The devitrification behavior of calcium phosphate glass with TiO2 addition

The effects of TiO2 addition on the devitrification behavior of the calcium phosphate glasses were investigated using thermal analysis techniques. Both the DTA traces of coarse powder and fine powder for calcium phosphate glasses indicated that the glass transition temperature (T-g), gradually increased. To determine whether the devitrification begins at the surface or in the bulk of these glasses, we recorded DTA curves of coarse powder and fine powder. By comparing the exothermic peak temperature of coarse powder and fine powder, we found that the two exothermic peak temperatures tend to be neater when the amount of TiO2 in calcium phosphate is increased. This indicates that bulk devitrification or, more appropriately, devitrification at the internal interface is easier, i.e., TiO2 is an effective nucleating agent in these glass systems. (C) 1999 Published by Elsevier Science B.V. All rights reserved.