Interactions between a leadless glaze and a biscuit fired bone china body during glost firing—part III: effect of glassy matrix phase

As the final part of the study, the interactions between a commercial leadless glaze and a simulated bone china body glass during glost firing at different temperatures have been investigated. Advanced techniques such as electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) have been employed in order to assess the contribution of the glassy phase of a biscuit fired bone china body to the formation of interaction layers at the interfaces independently. The results showed the presence of several calcium phosphate phases with distinct morphology at the glaze-simulated body glass interface for both the glost firing temperatures employed. It was suggested that the formation of the hydroxyapatite crystals at the glaze-biscuit fired bone china body interface may be helped by the glassy phase. TEM was found to be particularly useful since the interaction layers presented a most complicated and also interesting microstructure due in part to their multi-layered nature and small size of the calcium phosphate crystals situated at the interfaces.