Low-temperature sintering of lanthanum strontium manganite-based contact pastes for SOFCs

Electrical contact pastes of composition (La0.90Sr0.10)0.98MnO3 + δ (LSM-10) formed strong bonds (~3 MPa) to (Co,Mn)3O4 spinel-coated Crofer 22 APU ferritic steel coupons when exposed to alternating flows of air and nitrogen (10 ppm O2) at 900 °C for 2 h or longer. When held at 900 °C in air only, bond strengths were negligible. Substantial bonds could also be created between LSM-10 contact paste and (La0.80Sr0.20)0.98MnO3 + δ (LSM-20) porous cathodes by processing in alternating air and nitrogen, without simultaneous densification of the cathode. Enhanced sintering of LSM-10 is attributed to transients in the defect structure induced by oxygen partial pressure changes.