Morphology Modification of Barium Hexaferrite to Nanorod Particle Using Chitosan and Starch as Template

Abstract

Barium hexaferrite is known as a permanent magnet that has hexagonal or granules morphologies. Magnetic field of barium hexaferrite can be increased by changing its morphology. A rod-shaped barium hexaferrite is expected to result in higher magnetic field compared to granules even though the volumes of both are the same. This study aims to synthesize a rod-shaped barium hexaferrite and to evaluate its magnetic properties. Barium hexaferrite was synthesized using sol-gel method by mixing barium nitrate and iron (III) nitrate nonahydrate with molar ratio of 1:12. Chitosan 1% was added as dispersant and starch 0.5% (w/v) was used as template with variation in volume (5%, 10% and 15% (v/v)). The solution was dried at 100°C for 48 hours and resulting xerogel was then calcined at 1000°C for 2 hours to obtain barium hexaferrite powder. X-Ray D result demonstrated the presence of barium hexaferrite with small fraction of hematite and pure barium hexaferrite. Scanning electron microscopy images showed different concentrations of starch generated different size and morphologies of resulting barium hexaferrite. A rod shaped barium hexaferrite was formed for all samples that prepared using starch template, however hexagonal shape was still found in all samples. The size of resulting barium hexaferrite is decrease by increasing the concentration of starch. Theparticle size of barium hexaferrite measured was 125nm thickness with of 500nmlength for 5% starch, 109 nm thickness and 406 nm length for 10% starch and 62.5 nm thickness and 406 nm length for 15% starch, Barium hexaferrite synthesized without using starch and chitosan produced hexagonal morphology with the thickness of 240-574 nm and length of 574-957 nm. Vibrating Sample Magnetometer showed hysteresis curve as the percentage variation of starch was used, higher amount of starch used tends to increase the values of saturation and remanence. Avery significant increase in coercivity value amounted to 457.1% occurred in the use of 10% starch. It can be concluded that starch can be used as rod-shaped template in sol-gel method to produce barium hexaferrite. By using chitosan and starch in the process of synthesis of barium hexaferrite using sol-gel method can increase the value of the magnetization and the coercivity barium hexaferrite.