Crystallization and Formation of Compound from Amorphous Phase by B⁺-Ion Implantation in Iron and FeCr Alloy

抄録

Iron and σ-FeCr (Fe₅₀Cr₅₀) alloy were implanted with B⁺-ion at room temperature. For both materials, B⁺-ion implantation could lead to the formation of amorphous phases. The crystallization process of these amorphous phases was studied by high voltage transmission electron microscopy (HVTEM), selected area electron diffraction (SAD) and energy dispersive X-ray analysis (EDX). The distribution of boron atoms was measured by Auger electron spectroscopy (AES). The amorphous Fe–B alloy which was produced by B⁺-ion implantation decomposed into metastable Fe₃B and Fe₂₃B₆ near to the crystallization temperature. Thermally stable Fe₂B was observed at higher temperatures. In the case of crystallization of the amorphous Fe–Cr–B alloy prepared by B⁺-ion implantation, thermally stable (Fe, Cr)₂B and σ-FeCr phase could be observed. However, the existence of metastable phases in Fe–Cr–B alloy, which can be generally observed under decompositions of transition metal-metalloid amorphous alloys, could not be ascertained.