Firing of Hydroxyapatite in Oxygen Atmosphere

Abstract

Oxygen adsorbed to Hydroxyapatite (HAp) after firing at 1200°C in oxygen atmosphere has been measured by Thermal Desorption Spectrometer (TDS). The quantity of adsorption oxygen has been determined by weight change of HAp at firing. HAp adsorbs oxygen in two different states. These two states correspond to HAp coloring phenomenon (HAp crystal structure). In case of the reddish-brown type HAp (Hexagonal HAp), it adsorbs oxygen as ionized molecule which weight is 0.2 mass% of HAp. As for the red type HAp (Monoclinic HAp), it adsorbs 0.4 mass% oxygen of the weight. In addition, with firing in argon atmosphere, it is measured 0.4 mass% weight change at white type HAp (Monoclinic HAp). In sintering high density HAp pellet, oxygen atmosphere accelerated densification. This pellet appeared transparent and its density was 99.69%.