Densification of Calcium-Deficient Hydroxyapatite by Hot Isostatic Pressing

Soo Ryong KIM; Kazushi HIROTA; Fujio P. OKAMURA; Yasutoshi HASEGAWA; Soon Ja PARK

doi:10.2109/jcersj.98.257

Soo Ryong KIM, Kazushi HIROTA, Fujio P. OKAMURA, Yasutoshi HASEGAWA, Soon Ja PARK

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Keywords: Calcium-deficient hydroxyapatite, Crystal water, Densification, HIP, Hydroxyapatite, Non-stoichiometric hydroxyapatite, Residual strain

JOURNAL FREE ACCESS

1990 Volume 98 Issue 1135 Pages 257-263

DOI https://doi.org/10.2109/jcersj.98.257

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Abstract

Stoichiometric and non-stoichiometric hydroxyapatites (Ca/P=1.55, 1.60 and 1.67), prepared by the hydrolysis of brushite or monetite, were densified by the HIP treatment at 100°-800°C and 320-850MPa. The temperature-pressure region for densification depends on Ca/P ratios. At 600MPa, the lowest temperature of the densification is 300°C for Ca/P=1.55, 400°C for 1.60 and 800°C for 1.67. In the case of calcium-deficient hydroxyapatite, the densification temperature decreased with increasing crystal water content. In the case of Ca/P=1.55, the lowest temperature for densification is 500°C at 600MPa for fully dried starting powder, of which “n” in Ca_10-xH_x(PO₄)₆(OH)_2-x⋅nH₂O is nearly equal to zero.

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