| Summary: | 碩士 === 義守大學 === 材料科學與工程學系碩士班 === 93 === A chemical reaction method was used to study the formation mechanisms of hydroxyapatite or calcium phosphate salts on the surface of different ceramic substrates, through controlling different concentrations of Ca2+、PO43- and OH- in the aqueous solution. In this study, sintered Ca3-(PO4)2, Al2O3 and ZrO2 ceramic composites were fabricated to be plate-like substrates for this particular chemical coating process. In the chemical coating or reacting process, different ceramic substrates were dipped in the 1 M H3PO4 aqueous solution at T=25~80℃ and pH=0.7~11, to observe phase existence and microstructure of surface coating. Surface coating was formed to be CaHPO4?2H2O (DCPD) after the Ca3(PO4)2 substrate was dipped in the 1 M H3PO4 aqueous solution at pH=2.5 under a sufficient Ca2+ source from Ca(OH)2 . The surface coating of DCPD was further treated in the alkaline solution, 2.5 M NaOH and it was further transformed into hydroxyapatite. From experimental results, HA was formed easily at a higher pH value. As the pH value increased, the surface morphology of these coatings were changed into the network structure from the initial plate structure. In the Al2O3/Ca3(PO4)2 and ZrO2/Ca3(PO4)2 composite substrates, HA was much easier to form in the alkaline solution when the volume ratio of Ca3(PO4)3/Al2O3 or Ca3- (PO4)2/ ZrO2 was 7/3.
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