Sintering and electrical properties of the perovskite system (La,Ca) (Cr,Co) O₃

<p>"The solid solutions of La_1-xCa_xCr_1-yCo_yO₃ were investigated in an effort to develop an interconnect and cathode materials for solid oxide fuel cells.</p> <p>Sintering studies were done in air at temperatures below 1500° C. Significant improvements in densification was observed with the substitution of 20 m% Co for Cr due to the presence of a liquid phase. A density of 96 % of theoretical was achieved in air at 1400° C with the substitution of 20 m% Ca for La and 10 m% Co for Cr.</p> <p>Electrical conductivity DC measurements were made as a function of temperature and oxygen activity. At 1000° C and 1 atm. oxygen the electrical conductivity ranged from 17 to 51 S/cm for La_0.9Ca_0.1Cr_0.9Co_0.1O₃ and La_0.7Ca_0.3Cr_0.9Co_0.1O₃, respectively. The conductivity showed thermal activation for all compositions. Under oxidizing conditions the concentration of carriers was directly proportional to the Co and Ca content. All of the compositions showed similar dependence of conductivity on the oxygen activity. Dependence was small at high oxygen activities; as oxygen activity decreased, a break in electrical conductivity at 10^-10 atm. and 1000° C was observed, then the electrical conductivity decreased as P_O₂^1/4. A positive Seebeck coefficient was observed for all the compositions indicating p-type conductivity.</p> <p>Sintering, electrical conductivity, thermal expansion and stability studies indicate that La_1-xCa_xCr_0.9Co_0.1O₃ with x = 0.1 - 0.3 appears to be a candidate for SOFC applications"--Abstract, page ii.</p>

Name thesis:degree_name

Ph. D. in Ceramic Engineering

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Koc, Rasit

• Ceramic Materials

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/757

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1759