Synthesis and characterization of nanometer-sized Ti-based amorphous powders

We present a simple method for preparing nanometer-sized, Ti-based amorphous powders from the Y₂₈Ti₂₈Al₂₄ Co₂₀ and Y₃₆Ti₂₀Al₂₄ Co₂₀ two-phase amorphous alloys. The initial microstructure of these rapidly quenched alloys is composed of Ti-based, amorphous, spherical, nanometer-sized particles embedded in a Y-based amorphous matrix, with particle size dependent on the alloy composition. The Ti-based powders were extracted from the two-phase amorphous alloys through selective dissolution of the Y-rich matrix in a 0.1 M HNO₃ solution. The powders of size ranging between 20 and 200 nm have smooth and spherical morphology, and exhibit different magnetic behavior than the bulk alloy of identical composition.