Interactions between an ABS type leadless glaze and a biscuit fired bone china body during glost firing. Part I: preparation of experimental phases

In this paper, part of an extended study, crystalline phases of a biscuit fired bone china body, namely anorthite and beta-tricalcium phosphate (β-TCP), were produced experimentally to be used in subsequent interface studies for simulation of the interactions during glost firing at different temperatures between an ABS type commercial leadless glaze and the individual phases originally present in the body. The research was undertaken based on the premise that bone china has been a product providing the greatest challenge in moving to a totally leadless glaze. High bulk density and low apparent porosity values were achieved from both the anorthite and β-TCP samples through the suitable heat treatments. The microstructural and chemical characteristics of the experimental phases were studied using X-ray diffraction (XRD), scanning (SEM), and transmission (TEM) electron microscopy techniques in combination with EDS analysis. The morphological and chemical similarity of the phases to those originally present in a biscuit fired bone china body was clearly demonstrated. This similarity supports the choice of the experimental material for the interface studies undertaken with these phases in the second part of the study.