Microwave sintering of plasma-sprayed yttria stabilized zirconia electrolyte coating

In this work, microwave (MW) was used to sinter atmospheric plasma-sprayed 8 mol% yttria stabilized zirconia (YSZ) electrolytes coatings. Three types of coatings were studied: pure YSZ coating, 5 wt% BaTiO3 filled YSZ coating and 10wt% BaTiO3 filled YSZ coating. Microstructures and ionic conductivities of as-sprayed and MW-sintered coatings were characterized. The results indicated that that the pure YSZ coating can hardly be sintered by the MW sintering and it can only be heated up to 900 degrees C. For two composite coatings, BaTiO3 particles distributed in the composite coating act as a good MW susceptor and thereby, a good heat source for sintering YSZ matrix. After a MW sintering at 1450 degrees C for about 30 min, an obvious structural modification was noticed: the lamellar and columnar crystal features of as-sprayed plasma-sprayed YSZ coatings were modified to equiax crystal in the sintered coatings. Ionic conductivity of sintered 5 wt% BaTiO3 filled YSZ composite coatings were elevated to about twice of as-sprayed coating. A further increase of BaTiO3 content to 10 wt% in the composite coating enhanced the sintering efficiency, however, the ionic conductivity of composite coatings was decreased. (c) 2008 Elsevier Ltd. All rights reserved.