Phase Evolution of Yttrium Iron Garnet (YIG) Made by Solid State Sintering: Particle Size Effect

Abstract

The phase evolution of yttrium iron garnet (YIG) during reaction 3Y 2 O 3 -5Fe 2 O 3 was investigated by modifying Fe 2 O 3 particle sizes (FPS). Five different sizes of Fe 2 O 3 , (d 50 ) are used to prepare YIG powder. Solid state reaction (SSR) was applied at 1200 °C in order to gain insight on the effect of FPS towards the YIG formation. Rietveld refinement method was used to quantify the amount of YIG yielded (%). Larger FPS (> 50 μm) initiates only 5Fe 2 O 3 + 3Y 2 O 3 à 3YFeO 3 + Fe 2 O 3 + Y 3 Fe 5 O 12. . However, when the fine FPS (5 μm) is used, the reaction pathway was changed into 5Fe 2 O 3 + 3Y 2 O 3 à 6YFeO 3 + 2Fe 2 O 3 à 2Y 3 Fe 5 O 12. These behaviors is explained that the smaller FPS consumed quickly to form YIG due to the smaller particle distance between Fe 2 O 3 and Y 2 O 3 . This shall be leading to higher reaction rates (mass-transfer kinetics).