MORPHOLOGY OF MELT-SPUN SILICON ALLOY RIBBONS

Morphological investigations have been performed on melt-spun ribbons of silicon-based binary alloys containing aluminium, copper, cobalt an d vanadium. Additions of strontium and phosphorus were made to the alu minium and copper alloys to find that structure modification effects a t high cooling rates are indicated. The ribbons 50 mum thick and 2-3 m m wide were prepared by induction melting and copper die casting and s ubsequent melt spinning under an inert atmosphere. The primary silicon crystals were identified as typically 5 mum equiaxed dendritic or 20 mum columnar dendritic faceted crystals embedded in eutectic. High sil icon content ribbons exhibit more dendritic silicon crystals than low silicon content ribbons did. All melt-spun ribbons were brittle in the as-produced condition.