Study of BiSb-SiO2 nanocomposite powders produced by an arc plasma processing

Nanocomposite powders composed of BiSb alloys and SiO2 nanoparticles were prepared by direct co-evaporation of a bismuth antimony pre-alloyed ingot and a silica disk by an are flame, in a pure Ar atmosphere. Microstructural examinations of the raw materials after powder production, associated to EDS and EELS analyses allowed to propose an atomisation mechanism. The are parameters influence on the powders composition was studied. The microstructure of the powders was examined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. EDS and EELS analyses allowed to identify and locate the silicon oxide nano-grains. They are dispersed in the core and on the surface of bismuth-antimony grains. (C) 1999 Acta Metallurgica Inc.