Low‐Temperature Pressureless Sintering of Sr‐ and Mg‐Doped Lanthanum Gallate Ceramics by Sintering Atmosphere Control

The present investigation reports a new processing technique that can reduce the sintering temperature of Sr‐ and Mg‐doped lanthanum gallate (LSGM), a good candidate material for the electrolyte of the solid oxide fuel cell (SOFC). When LSGM was sintered at 1623 K for 5 h in N 2 or O 2 , the samples were densified over 98% relative density. In contrast, only 93% relative density was achieved after sintering in air, the conventional sintering atmosphere. As a result of better densification in N 2 or O 2 , the electrical conductivity of the N 2 ‐sintered and air‐annealed or the O 2 ‐sintered sample was higher than that of the air‐sintered sample by 30%. This result shows the beneficial effect of N 2 or O 2 sintering of LSGM and provides a high possibility of a low‐temperature preparation of an LSGM‐based SOFC.