ENHANCED CRYSTALLIZATION OF APATITE ON ELECTRICALLY POLED SURFACES

摘要

Electrical polarization was found to enhance the bone-like crystal and hetero-crystal (K_2SO_4) growth on hydroxyapatite (HAp) ceramics in a simulated body fluid and an alum solution, respectively. This enhancement was observed on the negatively polarized surface, while the crystal growth was restricted to the positively polarized surface. This polarization effect was more effective on the ceramic specimens sintered in a steam stream than on those sintered in air. The dielectric properties of these HAp ceramics were investigated. Based on these results and a spectroscopic analysis, the effect was attributed to the condensation of Ca~(2+) ions on the polarized surface due to the reorientation of the lattice hydroxide ions.