Experimental liquidus studies of the Pb-Fe-Ca-O system in air

Phase equilibria of the Pb-Fe-Ca-O system have been investigated at 1043-1653\ua0K (770-1380\ua0°C) for oxide liquid in equilibrium with air and solid oxide phases: (a) hematite FeO; (b) spinel (Fe,Ca)FeO; (c) calcium ferrites CaFeO, CaFeO, CaFeO; (d) lead ferrites (magnetoplumbite (Pb,Ca)O·12FeO, plumboferrite (Pb,Ca)O·(5 + x)FeO, 1:1 lead ferrite (Pb,Ca)O·(1 ± x)FeO); (e) lead oxide PbO (massicot); (f) calcium plumbate CaPbO; and (g) lime CaO. High-temperature equilibration on inert metal (platinum, gold) substrates, followed by quenching and direct measurement of Pb, Fe and Ca concentrations in the phases with the electron probe x-ray microanalysis (EPMA) has been used to accurately characterize the system in equilibrium with air. All results are projected onto the PbO-“FeO”-CaO plane for presentation purposes. The present study is the first systematic characterization of liquidus over a wide range of compositions in this system in equilibrium with air