Phase transformations in Si-based alloy powder mixtures induced by microwave heating in a 2.45 GHz single-mode applicator

Microwave radiation was used to heat Si and Fe blend powders as well as Si-based alloy powders in a single-mode microwave applicator. The heating behavior and phase transformation of these powders in a separated electric (E)- and magnetic (H)-field were investigated. The increase of Fe content in the mixture of Si and Fe powder enhanced its microwave absorption capability in both the E- and H-fields. Si₉₀Zr₁₀ and Si₉₅Y ₅ alloy powders could be heated up more easily in the H-field than E-field. Microwave heating of Si and Fe blend powders induced the formation of FeSi₂ and FeSi phases in the E- and H-field under a flowing nitrogen gas. When Si₇₀Fe₃₀ blend powders were heated by microwaves in air, crystalline Fe₃O₄ phase could be detected. SiY phase was formed by microwave heating of Si₉₅Y₅ alloy powder in the H-field.