Phase analysis and microstructure evolution of a bone china body modified with scrap addition

Properties of a commercial bone china body containing varying amount of fired scrap of same material (0–12%) was studied and attempt was made to correlate the same with respect to phase analysis and microstructural evolution. Despite numerous studies on bone china by several authors, knowledge is still insufficient about the chemical reactions taking place among the various raw materials leading to very narrow firing range. In commercial production of bone china wares, loss during biscuit firing is significantly high. In this study attempt has been made to utilize a portion of the fired scrap in a commercial bone china composition and the effect of the same on the formation of the constituent phases has been tried to correlate with the properties developed. Phase analysis of the matured specimens revealed that there was gradual decrease in β-Tri calcium phosphate (β-TCP) content while increase in glassy phase was observed with progressive incorporation of scrap. Scrap incorporated body resulted in early maturity of the specimens as well as development of a very dense microstructure. Presence of scrap did not alter the anorthite phase content. The microstructure consisted of distinct regions of agglomerated spheroidal β-TCP and lath shaped anorthite crystallites in a heterogeneous calcium aluminosilicate glassy matrix.