Preparation of submicron-sized Sm2Fe17N3 fine powder by ultrasonic spray pyrolysis-hydrogen reduction (USP-HR) and subsequent reduction–diffusion process

摘要

A new reduction–diffusion method for preparing submicron-sized Smsub2/subFesub17/subNsub3/sub was developed. First, submicron-sized α -Fe/Smsub2/subOsub3/sub composite precursors with good dispersibility were prepared directly by ultrasonic spray pyrolysis and hydrogen reduction (USP-HR). Then, the precursor was successfully converted into Smsub2/subFesub17/subNsub3/sub powder by Ca reduction–diffusion and nitridation. The results displayed that the precursor prepared by USP-HR was a monodisperse homogeneous composite of spherical particles of α -Fe and Smsub2/subOsub3/sub. α -Fe and Smsub2/subOsub3/sub exist in an intercalated structure in the composite spherical particles. This creates conditions for the preparation of ultrafine Smsub2/subFesub17/subNsub3/sub particles with uniform sizes and dispersity. The results show that Smsub2/subFesub17/subNsub3/sub is a single-phase, composed of submicron-sized particles with no other impurity phases. The physical property measurement system shows that the coercivity of 0.616 ± 0.347 μ m particles reaches 14.7 kOe.