Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90021-8
O. Hunter, R. Scheidecker, S. Tojo
{"title":"Characterization of metastable tetragonal hafnia","authors":"O. Hunter, R. Scheidecker, S. Tojo","doi":"10.1016/0390-5519(79)90021-8","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90021-8","url":null,"abstract":"","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"17 1","pages":"137-142"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75691270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90020-6
T. Mitamura, E. Hall, W. Kingery, J. B. Sande
{"title":"Grain boundary segregation of iron in polycrystalline magnesium oxide observed by STEM","authors":"T. Mitamura, E. Hall, W. Kingery, J. B. Sande","doi":"10.1016/0390-5519(79)90020-6","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90020-6","url":null,"abstract":"","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"58 1","pages":"131-136"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84450628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90021-8
O. Hunter Jr., R.W. Scheidecker, Setsuo Tojo
Conditions for retaining metastable tetragonal HfO2 at room temperature were determined. Mechanical properties were measured as a function both of the fraction of retained metastable HfO2 and of the porosity. The metastable phase was retained by 1) thermal decomposition of pure Hf(OH)4 or HfOCl2 and 2) hot pressing of HfO2 + 1% Er2O3. The critical size for retaining pure tetragonal HfO2 at room temperature in a stress free condition is 100 Å, whereas the critical size for the 1% Er2O3 hot pressed composition is significantly larger. The elastic moduli were found to vary linearly with porosity and showed a small effect due to the metastable phase presence.
{"title":"Characterization of metastable tetragonal hafnia","authors":"O. Hunter Jr., R.W. Scheidecker, Setsuo Tojo","doi":"10.1016/0390-5519(79)90021-8","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90021-8","url":null,"abstract":"<div><p>Conditions for retaining metastable tetragonal HfO<sub>2</sub> at room temperature were determined. Mechanical properties were measured as a function both of the fraction of retained metastable HfO<sub>2</sub> and of the porosity. The metastable phase was retained by 1) thermal decomposition of pure Hf(OH)<sub>4</sub> or HfOCl<sub>2</sub> and 2) hot pressing of HfO<sub>2</sub> + 1% Er<sub>2</sub>O<sub>3</sub>. The critical size for retaining pure tetragonal HfO<sub>2</sub> at room temperature in a stress free condition is 100 Å, whereas the critical size for the 1% Er<sub>2</sub>O<sub>3</sub> hot pressed composition is significantly larger. The elastic moduli were found to vary linearly with porosity and showed a small effect due to the metastable phase presence.</p></div>","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"5 4","pages":"Pages 137-142"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-5519(79)90021-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91654882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90020-6
T. Mitamura, E.L. Hall, W.D. Kingery, J.B. Vander Sande
Utilizing X-ray microanalysis in samples studied with scanning transmission electron microscopy, substantial grain boundary segregation of Fe is found in grain boundaries in polycrystalline MgO. Samples studied contained between 540 and 5400 cation ppm Fe. Grain boundary segregation in the region within 200 Å of the boundary was found in all cases, with the amount of segregation increasing with increasing Fe content. Samples slow-cooled from 1500°C showed an increased amount of segregation attributed to continued diffusion during cooling. Samples quenched from 1100°C showed greater segregation than those quenched from 1500°C, consistent with space charge theory. In some samples precipitates were observed which are correlated with a low-temperature phase diagram for the solidus in the iron oxide-magnesium oxide system. In addition to Fe, grain boundary segregation of Ca and Si impurities in the samples was also observed.
{"title":"Grain boundary segregation of iron in polycrystalline magnesium oxide observed by STEM","authors":"T. Mitamura, E.L. Hall, W.D. Kingery, J.B. Vander Sande","doi":"10.1016/0390-5519(79)90020-6","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90020-6","url":null,"abstract":"<div><p>Utilizing X-ray microanalysis in samples studied with scanning transmission electron microscopy, substantial grain boundary segregation of Fe is found in grain boundaries in polycrystalline MgO. Samples studied contained between 540 and 5400 cation ppm Fe. Grain boundary segregation in the region within 200 Å of the boundary was found in all cases, with the amount of segregation increasing with increasing Fe content. Samples slow-cooled from 1500°C showed an increased amount of segregation attributed to continued diffusion during cooling. Samples quenched from 1100°C showed greater segregation than those quenched from 1500°C, consistent with space charge theory. In some samples precipitates were observed which are correlated with a low-temperature phase diagram for the solidus in the iron oxide-magnesium oxide system. In addition to Fe, grain boundary segregation of Ca and Si impurities in the samples was also observed.</p></div>","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"5 4","pages":"Pages 131-136"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-5519(79)90020-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91609538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90025-5
G. Bagnasco, P. Pernice, P. Orsini
{"title":"The corrosion of tin oxide semiconducting glazes","authors":"G. Bagnasco, P. Pernice, P. Orsini","doi":"10.1016/0390-5519(79)90025-5","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90025-5","url":null,"abstract":"","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"46 1","pages":"161-164"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85999533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90022-X
K. Keizer, M. Verkerk, A. Burggraaf
{"title":"Preparation and properties of new oxygen ion conductors for use at low temperatures","authors":"K. Keizer, M. Verkerk, A. Burggraaf","doi":"10.1016/0390-5519(79)90022-X","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90022-X","url":null,"abstract":"","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"11 1","pages":"143-147"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88601809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90022-X
K. Keizer, M.J. Verkerk, A.J. Burggraaf
Two new systems, Bi2O3Er2O3 and ZrO2Y2O3(CaO)Bi2O3 were investigated. The first system has a homogeneous cubic, fluorite phase between 17.5 and 45.5 mol % Er2O3 and can be sintered to densities near 95% at 1200 K. At temperatures between 700 K and 1000 K the highest value of the a.c. oxygen ion conduction in this system is twice as much as the highest value found in the literature. In the second system concentrations of 1–3 mol % Bi2O3 act as an excellent sintering aid for ZrO2Y2O3 and ZrO2CaO samples which can be sintered to densities higher than 95% at temperatures of 1350 K. During this procedure a liquid ZrO2Bi2O3 phase exists from which Bi2O3 partly evaporates with increasing sintering time. The oxygen ion conduction is little affected by the Bi2O3-rich second phase. The influence of annealing procedures up to 1570 K on the conduction in the ZrO2Y2O3Bi2O3 system is small despite weight losses up to 4%.
{"title":"Preparation and properties of new oxygen ion conductors for use at low temperatures","authors":"K. Keizer, M.J. Verkerk, A.J. Burggraaf","doi":"10.1016/0390-5519(79)90022-X","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90022-X","url":null,"abstract":"<div><p>Two new systems, Bi<sub>2</sub>O<sub>3</sub>Er<sub>2</sub>O<sub>3</sub> and ZrO<sub>2</sub>Y<sub>2</sub>O<sub>3</sub>(CaO)Bi<sub>2</sub>O<sub>3</sub> were investigated. The first system has a homogeneous cubic, fluorite phase between 17.5 and 45.5 mol % Er<sub>2</sub>O<sub>3</sub> and can be sintered to densities near 95% at 1200 K. At temperatures between 700 K and 1000 K the highest value of the a.c. oxygen ion conduction in this system is twice as much as the highest value found in the literature. In the second system concentrations of 1–3 mol % Bi<sub>2</sub>O<sub>3</sub> act as an excellent sintering aid for ZrO<sub>2</sub>Y<sub>2</sub>O<sub>3</sub> and ZrO<sub>2</sub>CaO samples which can be sintered to densities higher than 95% at temperatures of 1350 K. During this procedure a liquid ZrO<sub>2</sub>Bi<sub>2</sub>O<sub>3</sub> phase exists from which Bi<sub>2</sub>O<sub>3</sub> partly evaporates with increasing sintering time. The oxygen ion conduction is little affected by the Bi<sub>2</sub>O<sub>3</sub>-rich second phase. The influence of annealing procedures up to 1570 K on the conduction in the ZrO<sub>2</sub>Y<sub>2</sub>O<sub>3</sub>Bi<sub>2</sub>O<sub>3</sub> system is small despite weight losses up to 4%.</p></div>","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"5 4","pages":"Pages 143-147"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-5519(79)90022-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91609537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1979-10-01DOI: 10.1016/0390-5519(79)90025-5
G. Bagnasco, P. Pernice, P.Giordano Orsini
An SnO2Sb2O5 glaze, which seems the most promising among semiconducting porcelain glazes for high voltage applications, has been operated as electrode in Na2SO4 solution, to study under controlled conditions, its corrosion behaviour. The morphology of the corrosion has been observed by microscopy. Metallic tin produced by electrochemical reduction has been identified by X-ray diffraction.
{"title":"The corrosion of tin oxide semiconducting glazes","authors":"G. Bagnasco, P. Pernice, P.Giordano Orsini","doi":"10.1016/0390-5519(79)90025-5","DOIUrl":"https://doi.org/10.1016/0390-5519(79)90025-5","url":null,"abstract":"<div><p>An SnO<sub>2</sub>Sb<sub>2</sub>O<sub>5</sub> glaze, which seems the most promising among semiconducting porcelain glazes for high voltage applications, has been operated as electrode in Na<sub>2</sub>SO<sub>4</sub> solution, to study under controlled conditions, its corrosion behaviour. The morphology of the corrosion has been observed by microscopy. Metallic tin produced by electrochemical reduction has been identified by X-ray diffraction.</p></div>","PeriodicalId":100227,"journal":{"name":"Ceramurgia International","volume":"5 4","pages":"Pages 161-164"},"PeriodicalIF":0.0,"publicationDate":"1979-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-5519(79)90025-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91597508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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