Influence of compaction pressure on magnetic characteristics, density, and hardness of barium hexaferrite

Abstract

The effect of varying compacting pressure has been observed in the preparation of permanent magnet barium ferrite. The compaction pressure affects the magnetic characteristic, physical properties, and mechanical properties. The technological process used in this study was a powder metallurgy process. The steps of processes were determination of chemical composition, mixed, calcined, milled, compacted, sintered, and characterization. The raw materials used were waste iron oxide (Fe2O3) and barium carbonate (BaCO3) with a composition ratio of 80:20% weight. Some additives were also added, such as silicon oxide (SiO2), calcium oxide (CaO), and polyvinyl alcohol (PVA). Calcinated temperature at 1200 °C with 3 hour holding time, sintered temperature at 1250 °C with one hour holding time. Compacted pressure varies at a pressure of 1, 2, 3, 4, 5, and 6 tons.cm-2. The magnetic properties were obtained by Magnet Physik Permagraph. The optimum result is at compacting pressure of 6 tons.cm-2, with a value of remanen induction (Br) = 2.03 KG, coercivity (Hc) = 2.156 Koe, maximum field strength (BHmax) = 0.74 MGOe, and density = 4.530 g.cm-3. Hardness test result were obtained using Rockweel-C method of the sample with pressure of 6 tons.cm-2 was 42.5 HRc, but samples with pressure 1, 2, 3, 4, and 5 tons.cm-2 could not be analyzed because of crack. Samples that formed at pressure below than 6 tons.cm-2 had low hardness.