Preparation of High Density Perovskite LaNiO<sub>3</sub> by Using HIP

Abstract

The authors have succeeded to prepare dense sintered bodies of perovskite LaNiO3, which shows a metallic conduction, by HIPping without flux such as Na2CO3. The stoichiometric mixture of La2O3 and NiO was precalcined in air at 900°C for 5h. The ground sample was then sintered at 1100° or 1300°C in air for 20h. The sintered bodies were composed of La2NiO4 and NiO, and had the densities of up to 95%. The single phase perovskite LaNiO3 of 95% density was obtained from its presintered body by HIPping under 101MPa (in Ar gas containing 20% oxygen) and 1400°C for 2h. A very low resistivity of 2.2×10-6Ω⋅m was measured for this HIPped body of LaNiO3. The stability region for the perovskite compound LaNiO3 in P-T diagram was discussed.