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

Abstract

Electrical contact pastes of composition (La 0.90 Sr 0.10 ) 0.98 MnO 3 + δ (LSM-10) formed strong bonds (∼3 MPa) to (Co,Mn) 3 O 4 spinel-coated Crofer 22 APU ferritic steel coupons when exposed to alternating flows of air and nitrogen (10 ppm O 2 ) 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 (La 0.80 Sr 0.20 ) 0.98 MnO 3 + 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.

LaCo0.6Ni0.4O3−δ as cathode contact material for intermediate temperature solid oxide fuel cells

“…Cr in the oxide scale will reacts with Sr in the contact material to form resistive SrCrO 4 phase or replaces the B-site element in perovskite structure to form Cr-containing perovskites [14,21,22]. In order to prevent dimension shrinkage of the contact layer during operation and enhance its adhesion to the oxide scale of the interconnect, pre-sintering of the contact layer in a low oxygen partial pressure atmosphere was found to be effective [11,23]. LaCo x Ni 1Àx O 3 (LCN) perovskite was examined previously as the cathode material.…”

Effects of non magnetic aluminum Al doping on the structural, magnetic and transport properties in La0.57Nd0.1Sr0.33MnO3 manganite oxide

“….) have been widely investigated due to their remarkable physical and chemical properties, their potential applications in technology, their unusual colossal magnetoresistive (CMR) property as well as their magnetocaloric effect (MCE) [1][2][3][4]. The parent compound, REMnO 3 is a charge-transfer (CT) insulator with trivalent manganese in different layers coupled among themselves antiferromagnetically through a superexchange mechanism.…”

Low‐Temperature Densification of Lanthanum Strontium Manganite (La1−xSrxMnO3+δ), x=0.0–0.20

“…Lanthanum manganites have also been applied as protective coatings on ferritic steel interconnects in fuel cells in order to inhibit the growth of a resistive scale and to decrease chromium volatilization 3–6 . Another fuel cell application for LSM is as a contact paste, aimed at lowering the resistance of electrical contacts between the metallic interconnect and the cathode 7–10 …”

“…Accelerated shrinkage was related to transients in oxygen nonstoichiometry and the associated cation vacancy concentrations induced by this treatment 20 . Similar methods were applied as a means of processing LSM‐10 contact pastes for SOFCs, where strong, low‐resistance bonds between LSM‐20 cathodes and spinel‐coated ferritic steel interconnects were formed at 900°C, without simultaneous densification of the cathode 10 …”

“…[3][4][5][6] Another fuel cell application for LSM is as a contact paste, aimed at lowering the resistance of electrical contacts between the metallic interconnect and the cathode. [7][8][9][10] The sinterability of LSM in air has been extensively investigated and shown to improve with A-site deficiency and low amounts of strontium substitution. [11][12][13] Sintering temperatures of LSM have been lowered further by the partial substitution of cobalt for manganese and by tailoring the particle size distribution, 9 for example, although temperatures of at least 12001C are typically needed to achieve a high sintered density.…”