The surface structure and catalytic properties of partially crystallized Fe---Si---B alloys

The surface structure of partially crystallized Fe₇₈Si₁₂B₁₀ alloys was investigated by means of X-ray diffraction, high resolution electron microscopy and Auger electron spectroscopy and was correlated with their catalytic properties. Highly dispersed minute -Fe particles were observed in the amorphous matrix. After chemical treatment of the partially crystallized Fe---Si---B alloys with NaOH solution, large stripes of B₂O₃ were discovered because of the aggregation of a boron-containing phase. Boron- or silicon-containing surface films were formed on the -Fe particles by diffusion, causing the deactivation of these alloy catalysts.