Ceramics-Silikáty 51, (2) 112 - 118 (2007)

The crystallisation behaviour of calcium phosphate glass containing vanadium oxide was studied. Glass with a molar ratio of [CaO]/[P₂O₅] = 1.13 and a V₂O₅ content of 8 mol.% was prepared for the experiments. The crystallisation of bulk glass samples was performed under isothermal conditions at T = 650-820°C. The surface crystallisation mechanism of studied glass with dendritic growth of the primary α-Ca₂P₂O₇ phase was observed. In all crystallised samples, β-Ca₂P₂O₇ and VP₂O₇ appeared as the secondary phases. In the investigated temperature range, crystal growth rates 9 × 10⁻⁹ - 2.14 × 10⁻⁶ m/s were determined. The temperature dependence of the crystal growth rate makes possible to calculate activation energy E_a = 407 ± 30 kJ/mol of crystallization. The experimental data were compared with those estimated by using a theoretical model of the crystal growth rate and good agreement between the results was found.