J. Korean Ceram. Soc. > Volume 52(5); 2015 > Article
 Journal of the Korean Ceramic Society 2015;52(5): 374. doi: https://doi.org/10.4191/kcers.2015.52.5.374
 Fabrication and Characterization of Hydroxyapatite/Mullite and Tricalcium Phosphate/Al2O3 Composites Containing 30 wt% of Bioactive Components Jung-Soo Ha School of Materials Science and Engineering, Andong National University ABSTRACT Mullite-matrix and $Al_2O_3$-matrix composites were fabricated with 30 wt% hydroxyapatite (HA) and tricalcium phosphate (TCP), respectively, as additives to give bioactivity. A diphasic gel process was employed to lower the densification temperature of the mullite matrix to $1320^{circ}C$. A polymer complexation process was used to synthesize a TCP powder that was fully densified at $1250^{circ}C$, for application to the matrix. For the HA/mullite composite, HA decomposed during sintering by reactions with the matrix components of $Al_2O_3$ and $SiO_2$, resulting in a mixture of $Al_2O_3$, TCP, and other minor phases with a low densification of less than 88% of the theoretical density (TD). In contrast, the TCP/$Al_2O_3$ composite was highly densified by sintering at $1350^{circ}C$ to 96%TD with no reaction between the components. Different from the TCP monolith, the TCP/$Al_2O_3$ composite also showed a fine microstructure and intergranular fracture, both of which characteristics are advantageous for strength and fracture toughness. Key words: Hydroxyapatite, Mullite, Tricalcium phosphate, $Al_2O_3$, Composites
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