{"id":{"repo_id":"must-thes","oai_identifier":"oai:scholarsmine.mst.edu:doctoral_dissertations-2979"},"canonical_url":"https://search.dev.ndltd.org/etd/must-thes/oai:scholarsmine.mst.edu:doctoral_dissertations-2979","repository":{"repo_id":"must-thes","name":"Missouri University of Science and Technology","base_url":"https://scholarsmine.mst.edu/do/oai/"},"display":{"title":"Decomposition of Cr(OH)₃ to form active Cr₂C₃","abstract":"\"This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per mole were found for the decomposition process and the crystallite growth process, respectively. The decomposition process can be described as a unimolecular mechanism obeying first-order reaction kinetics. The calcined powders were found to be composed of small hexagonal platelets arranged in loosely packed aggregates. The optimum calcination temperature was determined to be approximately 500⁰C. A maximum sintered density of 4.35 grams per cubic centimeter illustrated the effectiveness of a nitrogen sintering atmosphere\"--Abstract, page ii-iii.","abstract_html":""This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per mole were found for the decomposition process and the crystallite growth process, respectively. The decomposition process can be described as a unimolecular mechanism obeying first-order reaction kinetics. The calcined powders were found to be composed of small hexagonal platelets arranged in loosely packed aggregates. The optimum calcination temperature was determined to be approximately 500⁰C. A maximum sintered density of 4.35 grams per cubic centimeter illustrated the effectiveness of a nitrogen sintering atmosphere"--Abstract, page ii-iii.","abstract_has_math":false,"creators":["Clancy, Timothy A."],"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":"2026-07-24T03:19:30Z","subjects":["Ceramic Materials"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/1977","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Clancy, Timothy A."]}]},{"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 - Open 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/1977"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["\"This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per mole were found for the decomposition process and the crystallite growth process, respectively. The decomposition process can be described as a unimolecular mechanism obeying first-order reaction kinetics. The calcined powders were found to be composed of small hexagonal platelets arranged in loosely packed aggregates. The optimum calcination temperature was determined to be approximately 500⁰C. A maximum sintered density of 4.35 grams per cubic centimeter illustrated the effectiveness of a nitrogen sintering atmosphere\"--Abstract, page ii-iii."]},{"key":"dc:title","label":"Title","values":["Decomposition of Cr(OH)₃ to form active Cr₂C₃"]}]}],"canonical_facts":{"dc:creator":["Clancy, Timothy A."],"dc:date.available":["2016-02-10T08:00:00Z"],"dc:description.abstract":["\"This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per mole were found for the decomposition process and the crystallite growth process, respectively. The decomposition process can be described as a unimolecular mechanism obeying first-order reaction kinetics. The calcined powders were found to be composed of small hexagonal platelets arranged in loosely packed aggregates. The optimum calcination temperature was determined to be approximately 500⁰C. A maximum sintered density of 4.35 grams per cubic centimeter illustrated the effectiveness of a nitrogen sintering atmosphere\"--Abstract, page ii-iii."],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/1977"],"dc:subject":["Ceramic Materials"],"dc:title":["Decomposition of Cr(OH)₃ to form active Cr₂C₃"],"dc:type":["Dissertation - Open Access"],"thesis:degree_name":["Ph. D. in Ceramic Engineering"],"thesis:institution_name":["University of Missouri--Rolla"]},"updated_at":"2026-07-24T03:19:30Z"}