Processing of barium hexaferrite by high energy milling

摘要

Processing barium hexaferrites ceramic magnetic materials was investigated using high-energy ball milling of iron oxide and barium carbonate powders. Submicrometers particles was obtained by milling using powder ratios of 4:1 and 10:1 after 1 hour and 5 hours milling time, on a Spex mill. Barium hexaferrites of composition BaFe_(12)O_(19) was obtained after heat treatment in temperatures range from 1100 to 1300℃. The results obtained show formation of large agglomerates (around 10 micrometer) of grains with size less than 1 micrometer and low densification after heat treatment of pellets from 1100 to 1300℃. Hysteresis curves show a change in loop form due to grain growth and values of coercivity of 4,2 KOe, remanente magnetization of 40emu/g and magnetization of 70emu/g.