Deposition of Hydroxyapatite on Titanium Plate by Microarc Anodizing and Hydrothermal Treatment
Date Issued
2005
Date
2005
Author(s)
Liu, Jian-Hong
DOI
zh-TW
Abstract
Calcium and phosphorus-containing oxide film was made on commercially pure titanium plate using a microarc discharging oxidation method. The microstructure of the oxide film was characterized by cross-sectional transmission electron microscopy (TEM). Hydrothermal treatment was then performed on the oxide film for the precipitation of hydroxyapatite. Upon galvanostatic anodizing up to 350V at a current density of 50 mA/cm2 in the electrolyte consisting of β-glycerophosphate disodium(β-GP) and calcium acetate, microarc discharge was observed on titanium plates, leading to the formation of an oxide film mainly composed of anatase, and calcium and phosphorus species. Once microarc discharge occurred during anodizing, relatively large craters were observed on the oxide film, which generally comprised two layers:an outer overlay containing significant amount of Ca and P in a mixture of amorphous oxide and nanocrystalline anatase, and an inner oxide layer dotted with micropores contacting the substrate. Moreover, as the front of the oxide film propagated toward the substrate, these micropores tended to coalesce into cavities residing at the interface between the outer and inner layers. The oxide film contained more Ca and P, but lower Ca/P ratio, and displayed less crystallinity with increasing solution b-GP concentration. Both acetate and hydroxyl ions can enhance microarc discharging, while resulted in oxide films with different morphologies and crystal structure. Hydroxyapatite precipitates on the porous oxide film were nonuniform after 2 h of hydrothermal treatment at 300℃. In contrast, introducing sodium hydrocarbonate to hydrothermal treatment solution led to the formation of high density hydroxyapatite precipitates with improved crystallinity.
Subjects
微弧放電氧化
水熱處理
氫氧基磷酸鈣
橫截面微結構
microarc discharging oxidation
hydrothermal treatment
cross-sectional microstructure
Type
thesis
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