Na_3PO_4添加ハイドロキシアパタイトの微細組織とマイクロクラックの生成

概要

論文の詳細を見る
Hydroxyapatite, Ca_<10>(PO_4)_6(OH)_2, doped with 0.3 to 5.0 mass% Na_3PO_4 as external sintering aid was studied by transmission electron microscopy. Densification of the powder blend was performed by hot-pressing at 1200℃ for 30 min. The overall microstructure of the material was composed of homogenous, equiaxed hydroxyapatite grains with an average size of about 1.5 μm. Apart from the matrix grains, a sodium-plus calcium-containing secondary phase, β-NaCaPO_4, precipitated at triple pockets of few hundred nanometer scale. The occurrence of this precipitated phase was typically accompanied by microcrack formation. Microcrack opening typically occurred at one edge of the three or four visible phase boundaries. It should be emphasized that nearly all of the secondary phase pockets revealed such a microcrack. The microcrack formation process is likely to be governed by two interacting material characteristics the thermal expansion mismatch of the adjacent phases and the interface bonding strength.
社団法人日本セラミックス協会の論文
2001-03-01