Synthesis And Sintering Of Lanthanum Chromite Powders

Lanthanum chromite powders doped with Sr, Ca or Mg have been widely accepted as the candidate materials for interconnection materials in Solid Oxide Fuel Cells (SOFCs). Various chemical routes have been used to synthesize lanthanum chromite powders. However, most of the powders obtained from these chemical processes appeared poorly sinterability. In this paper, the preparation of lanthanide chromium bimetallic alkoxide and perovskite LaCrO₃ powders by the metal alkoxide hydrolysis methods were investigated. Lanthanide chromium bimetallic alkoxide was prepared from anhydrous lanthanum trichloride, chromium trichloride tri-tetrahydrofuranate and metal lithium in a mixture of anhydrous n-butanol and benzene. Monodispersed spherical particles, with average diameters of 0.25μm, have been obtained via the hydrolysis of alkoxide precursors. The powders transformed to monoclinic LaCrO₄ and orthorhombic LaCrO₃ phases at about 400°C. A pure orthorhombic perovskite phase LaCrO₃ was obtained above 600°C. The powders were sintered in air at a temperature range of 1300°C～1600°C. A maximum relative density of 94.2% was achieved.