Mechanisms of Sintering of Different Hydroxyapatite Powders and Low-Melting Sodium-Borosilicate Glass

Abstract

The paper analyzes the sintering of powders consisting of three types of calcium phosphates with S–B–Na glass powder under the same process conditions. It is concluded that a liquid phase, represented by the glass melt, shows up in the sintering of the glass with biogenic or synthetic hydroxyapatite or a mixture of synthetic phosphates. The substantial pore formation in the sintering process is mainly due to the removal of carbon oxides or water vapors that result from the decomposition of basic components of the glass charge and its boiling. Parameters of grain and porous microstructures of the ceramics are presented before and after the first and second sintering processes. The mechanical strength and biosolubility of the ceramic samples are indicated as well.