Densification of LaGaO3 at low sintering temperatures via Fe3+ substitution at Ga3+ site

Attempts to achieve near theoretical density in polycrystalline LaGaO3 comp acts using Fe2O3 as a dopant have been made. The B-site substituted lanthan um gallates with iron doping ranging from 15 to 55 mole% FeO1.(5) (Fe2O3) w ere synthesized via solid state reaction using oxide and nitrate precursors and sintered at 1200 degreesC for 24 to 72 h and at 1300 degreesC for 12 t o 36 h. Systematic variation in the lattice constants and microstructural a spects was followed as a function of mole fraction of Fe2O3. It was found t hat the parent LaGaO3 structure could take up as high as 55 mole% of Fe2O3 retaining the orthorhombic crystal structure. Compositions containing 35 mo le% Fe2O3 soaked for 48 h or more at 1200 degreesC and for as low as 12 h a t 1300 degreesC resulted in perfectly dense compacts. Bodies containing low er dopant concentrations (x(Fe2O3) less than or equal to 0.25) were found t o have a substantial degree of porosity with good intergranular connectivit y, while a significant amount of grain growth and broad grain size distribu tion was an interesting feature in samples containing mole fractions higher than 0.35. (C) 2001 Kluwer Academic Publishers.