ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optical Transmissivity Changes of Thin Hydroxyapatite Sheets on Heating

J. Majling, Š. Svetík, J. Annus, J. Krištín, and Pm. Marquis

Department of Ceramics, Glass and Cement, Faculty of Chemical Technology, Slovak University of Technology, SK-812 37 Bratislava

Abstract: Thin hydroxyapatite sheets, consisting either of superfine hydroxyapatite particles or particles increased in size by hydrothermal treatment, have been fabricated by a modified pressure casting procedure. The sheets were fairly well transparent after their fabrication and drying. On heating to 1000°C the samples of superfine particles became opaque while the samples of hydrothermally treated gels remained essentially transparent.By measuring the optical transmissivity of sheet preforms during their constant rate heating it is possible to determine the temperature interval in which the transition or partial transition between the transparent and the opaque state takes place.Dilatometric measurements show an expansion of samples above 1000°C, which is undoubtedly connected with creation of pores. Pore creation may be the reason also for the decrease of the transmissivity of specimens above ca. 750° C.

Full paper in Portable Document Format: 515a268.pdf

Chemical Papers 51 (5) 268–272 (1997)