EXAFS STUDY OF METAL-COATED PARTICLES PRODUCED BY BALL-MILLING

EXAFS measurements have been carried out on mixtures of Sn with Ge and Si, and Pt with SiO2 which have been ball milled for extended periods . In these systems the brittle component (Ge, Si, or SiO2) is ground t o nanocrystalline dimensions while the ductile metal is found to coat the outer surface of the particles. Analysis shows that in the Sn-Ge a nd Sn-Si systems, mixing at the interface is found to form apparently cubic SnGe and SnSi alloys respectively. In the Pt-SiO2 system while n o mixing is observed, the Pt is found to be highly dispersed on the su rface of SiO2 particles.