\"The solid solutions of La1-xCaxCr1-yCoyO3 were investigated in an effort to develop an interconnect and cathode materials for solid oxide fuel cells.
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.
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 La0.9Ca0.1Cr0.9Co0.1O3 and La0.7Ca0.3Cr0.9Co0.1O3, 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 PO₂1/4. A positive Seebeck coefficient was observed for all the compositions indicating p-type conductivity.
Sintering, electrical conductivity, thermal expansion and stability studies indicate that La1-xCaxCr0.9Co0.1O3 with x = 0.1 - 0.3 appears to be a candidate for SOFC applications\"--Abstract, page ii.
","abstract_html":"<p>"The solid solutions of La<sub>1-x</sub>Ca<sub>x</sub>Cr<sub>1-y</sub>Co<sub>y</sub>O<sub>3</sub> 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<sub>0.9</sub>Ca<sub>0.1</sub>Cr<sub>0.9</sub>Co<sub>0.1</sub>O<sub>3</sub> and La<sub>0.7</sub>Ca<sub>0.3</sub>Cr<sub>0.9</sub>Co<sub>0.1</sub>O<sub>3</sub>, 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<sup>-10</sup> atm. and 1000° C was observed, then the electrical conductivity decreased as P<sub>O₂</sub><sup>1/4</sup>. 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<sub>1-x</sub>Ca<sub>x</sub>Cr<sub>0.9</sub>Co<sub>0.1</sub>O<sub>3</sub> with x = 0.1 - 0.3 appears to be a candidate for SOFC applications"--Abstract, page ii.</p>","abstract_has_math":false,"creators":["Koc, Rasit"],"institution":"University of Missouri--Rolla","degree_name":"Ph. D. in Ceramic Engineering","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-02-10T08:00:00Z","date_published":"2016-02-10T08:00:00Z","updated_at":"2026-07-24T03:19:54Z","subjects":["Ceramic Materials"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/757","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Koc, Rasit"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-10T08:00:00Z"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation - Restricted Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D. in Ceramic Engineering"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Missouri--Rolla"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ceramic Materials"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsmine.mst.edu/doctoral_dissertations/757"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["\"The solid solutions of La1-xCaxCr1-yCoyO3 were investigated in an effort to develop an interconnect and cathode materials for solid oxide fuel cells.
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.
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 La0.9Ca0.1Cr0.9Co0.1O3 and La0.7Ca0.3Cr0.9Co0.1O3, 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 PO₂1/4. A positive Seebeck coefficient was observed for all the compositions indicating p-type conductivity.
Sintering, electrical conductivity, thermal expansion and stability studies indicate that La1-xCaxCr0.9Co0.1O3 with x = 0.1 - 0.3 appears to be a candidate for SOFC applications\"--Abstract, page ii.
"]},{"key":"dc:title","label":"Title","values":["Sintering and electrical properties of the perovskite system (La,Ca) (Cr,Co) O₃"]}]}],"canonical_facts":{"dc:creator":["Koc, Rasit"],"dc:date.available":["2016-02-10T08:00:00Z"],"dc:description.abstract":["\"The solid solutions of La1-xCaxCr1-yCoyO3 were investigated in an effort to develop an interconnect and cathode materials for solid oxide fuel cells.
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.
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 La0.9Ca0.1Cr0.9Co0.1O3 and La0.7Ca0.3Cr0.9Co0.1O3, 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 PO₂1/4. A positive Seebeck coefficient was observed for all the compositions indicating p-type conductivity.
Sintering, electrical conductivity, thermal expansion and stability studies indicate that La1-xCaxCr0.9Co0.1O3 with x = 0.1 - 0.3 appears to be a candidate for SOFC applications\"--Abstract, page ii.
"],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/757"],"dc:subject":["Ceramic Materials"],"dc:title":["Sintering and electrical properties of the perovskite system (La,Ca) (Cr,Co) O₃"],"dc:type":["Dissertation - Restricted Access"],"thesis:degree_name":["Ph. D. in Ceramic Engineering"],"thesis:institution_name":["University of Missouri--Rolla"]},"updated_at":"2026-07-24T03:19:54Z"}