Pub Date : 2024-11-01DOI: 10.1016/j.bsecv.2024.09.002
Carlos Gumiel , María Colado , David G. Calatayud , Rafael Barea , Marina Villegas , Teresa Jardiel
A microstructure based on plate-like grains is expected in the obtaining of Bi4Ti3O12 ferroelectric ceramics, promoted by the Aurivillius crystalline structure that this material exhibit. This grain morphology would lead to conductivity making the functional response unpractical. In this frame, we address the control of the crystal growth which leads to this grain morphology by combining the effect of a simple thin film obtaining procedure with doping strategies. On the one hand, an aqueous solution-gel plus spin-coating methodology is performed here for the obtaining of these thin films. On the other hand, a simultaneous incorporation of Nd3+ and Nb5+ in the crystal lattice replacing Bi3+ and Ti4+, respectively, is conducted in this contribution. The results obtained by X-ray diffraction, UV–visible measurements and FESEM confirm that the incorporated dopants are able to block (or at least control) the mentioned crystal growth.
{"title":"Microstructure modulation of a Bi4Ti3O12 thin film system by combining the effect of a simple processing methodology with a co-doping strategy involving Nd3+ and Nb5+","authors":"Carlos Gumiel , María Colado , David G. Calatayud , Rafael Barea , Marina Villegas , Teresa Jardiel","doi":"10.1016/j.bsecv.2024.09.002","DOIUrl":"10.1016/j.bsecv.2024.09.002","url":null,"abstract":"<div><div>A microstructure based on plate-like grains is expected in the obtaining of Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> ferroelectric ceramics, promoted by the Aurivillius crystalline structure that this material exhibit. This grain morphology would lead to conductivity making the functional response unpractical. In this frame, we address the control of the crystal growth which leads to this grain morphology by combining the effect of a simple thin film obtaining procedure with doping strategies. On the one hand, an aqueous solution-gel plus spin-coating methodology is performed here for the obtaining of these thin films. On the other hand, a simultaneous incorporation of Nd<sup>3+</sup> and Nb<sup>5+</sup> in the crystal lattice replacing Bi<sup>3+</sup> and Ti<sup>4+</sup>, respectively, is conducted in this contribution. The results obtained by X-ray diffraction, UV–visible measurements and FESEM confirm that the incorporated dopants are able to block (or at least control) the mentioned crystal growth.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 6","pages":"Pages 425-433"},"PeriodicalIF":2.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.bsecv.2024.06.004
Willams Teles Barbosa , Imarally Vitor de Souza Ribeiro Nascimento , Daniel Bezerra Lima , Francivandi Coelho Barbosa , Benjamin S. Lazarus , Josiane Dantas Viana Barbosa , Marcus Vinicius Lia Fook , Raúl Garcia Carrodeguas , Miguel Ángel Rodriguez
Aluminate-based endodontic cements are promising in root canal treatments. Calcium aluminates have been used as bone and dental fillers, due to their fast setting time, good workability, and biocompatibility, overcoming some of the disadvantages of mineral trioxide aggregate (MTA) currently available. Similarly, strontium aluminates are of interest, due to their potential as hydraulic cement. They have greater radiopacity than their calcium counterparts and the potential to promote osteoblast differentiation which favors bone regeneration. The present study evaluates the in vitro biological properties of the new endodontic cement CS5C (80/20 wt.% of S3A (tri-strontium aluminate (Sr3Al2O6)) and C12A7 (dodeca-calcium hepta-aluminate (Ca12Al14O33))). The in vitro ion release tests showed that Al3+, Ca2+, and Sr2+ ions are responsible for the alkaline pH of the medium, promoting antimicrobial activity against all bacterial strains tested. It also showed biocompatible properties, with promising cellular adhesion and proliferation in vitro. The results revealed that CS5S cement has strong potential for future applications as endodontic cement.
{"title":"In vitro evaluation of a new endodontic cement based on calcium and strontium aluminate","authors":"Willams Teles Barbosa , Imarally Vitor de Souza Ribeiro Nascimento , Daniel Bezerra Lima , Francivandi Coelho Barbosa , Benjamin S. Lazarus , Josiane Dantas Viana Barbosa , Marcus Vinicius Lia Fook , Raúl Garcia Carrodeguas , Miguel Ángel Rodriguez","doi":"10.1016/j.bsecv.2024.06.004","DOIUrl":"10.1016/j.bsecv.2024.06.004","url":null,"abstract":"<div><div>Aluminate-based endodontic cements are promising in root canal treatments. Calcium aluminates have been used as bone and dental fillers, due to their fast setting time, good workability, and biocompatibility, overcoming some of the disadvantages of mineral trioxide aggregate (MTA) currently available. Similarly, strontium aluminates are of interest, due to their potential as hydraulic cement. They have greater radiopacity than their calcium counterparts and the potential to promote osteoblast differentiation which favors bone regeneration. The present study evaluates the <em>in vitro</em> biological properties of the new endodontic cement CS5C (80/20<!--> <!-->wt.% of S<sub>3</sub>A (tri-strontium aluminate (Sr<sub>3</sub>Al<sub>2</sub>O<sub>6</sub>)) and C<sub>12</sub>A<sub>7</sub> (dodeca-calcium hepta-aluminate (Ca<sub>12</sub>Al<sub>14</sub>O<sub>33</sub>))). The <em>in vitro</em> ion release tests showed that Al<sup>3+</sup>, Ca<sup>2+</sup>, and Sr<sup>2+</sup> ions are responsible for the alkaline pH of the medium, promoting antimicrobial activity against all bacterial strains tested. It also showed biocompatible properties, with promising cellular adhesion and proliferation <em>in vitro</em>. The results revealed that CS5S cement has strong potential for future applications as endodontic cement.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 6","pages":"Pages 390-397"},"PeriodicalIF":2.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141689960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the characterization of two clays obtained from the Safi and Fez regions, focusing on their analysis for filtration membrane applications. Various analytical techniques were employed, including chemical composition analysis, elemental analysis, mineralogical characterization, carbonate content determination, color assessment, plasticity evaluation, thermal treatment analysis (DTA-TG), mineralogical transformation study, fusion tests, membrane tests, and scanning electron microscopy (SEM).
The results reveal significant differences between the two clays regarding their chemical composition. The red clay exhibits a mineralogical composition comprising quartz, calcite, dolomite, hematite, illite, and kaolinite, whereas the gray clay contains quartz, calcite, dolomite, illite, talc, and montmorillonite. Furthermore, upon thermal treatment, both clays exhibit changes in their physical properties.
Despite the decrease in porosity and water absorption, as well as the increase in compression strength for both clays, the permeability of the grey clay increases, unlike the red clay, which exhibits a constant permeability beyond 1000 °C.
These findings highlight the diversity and industrial significance of clays from the Safi and Fez regions for filtration membrane applications. The contrasting properties of red and gray clays provide insights into their potential utilization in different industries. Exploring these clays’ behavior can lead to better filtration membranes and new industrial applications.
本研究调查了从萨菲和非斯地区获得的两种粘土的特性,重点分析了它们在过滤膜应用方面的特性。研究采用了多种分析技术,包括化学成分分析、元素分析、矿物学表征、碳酸盐含量测定、颜色评估、可塑性评估、热处理分析(DTA-TG)、矿物学转化研究、熔融试验、膜试验和扫描电子显微镜(SEM)。红色粘土的矿物成分包括石英、方解石、白云石、赤铁矿、伊利石和高岭石,而灰色粘土则含有石英、方解石、白云石、伊利石、滑石和蒙脱石。此外,经过热处理后,两种粘土的物理性质都发生了变化。尽管两种粘土的孔隙率和吸水率都有所下降,压缩强度也有所提高,但灰色粘土的渗透性却增加了,这与红粘土不同,后者的渗透性在 1000 °C 以上保持不变。红粘土和灰粘土截然不同的特性为它们在不同行业的潜在应用提供了启示。对这些粘土行为的探索将带来更好的过滤膜和新的工业应用。
{"title":"Exploring the diversity of clays: Impacts of temperature on physicochemical changes, mechanical characteristics, and permeability, and their relevance to membrane applications","authors":"Khadija Elataoui , Mohamed Amine Harech , Hajar Qobay , Noureddine Elbinna , Hakima Aouad , Mohamed Waqif , Latifa Saadi","doi":"10.1016/j.bsecv.2024.07.001","DOIUrl":"10.1016/j.bsecv.2024.07.001","url":null,"abstract":"<div><div>This study investigates the characterization of two clays obtained from the Safi and Fez regions, focusing on their analysis for filtration membrane applications. Various analytical techniques were employed, including chemical composition analysis, elemental analysis, mineralogical characterization, carbonate content determination, color assessment, plasticity evaluation, thermal treatment analysis (DTA-TG), mineralogical transformation study, fusion tests, membrane tests, and scanning electron microscopy (SEM).</div><div>The results reveal significant differences between the two clays regarding their chemical composition. The red clay exhibits a mineralogical composition comprising quartz, calcite, dolomite, hematite, illite, and kaolinite, whereas the gray clay contains quartz, calcite, dolomite, illite, talc, and montmorillonite. Furthermore, upon thermal treatment, both clays exhibit changes in their physical properties.</div><div>Despite the decrease in porosity and water absorption, as well as the increase in compression strength for both clays, the permeability of the grey clay increases, unlike the red clay, which exhibits a constant permeability beyond 1000<!--> <!-->°C.</div><div>These findings highlight the diversity and industrial significance of clays from the Safi and Fez regions for filtration membrane applications. The contrasting properties of red and gray clays provide insights into their potential utilization in different industries. Exploring these clays’ behavior can lead to better filtration membranes and new industrial applications.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 6","pages":"Pages 398-412"},"PeriodicalIF":2.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.bsecv.2024.09.005
Ana Castellanos-Aliaga , Laura San-Miguel , Marina Villegas , Ángel Caballero , Marco Peiteado , David González Calatayud
In the process of photocatalytic degradation of plastics, the surface interaction between the plastic material and the photocatalyst results crucial. The present work focuses on using a specific TiO2 photocatalytic semiconductor whose hierarchical structure favours the interaction with low density polyethylene (LDPE), a key component in plastics. An exhaustive study of the nature of this interaction is conducted, analysing the influence of the atmosphere and radiation. The results obtained indicate that the observed interaction can be modulated by controlling the atmosphere, evolving into a degradation process whose mechanism also depends on the absence or the presence of light. This point is particularly relevant as it highlights the dual nature of TiO2 as both photocatalyst and catalyst.
{"title":"Study of the interaction between low density polyethylene and TiO2 in different environments. Influence of the presence and absence of radiation, and of the atmosphere (O2, N2 or Ar)","authors":"Ana Castellanos-Aliaga , Laura San-Miguel , Marina Villegas , Ángel Caballero , Marco Peiteado , David González Calatayud","doi":"10.1016/j.bsecv.2024.09.005","DOIUrl":"10.1016/j.bsecv.2024.09.005","url":null,"abstract":"<div><div>In the process of photocatalytic degradation of plastics, the surface interaction between the plastic material and the photocatalyst results crucial. The present work focuses on using a specific TiO<sub>2</sub> photocatalytic semiconductor whose hierarchical structure favours the interaction with low density polyethylene (LDPE), a key component in plastics. An exhaustive study of the nature of this interaction is conducted, analysing the influence of the atmosphere and radiation. The results obtained indicate that the observed interaction can be modulated by controlling the atmosphere, evolving into a degradation process whose mechanism also depends on the absence or the presence of light. This point is particularly relevant as it highlights the dual nature of TiO<sub>2</sub> as both photocatalyst and catalyst.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 6","pages":"Pages 434-445"},"PeriodicalIF":2.7,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.bsecv.2024.06.003
Mario Flores Nicolás , Marcos M. Chávez , Marina Vlasova , Teresa Pi Puig
In the present work, bricks were made on a real 1:1 scale for the construction of housing. For the preparation of the mixtures, raw materials such as clay, sand and glass obtained from the recycling of brown beer containers were used, applying the method plastic molding for the preparation of the semi-products. It has been established that the addition of sand containing a small amount of montmorillonite to such clay enabled to realization of plastic molding. The incorporation of glass into the clay provided to substantially reduce the sintering time of the bricks up to 8 h and to vary their strength properties. Sintering was carried out at 800 °C in an air atmosphere. The results of X-ray diffraction (XRD), X-ray fluorescence (XRF) and field emission scanning electron microscopy (FESEM) and EDS microanalysis have shown that the raw materials and ceramic bricks contains quartz and feldspars. Low-temperature sintering has made it possible to obtain high-quality, high-strength building bricks in accordance with standards.
{"title":"Low-temperature sintering of ceramic bricks from clay, waste glass and sand","authors":"Mario Flores Nicolás , Marcos M. Chávez , Marina Vlasova , Teresa Pi Puig","doi":"10.1016/j.bsecv.2024.06.003","DOIUrl":"10.1016/j.bsecv.2024.06.003","url":null,"abstract":"<div><div>In the present work, bricks were made on a real 1:1 scale for the construction of housing. For the preparation of the mixtures, raw materials such as clay, sand and glass obtained from the recycling of brown beer containers were used, applying the method plastic molding for the preparation of the semi-products. It has been established that the addition of sand containing a small amount of montmorillonite to such clay enabled to realization of plastic molding. The incorporation of glass into the clay provided to substantially reduce the sintering time of the bricks up to 8<!--> <!-->h and to vary their strength properties. Sintering was carried out at 800<!--> <!-->°C in an air atmosphere. The results of X-ray diffraction (XRD), X-ray fluorescence (XRF) and field emission scanning electron microscopy (FESEM) and EDS microanalysis have shown that the raw materials and ceramic bricks contains quartz and feldspars. Low-temperature sintering has made it possible to obtain high-quality, high-strength building bricks in accordance with standards.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 5","pages":"Pages 377-388"},"PeriodicalIF":2.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.bsecv.2024.05.002
The conflict in Ukraine has meant that the supply of ball clay from this country has been cut off, giving rise to a serious setback for the manufacture of porcelain tile, as this raw material was a basic component for the formulation of this type of ceramic tile. This work proposes the use of a clay from the Afyon area in Turkey as an alternative, which is formed by a complex mixture of clay and non-clay minerals.
In the first part of the study, a complete characterisation of the clay has been carried out, comparing it with a standard Ukrainian clay. In a second part, a composition in which Afyon clay is the main clay component has been formulated and characterised in comparison with a standard composition formulated with Ukrainian clays. Overall, the results show that, although some properties for Afyon clay differ from those for Ukrainian clays, the behaviour of the proposed composition in the different stages of the process, milling/deflocculation, pressing and firing, is similar to that of the standard composition, thus adapting it to the requirements of industrial practice. This provides a feasible alternative way of replacing Ukrainian ball clays.
{"title":"On the use of Afyon clay in Ukrainian clay-free compositions for porcelain tile manufacture","authors":"","doi":"10.1016/j.bsecv.2024.05.002","DOIUrl":"10.1016/j.bsecv.2024.05.002","url":null,"abstract":"<div><div>The conflict in Ukraine has meant that the supply of ball clay from this country has been cut off, giving rise to a serious setback for the manufacture of porcelain tile, as this raw material was a basic component for the formulation of this type of ceramic tile. This work proposes the use of a clay from the Afyon area in Turkey as an alternative, which is formed by a complex mixture of clay and non-clay minerals.</div><div>In the first part of the study, a complete characterisation of the clay has been carried out, comparing it with a standard Ukrainian clay. In a second part, a composition in which Afyon clay is the main clay component has been formulated and characterised in comparison with a standard composition formulated with Ukrainian clays. Overall, the results show that, although some properties for Afyon clay differ from those for Ukrainian clays, the behaviour of the proposed composition in the different stages of the process, milling/deflocculation, pressing and firing, is similar to that of the standard composition, thus adapting it to the requirements of industrial practice. This provides a feasible alternative way of replacing Ukrainian ball clays.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 5","pages":"Pages 356-367"},"PeriodicalIF":2.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141391976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.bsecv.2024.05.001
Jon García-Barruetabeña, David Miñón, Beatriz Achiaga, Fernando Cortés
This article presents a methodology for the characterization of the dynamic properties of a laminated glass automotive ceiling, motivated by the inherent difficulty in obtaining laboratory samples from this kind of components. This methodology is based on the identification of the effective complex modulus of the laminated glass ceiling through Experimental Modal Analysis in conjunction with a finite element model. Besides, a material behaviour model is proposed for the effective complex module. Then, the dynamic properties of the laminated glass core are extracted from the latter using a reverse homogenized formulation of sandwich plates specifically developed in this work. As a result, a methodology to accurately predict the dynamic behaviour of these key automotive components has been achieved. An additional advantage of this methodology is that the identification of properties is carried out from a manufactured component and not from samples of reduced geometries, considering the impact of the manufacturing process.
{"title":"Characterization of the dynamic properties of an automotive laminated glass ceiling","authors":"Jon García-Barruetabeña, David Miñón, Beatriz Achiaga, Fernando Cortés","doi":"10.1016/j.bsecv.2024.05.001","DOIUrl":"10.1016/j.bsecv.2024.05.001","url":null,"abstract":"<div><div>This article presents a methodology for the characterization of the dynamic properties of a laminated glass automotive ceiling, motivated by the inherent difficulty in obtaining laboratory samples from this kind of components. This methodology is based on the identification of the effective complex modulus of the laminated glass ceiling through Experimental Modal Analysis in conjunction with a finite element model. Besides, a material behaviour model is proposed for the effective complex module. Then, the dynamic properties of the laminated glass core are extracted from the latter using a reverse homogenized formulation of sandwich plates specifically developed in this work. As a result, a methodology to accurately predict the dynamic behaviour of these key automotive components has been achieved. An additional advantage of this methodology is that the identification of properties is carried out from a manufactured component and not from samples of reduced geometries, considering the impact of the manufacturing process.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 5","pages":"Pages 346-355"},"PeriodicalIF":2.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.bsecv.2024.06.002
Daniel Drdlik , Vojtech Marak , Robert Klement , Pavel Tofel , Katarina Drdlikova , Hynek Hadraba , Zdenek Chlup
In progressive particle or layered composites based on a combination of BaTiO3 and Al2O3, serving as e.g. ceramic harvesters, new phases are formed during heat treatment. The dominant one is BaTiAl6O12. This study provides information about the microstructural, mechanical and optical properties of the BaTiAl6O12 ceramics. The evolution of the phases during the solid-state reaction synthesis of the BaTiAl6O12 was monitored. The fully dense samples prepared by spark plasma sintering had indentation Vickers hardness and indentation elastic modulus within ranges of 10.1–13.7 GPa and 132.0–187.0 GPa, depending on loading force. The three-point bending tests of the BaTiAl6O12 samples resulted in flexural strength of 129.9 MPa and fracture toughness of 1.8 MPa m1/2. The sample showed blue broad-band emission under UV excitation due to the charge-transfer transition of the Ti4+ and defect sites. The BaTiAl6O12 evinced low permittivity (ɛ′) = 16 and dielectric loss (tanδ) <0.0003 at a frequency 1 kHz.
{"title":"Basic microstructural, mechanical, electrical and optical characterisation of BaTiAl6O12 ceramics","authors":"Daniel Drdlik , Vojtech Marak , Robert Klement , Pavel Tofel , Katarina Drdlikova , Hynek Hadraba , Zdenek Chlup","doi":"10.1016/j.bsecv.2024.06.002","DOIUrl":"10.1016/j.bsecv.2024.06.002","url":null,"abstract":"<div><div>In progressive particle or layered composites based on a combination of BaTiO<sub>3</sub> and Al<sub>2</sub>O<sub>3</sub>, serving as e.g. ceramic harvesters, new phases are formed during heat treatment. The dominant one is BaTiAl<sub>6</sub>O<sub>12</sub>. This study provides information about the microstructural, mechanical and optical properties of the BaTiAl<sub>6</sub>O<sub>12</sub> ceramics. The evolution of the phases during the solid-state reaction synthesis of the BaTiAl<sub>6</sub>O<sub>12</sub> was monitored. The fully dense samples prepared by spark plasma sintering had indentation Vickers hardness and indentation elastic modulus within ranges of 10.1–13.7<!--> <!-->GPa and 132.0–187.0<!--> <!-->GPa, depending on loading force. The three-point bending tests of the BaTiAl<sub>6</sub>O<sub>12</sub> samples resulted in flexural strength of 129.9<!--> <!-->MPa and fracture toughness of 1.8<!--> <!-->MPa<!--> <!-->m<sup>1/2</sup>. The sample showed blue broad-band emission under UV excitation due to the charge-transfer transition of the Ti<sup>4+</sup> and defect sites. The BaTiAl<sub>6</sub>O<sub>12</sub> evinced low permittivity (<em>ɛ</em>′)<!--> <!-->=<!--> <!-->16 and dielectric loss (<em>tan</em> <em>δ</em>) <0.0003 at a frequency 1<!--> <!-->kHz.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 5","pages":"Pages 368-376"},"PeriodicalIF":2.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.bsecv.2024.07.002
María Luisa Sanjuán , Rosa Isabel Merino , Annu Kumar Lakshya , Anirban Chowdhury
Ceria-based compounds with trivalent dopant ions are currently being investigated as electrolytes for solid oxide fuel cells operating at low to intermediate temperatures. In these materials, the dependence of the ionic conductivity on the dopant content, the relative cation size and the dopant/vacancy or vacancy/vacancy interactions are the subject of intense research, but there is scarce information about a possible correlation between these properties and microstructural ones, such as texture. Here, we address this question in the heavily doped fluorite-like La2Ce2O7 oxide, using a combination of X-ray diffraction, electron microscopy, optical absorption, Raman scattering and impedance spectroscopy. In all cases, materials with varying degree of 〈1 1 1〉 texture are compared with untextured samples. In this context, the most relevant Raman signatures are the fluorite-like mode at ∼448 cm−1 and a vacancy-related band at ∼578 cm−1. Although remarkable changes were observed upon varying the sintering temperature or the excitation wavelength, both textured and untextured materials displayed similar evolution. A selective enhancement of the vacancy-related band was observed upon decreasing the excitation wavelength from 647 to 488 nm, which is attributed to a resonance phenomenon involving vacancy-related electronic transitions. An indication of incipient vacancy ordering was given by the observation of an intense band at ∼346 cm−1, denoting C-R2O3-like short-range order; its enhancement with the annealing temperature is attributed to the growth of the C-like regions. Conductivity was measured in textured and untextured, fully dense pellets, in the former along and across the texture direction. Impedance plots suggest that the conductivity is dominated by oxide ions and do not allow to separate a grain boundary contribution in these materials with grain size around 1–2 μm. The conductivity amounts to around 10−5 S/cm at 650 K, with activation energy of 1.08–1.16 eV in the temperature range from around 470 to 870 K. Results were similar in textured and untextured materials. We conclude that there is no significant correlation between texture and vacancy concentration or vacancy ordering. A similar conclusion – no influence of texture – is reached concerning the electrical properties.
目前正在研究将含有三价掺杂离子的铈基化合物作为在中低温下工作的固体氧化物燃料电池的电解质。在这些材料中,离子电导率与掺杂剂含量、相对阳离子尺寸和掺杂剂/空位或空位/空位相互作用的关系是研究的热点,但有关这些特性与微观结构特性(如质地)之间可能存在的相关性的信息却很少。在此,我们结合使用 X 射线衍射、电子显微镜、光学吸收、拉曼散射和阻抗光谱,在重掺杂萤石类 La2Ce2O7 氧化物中解决了这一问题。在所有情况下,具有不同程度〈1 1 1〉纹理的材料都与无纹理样品进行了比较。在这种情况下,最相关的拉曼特征是 ∼448 cm-1 处的萤石样模式和 ∼578 cm-1 处的空位相关带。尽管在改变烧结温度或激发波长时观察到了明显的变化,但有纹理和无纹理材料都显示出类似的演变。当激发波长从 647 纳米降低到 488 纳米时,观察到空位相关带有选择性地增强,这归因于涉及空位相关电子跃迁的共振现象。在 ∼346 cm-1 处观察到一个强烈的条带,表示类似 C-R2O3 的短程有序,这表明了空位有序化的萌芽;它随退火温度的升高而增强,这归因于类似 C 区域的增长。在有纹理和无纹理、完全致密的颗粒中测量了前者沿纹理方向和跨纹理方向的电导率。阻抗图显示,导电性主要由氧化物离子主导,无法从这些晶粒尺寸约为 1-2 μm 的材料中分离出晶界的贡献。在 650 K 时,电导率约为 10-5 S/cm,在约 470 至 870 K 的温度范围内,活化能为 1.08-1.16 eV。我们得出结论:质地与空位浓度或空位排序之间没有明显的相关性。在电学特性方面,我们也得出了类似的结论--质地没有影响。
{"title":"Spectroscopic insight into the structural and microstructural properties of La2Ce2O7 ceramics","authors":"María Luisa Sanjuán , Rosa Isabel Merino , Annu Kumar Lakshya , Anirban Chowdhury","doi":"10.1016/j.bsecv.2024.07.002","DOIUrl":"10.1016/j.bsecv.2024.07.002","url":null,"abstract":"<div><div>Ceria-based compounds with trivalent dopant ions are currently being investigated as electrolytes for solid oxide fuel cells operating at low to intermediate temperatures. In these materials, the dependence of the ionic conductivity on the dopant content, the relative cation size and the dopant/vacancy or vacancy/vacancy interactions are the subject of intense research, but there is scarce information about a possible correlation between these properties and microstructural ones, such as texture. Here, we address this question in the heavily doped fluorite-like La<sub>2</sub>Ce<sub>2</sub>O<sub>7</sub> oxide, using a combination of X-ray diffraction, electron microscopy, optical absorption, Raman scattering and impedance spectroscopy. In all cases, materials with varying degree of 〈1<!--> <!-->1<!--> <!-->1〉 texture are compared with untextured samples. In this context, the most relevant Raman signatures are the fluorite-like mode at ∼448<!--> <!-->cm<sup>−1</sup> and a vacancy-related band at ∼578<!--> <!-->cm<sup>−1</sup>. Although remarkable changes were observed upon varying the sintering temperature or the excitation wavelength, both textured and untextured materials displayed similar evolution. A selective enhancement of the vacancy-related band was observed upon decreasing the excitation wavelength from 647 to 488<!--> <!-->nm, which is attributed to a resonance phenomenon involving vacancy-related electronic transitions. An indication of incipient vacancy ordering was given by the observation of an intense band at ∼346<!--> <!-->cm<sup>−1</sup>, denoting C-R<sub>2</sub>O<sub>3</sub>-like short-range order; its enhancement with the annealing temperature is attributed to the growth of the C-like regions. Conductivity was measured in textured and untextured, fully dense pellets, in the former along and across the texture direction. Impedance plots suggest that the conductivity is dominated by oxide ions and do not allow to separate a grain boundary contribution in these materials with grain size around 1–2<!--> <!-->μm. The conductivity amounts to around 10<sup>−5</sup> <!-->S/cm at 650<!--> <!-->K, with activation energy of 1.08–1.16<!--> <!-->eV in the temperature range from around 470 to 870<!--> <!-->K. Results were similar in textured and untextured materials. We conclude that there is no significant correlation between texture and vacancy concentration or vacancy ordering. A similar conclusion – no influence of texture – is reached concerning the electrical properties.</div></div>","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 5","pages":"Pages 318-329"},"PeriodicalIF":2.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.bsecv.2024.10.003
Amador C. Caballero
{"title":"Inteligencia artificial y materiales","authors":"Amador C. Caballero","doi":"10.1016/j.bsecv.2024.10.003","DOIUrl":"10.1016/j.bsecv.2024.10.003","url":null,"abstract":"","PeriodicalId":56330,"journal":{"name":"Boletin de la Sociedad Espanola de Ceramica y Vidrio","volume":"63 5","pages":"Page 317"},"PeriodicalIF":2.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}