[19p-E303-1~8] 3.7 Laser processing

[19p-E303-3] Improvement of crystallinity for hydroxyapatite coating by small size ablated particles

〇Hidehiko Yashiro¹, Nobuhiro Umebayashi¹, Masayuki Kakehata¹ (1.AIST-ESPRIT)

Keywords:Pulsed Laser Deposition, Laser ablation, Hydroxyapatite

Hydroxyapatite (HAp) coating gives bone conductivity for implant materials as alloy and ceramics. We study HAp polycrystal coating on a zirconia implant by pulsed laser deposition method. b-TCP target is irradiated by a 4^th harmonics of YAG laser. Deposited materials change 80 % from amorphous CaP to HAp polycrystal in 0.15 torr H₂O gas atmosphere on the surface at 500 C. This ratio of HAp crystal decreases as increase of gas pressure. This result shows that tiny ablated materials as atoms, ions, and molecules are stopped at short range as increasing of gas pressure. In order to understand only small size of particles are deposited on the zirconia substrate geometrically. The surface temperature is controlled from room temperature to 600 C. The crystallin of deposited layers is evaluated by a Raman spectrometer. The center of Raman spectral line around 960 cm^-1 shifts and the line width changes drastically narrower at around 390 C. This indicate that the amorphous CaP completely changes to HAp polycrystal.