Microstructure control of Ce-TZP/Ba ferrite composites using an amorphous precursor of the second phase

Abstract

Composites consisting of Ce-TZP matrix and in situ-grown particles of barium ferrite (BaM) were prepared using various starting materials. For the starting material for the second phase, an amorphous precursor powder of BaM was prepared by coprecipitation and calcination. Uniform hematite particles were also prepared using liquid-phase synthesis under hydrothermal conditions. The Ce-TZP/20 wt % BaM composites were prepared by sintering the mixed powders of Ce-TZP, barium carbonate, hematite, and amorphous precursor of BaM. The aspect ratio of the in situ-grown BaM particles increased concomitantly with an increase in the mixing ratio of the amorphous precursor powder. The exaggerated grain growth of the BaM in the Ce-TZP matrix was efficiently suppressed by the addition of a small amount of barium carbonate and hematite to the amorphous precursor of BaM.