SYNTHESIS OF MFe 12 O 19 (M=Ba,Sr) HEXAFERRITE NANO-PARTICLE USING CO-PRECIPITATION METHOD

Abstract

Synthesis of MFe 12 O 19 (M=Ba,Sr) hexaferrite nano-particle using co-precipitation method has been done. Base materials used has a high purity according to Merck catalog of Ba(NO 3 ) 2 .6H 2 O, Sr(NO 3 ).6H 2 O, dan Fe(NO 3 ) 3 .9H 2 O powders. In co-precipitation method Ba(II), Sr(II) and Fe(II) hydroxide precursors were precipitated during the reaction between the aqueous solution of metal nitrates and 1-M aqueous solution of natrium hydroxide, which served as a precipitating reagent. The precipitation was performed at 45 °C and pH value of 12.6 respectively. Sintering process of the precursor was done at the various temperature of 900 and 1000°C for 5 hours respectively. Phase identification was measured bymeans of x-rays diffraction. The magnetic properties change before and after sintering process was measured by vibrating sample magnetometer. The microstructure of the powder sample was observed by scanning electron microscope. Under the order of x-rays diffraction patterns could be reveal that both of the samples have established the crystal system of BaFe 12 O 19 and SrFe 12 O 19 hexaferrite characterized by the presence of a sharp intensity peak. Impact of the sintering process to the phase system of BaFe 12 O 19 and SrFe 12 O 19 is clearly visible on changing of the magnetic properties, namely intrinsic magnetic coercivity and magnetic remanence which is increased sharply after sintering process. Increase in both parameters indicates that the precursor has undergone a process of crystallization into the BaFe 12 O 19 and SrFe 12 O 19 hexaferrite phase system. Magnetic remanence and intrinsic coercivity of BaFe 12 O 19 successively obtained about 30.3emu/g and 4.7kOe higher than the magnetic remanence and intrinsic coercivity of SrFe 12 O 19 that only 22.9emu/g and 3.5kOe. This increasing the value of the intrinsic magnetic coercivity is closely related to the size of the BaFe 12 O 19 crystallites more subtle. Keywords: Nano-particels, Co-precipitation, Coercivity intrinsik, Remanence.