Effect of pH Variation on the Properties of the Hydroxyapatite Precipitates and Powder Prepared by the Wet Method

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J. Korean Ceram. Soc. > Volume 26(2); 1989 > Article

Journal of the Korean Ceramic Society 1989;26(2): 157.

습식법으로 제조한 수산화아파타이트 침전입자와 분말의 특성에 미치는 pH변화의 영향

신용규, 정형진, 김병호¹

한국과학기술원 무기재료연구실
¹고려대학교 재료공학과

Effect of pH Variation on the Properties of the Hydroxyapatite Precipitates and Powder Prepared by the Wet Method

ABSTRACT

The effect of pH variation in starting solution on the characteristics of hydroxyapatite precipitates and powder prepared by the wet method was investigated. Hydroxyapatite precipitates was agglomerated, the average agglomerated particle size was decreased in the range from 2 to 6${mu}{textrm}{m}$ with increasing pH values in starting solution. The aspect ratio of rod-shaped hydroxyapatite particle was rapidly increased at pH 11 and 11.5. The maximum specific surface area, 91.1$m^2$/g, was at pH 10.5. Dried powder prepared at high pH values contained more minutes CO2 than that prepared at low pH values. The poor crystallinity was maintained up to $600^{circ}C$ regardless of the pH values in starting solutions. However, the second phase or high crsytalline hydroxypatite phase appeared above 80$0^{circ}C$. In pH 9.5 and pH 10, $beta$-whitlockite transformed to $alpha$-whitlockite at 120$0^{circ}C$, while in pH 10.5-11.5, hydroxyapatite phase was maintained up to 120$0^{circ}C$.