{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/21345"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/21345","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Effect of phase transformations, chemical doping, and matrix constraint on the microstructural development of dicalcium-silicate","abstract":"The factors controlling the monoclinic ($\\beta$) to orthorhombic ($\\gamma$) transformation of dicalcium silicate (Ca$\\sb2$SiO$\\sb4$) at about 490$\\sp\\circ$C have been studied. This transformation is of interest in portland cement technology because the low temperature $\\gamma$ phase is unreactive with water, while the high temperature $\\beta$ phase is. The transformation, which is accompanied by a 12% volume increase and a 4.6$\\sp\\circ$ unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation of ZrO$\\sb2$. Thus Ca$\\sb2$SiO$\\sb4$ is a potential transformation toughener alternative to ZrO$\\sb2$.","abstract_html":"The factors controlling the monoclinic (<span class=\"etd-inline-math\">&beta;</span>) to orthorhombic (<span class=\"etd-inline-math\">&gamma;</span>) transformation of dicalcium silicate (Ca$\\sb2$SiO$\\sb4$) at about 490$\\sp\\circ$C have been studied. This transformation is of interest in portland cement technology because the low temperature <span class=\"etd-inline-math\">&gamma;</span> phase is unreactive with water, while the high temperature <span class=\"etd-inline-math\">&beta;</span> phase is. The transformation, which is accompanied by a 12% volume increase and a 4.6$\\sp\\circ$ unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation of ZrO$\\sb2$. Thus Ca$\\sb2$SiO$\\sb4$ is a potential transformation toughener alternative to ZrO$\\sb2$.","abstract_has_math":true,"creators":["Chan, Chin-Jong"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Engineering","degree_department":null,"school":null,"contributors":["Young, J.F."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:05:59Z","date_published":"2011-05-07T13:05:59Z","updated_at":"2026-07-22T22:25:17Z","subjects":["Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1989 Chan, Chin-Jong"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI8924786","(UMI)AAI8924786"],"render_values":[{"text":"AAI8924786","href":null,"code":true},{"text":"(UMI)AAI8924786","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/21345","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Young, J.F."]},{"key":"dc:creator","label":"Author","values":["Chan, Chin-Jong"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:05:59Z","10000-01-01","1989"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Materials Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1989 Chan, Chin-Jong"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI8924786","(UMI)AAI8924786","http://hdl.handle.net/2142/21345"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The factors controlling the monoclinic ($\\beta$) to orthorhombic ($\\gamma$) transformation of dicalcium silicate (Ca$\\sb2$SiO$\\sb4$) at about 490$\\sp\\circ$C have been studied. This transformation is of interest in portland cement technology because the low temperature $\\gamma$ phase is unreactive with water, while the high temperature $\\beta$ phase is. The transformation, which is accompanied by a 12% volume increase and a 4.6$\\sp\\circ$ unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation of ZrO$\\sb2$. Thus Ca$\\sb2$SiO$\\sb4$ is a potential transformation toughener alternative to ZrO$\\sb2$.","Pure Ca$\\sb2$SiO$\\sb4$ was studied extensively from different aspects. A particle size effect in controlling the transformation was confirmed by low temperature annealing on Ca$\\sb2$SiO$\\sb4$ particles of different sizes. The high temperature $\\beta$ phase was also observed to be stabilized by a low temperature synthesis method or by a laser-melting/roller-quenching technique. Fast quenching through the $\\alpha$ $\\to$ $\\alpha\\sp\\prime\\sb{H}$ transformation was also observed to have a strong effect on the stabilization of $\\beta$ phase at room temperature.","The effects of chemical stabilizers and departures from stoichiometry on the $\\beta$-to-$\\gamma$ transformation were also investigated. Changes in the CaO/SiO$\\sb2$ molar ratio from 1.8 to 2.2 were not able to stabilize the high temperature $\\beta$ phase without concomitant additions of K$\\sb2$O or Al$\\sb2$O$\\sb3$. EPMA and TEM/EDS studies revealed that the dopants tended to concentrate at amorphous grain boundaries. However, higher levels of Al$\\sb2$O$\\sb3$ were also observed to enter the $\\beta$-Ca$\\sb2$SiO$\\sb4$ grains under lime-rich conditions (CaO/SiO$\\sb2$ = 2.2) up to 3.0 wt%. Some additional crystalline phases were observed.","\"Ca$\\sb2$SiO$\\sb4$ was successfully dispersed in a calcium zirconate matrix (CaZrO$\\sb3$; CZ). Dense pellets of CZ-30 vol% Ca$\\sb2$SiO$\\sb4$ were hot-pressed and yielded microstructures of intergranular, irregularly shaped Ca$\\sb2$SiO$\\sb4$ particles. Results suggested that the critical particle size may be determined by overall Ca$\\sb2$SiO$\\sb4$ grain size or twin width and twin length. A characteristic \"\"herring-bone\"\" type or parallel-banded twin structure resulting from fast quenching through the $\\alpha$ $\\to$ $\\alpha\\sp\\prime\\sb{H}$ transformation is believed to modify the $\\beta$ twin length and width. Transformation toughening was proved to be possible. An approximately 5-fold increase in fracture toughness in a CZ-30 vol% Ca$\\sb2$SiO$\\sb4$ composite was observed in a parallel study.\"","Made available in DSpace on 2011-05-07T13:05:59Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 8924786.pdf: 8569009 bytes, checksum: f3a6aa2e67f0bb8ae66773f532073bf1 (MD5) Previous issue date: 1989","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:50:08Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:22:53-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Effect of phase transformations, chemical doping, and matrix constraint on the microstructural development of dicalcium-silicate"]}]}],"canonical_facts":{"dc:contributor":["Young, J.F."],"dc:creator":["Chan, Chin-Jong"],"dc:date":["2011-05-07T13:05:59Z","10000-01-01","1989"],"dc:description":["The factors controlling the monoclinic ($\\beta$) to orthorhombic ($\\gamma$) transformation of dicalcium silicate (Ca$\\sb2$SiO$\\sb4$) at about 490$\\sp\\circ$C have been studied. This transformation is of interest in portland cement technology because the low temperature $\\gamma$ phase is unreactive with water, while the high temperature $\\beta$ phase is. The transformation, which is accompanied by a 12% volume increase and a 4.6$\\sp\\circ$ unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation of ZrO$\\sb2$. Thus Ca$\\sb2$SiO$\\sb4$ is a potential transformation toughener alternative to ZrO$\\sb2$.","Pure Ca$\\sb2$SiO$\\sb4$ was studied extensively from different aspects. A particle size effect in controlling the transformation was confirmed by low temperature annealing on Ca$\\sb2$SiO$\\sb4$ particles of different sizes. The high temperature $\\beta$ phase was also observed to be stabilized by a low temperature synthesis method or by a laser-melting/roller-quenching technique. Fast quenching through the $\\alpha$ $\\to$ $\\alpha\\sp\\prime\\sb{H}$ transformation was also observed to have a strong effect on the stabilization of $\\beta$ phase at room temperature.","The effects of chemical stabilizers and departures from stoichiometry on the $\\beta$-to-$\\gamma$ transformation were also investigated. Changes in the CaO/SiO$\\sb2$ molar ratio from 1.8 to 2.2 were not able to stabilize the high temperature $\\beta$ phase without concomitant additions of K$\\sb2$O or Al$\\sb2$O$\\sb3$. EPMA and TEM/EDS studies revealed that the dopants tended to concentrate at amorphous grain boundaries. However, higher levels of Al$\\sb2$O$\\sb3$ were also observed to enter the $\\beta$-Ca$\\sb2$SiO$\\sb4$ grains under lime-rich conditions (CaO/SiO$\\sb2$ = 2.2) up to 3.0 wt%. Some additional crystalline phases were observed.","\"Ca$\\sb2$SiO$\\sb4$ was successfully dispersed in a calcium zirconate matrix (CaZrO$\\sb3$; CZ). Dense pellets of CZ-30 vol% Ca$\\sb2$SiO$\\sb4$ were hot-pressed and yielded microstructures of intergranular, irregularly shaped Ca$\\sb2$SiO$\\sb4$ particles. Results suggested that the critical particle size may be determined by overall Ca$\\sb2$SiO$\\sb4$ grain size or twin width and twin length. A characteristic \"\"herring-bone\"\" type or parallel-banded twin structure resulting from fast quenching through the $\\alpha$ $\\to$ $\\alpha\\sp\\prime\\sb{H}$ transformation is believed to modify the $\\beta$ twin length and width. Transformation toughening was proved to be possible. An approximately 5-fold increase in fracture toughness in a CZ-30 vol% Ca$\\sb2$SiO$\\sb4$ composite was observed in a parallel study.\"","Made available in DSpace on 2011-05-07T13:05:59Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 8924786.pdf: 8569009 bytes, checksum: f3a6aa2e67f0bb8ae66773f532073bf1 (MD5) Previous issue date: 1989","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:50:08Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:22:53-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI8924786","(UMI)AAI8924786","http://hdl.handle.net/2142/21345"],"dc:language":["eng"],"dc:rights":["Copyright 1989 Chan, Chin-Jong"],"dc:subject":["Engineering, Materials Science"],"dc:title":["Effect of phase transformations, chemical doping, and matrix constraint on the microstructural development of dicalcium-silicate"],"dc:type":["text"],"thesis:degree_discipline":["Materials Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:17Z"}