Sintesis dan Karakterisasi Magnet Berbasis Barium Heksaferit - Alumina

Abstract

Permanent magnet based on BaFe12O19 - Al2O3 by powder metallurgy method has been made. Variables of the research is barium hexaferrite (BaFe12O19) materials added Al2O3 with variations in the composition of 100:0, 60:40, 50:50 and 40:60 (% weight) and the sintering temperature of 900, 950, 1000, 1050 and 1100 0C with holding time of 2 hours. Quantities observed were include density, porosity, flux density, hysteresis curve, microstructure analysis by XRD and SEM. From the observation indicate that the addition of Al2O3 to produce true density ranges from 3570 to 4450 kg/m3, green body density ranges from 2600 to 3270 kg/m3, bulk density ranges from 4030 to 5170 kg/m3, porosity ranges from 19.28 to 24.79%, shrinkage ranges from 2.37 to 10.92%, magnetic flux density ranges from 13.00 to 65.45 Gauss, remanence Br ranges from 0.03 to 0.20 kGauss, coercivity HCJ ranges from 0.082 to 0.096 kOe and BHmax ranges from 0.046 to 0.290 MGOe. Both materials are generally reacted, the resulting phase structure FeAl2O3, BaFeO3, Fe2O3, Ba3Al2O6 and Fe3O4. The morphology is relatively homogeneous with the particle shape resembles a rod with a particle size < 1 μm. The best composition and temperature is 40 %wt Al2O3 at a temperature of 1050 0C with a bulk density of 4340 kg/m3, porosity of 22.98%, shrinkage of 6.27% and flux density 63.00 Gauss. The resulting permanent magnet are soft magnetic expected to be used as recording media or microwave absorbent material

Telah berhasil dibuat magnet permanen berbasis BaFe12O19-Al2O3 melalui metode metalurgi serbuk. Variabel penelitian yang dilakukan adalah bahan barium heksaferit (BaFe12O19) ditambahkan Al2O3 dengan variasi komposisi 100:0, 60:40, 50:50 dan 40:60 (% berat), serta suhu sintering 900, 950, 1000, 1050 dan 1100 0C yang masing-masing ditahan selama 2 jam. Besaran-besaran yang diamati meliputi densitas, porositas, fluks densitas, kurva histerisis, analisa mikrostruktur dengan XRD dan SEM. Dari hasil pengamatan menunjukkan bahwa penambahan Al2O3 menghasilkan true density berkisar 3570-4450 kg/m3, green body density berkisar 2600-3270 kg/m3, bulk density berkisar 4030-5170 kg/m3, porositas berkisar 19,28-24,79%, shrinkage berkisar 2,37-10,92%, flux density magnetik berkisar 13,00-65,45 Gauss, remanensi Br berkisar 0,03-0,20 kGauss, koersivitas HCJ berkisar 0,082-0,096 kOe dan BHmax berkisar 0,046-0,290 MGOe. Kedua bahan sebagian besar bereaksi, struktur fasa yang dihasilkan FeAl2O3, BaFeO3, Fe2O3, Ba3Al2O6 dan Fe3O4. Sedangkan morfologinya relatif homogen dengan bentuk partikel menyerupai batang dan ukuran partikel < 1 μm. Komposisi dan suhu optimum adalah 40% wt Al2O3 pada suhu 1050 0C dengan menghasilkan bulk density 4340 kg/m3, porositas 22,98%, shrinkage 6,27% dan flux density 63,00 Gauss. Magnet permanen yang dihasilkan bersifat soft magnetik yang diharapkan dapat digunakan sebagai media recording atau material absorben microwave.