattern characteristic peaks and x-ray background scattering were used for the estimation of the crystalline and amorphous volume percentages. The results show that there is a non-linear relationship between the percentage of the crystalline phase calculated by the geometrical method and the area of the selected XRD peak. An experimental formula is suggested for the calculation of the crystalline phase volume percentage of the nano structure nickel samples based on the (200) x-ray peak area.

Preparation and structural characterization of ZnO and CeO 2 nanocomposite powders as ‘active catalytic supports’

“…However, in a large number of our composites both phases exhibited very small grain sizes, for what it is to be expected that a large proportion of their volume (that is, the surfaces of these high surface/volume ratio particles) certainly show amorphous behavior [40].…”

“…The thickness of the disordered surface region around each crystalline domain comprises a few cell parameters. Masoudi et al [40] fixed an arbitrary value of 2 nm for their calculations but, nonetheless, the correct thickness of the surface-affected region remains unknown and can be different for both phases. They depend on the relative stability of the crystalline vs. the amorphous portions of two different oxides.…”

Two-Step Synthesis of VO2 (M) with Tuned Crystallinity

“…To determine the nature and the proportion of the various components present in the three kinds of VO 2 powders, powder X-ray diffraction was used (Figure ). The quantification analysis, using Rietveld refinement with the Fullprof program, was deduced from the scale factor of the different phases either amorphous or crystalline …”