Experimental Liquidus Studies of the Pb-Fe-Si-O System in Equilibrium with Metallic Pb

Phase equilibria of the Pb-Fe-Si-O system have been investigated at 943 K to 1773 K (670 degrees C to 1500 degrees C) for oxide liquid in equilibrium with liquid Pb metal and solid oxide phases: (a) quartz, tridymite, or cristobalite; (b) (fayalite + tridymite) or (fayalite + spinel); (c) spinel (Fe3O4); (d) complex lead-iron silicates (melanotekite PbO center dot FeO1.5 center dot SiO2, barysilite 8PbO center dot FeO center dot 6SiO(2), 5PbO center dot FeO1.5 center dot SiO2, and 6PbO center dot FeO1.5 center dot SiO2); (e) lead silicates (Pb2SiO4, Pb11Si3O17); (f) lead ferrites (magnetoplumbite Pb1+x Fe12-x O19-x solid solution range); and (g) lead oxide (PbO, massicot). High-temperature equilibration on primary phase or iridium substrates, followed by quenching and direct measurement of Pb, Fe, and Si concentrations in the phases with the electron probe X-ray microanalysis, has been used to accurately characterize the system in equilibrium with Pb metal. All results are projected onto the PbO-FeO-SiO2 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 metallic Pb.