Haozhang Liang, Xiangtao Lin, Nanshan Ma, Longqing He, Juxia Tong, Zhiwei Luo, Lingying Ye, Anxian Lu
The Er3+/Yb3+ co‐doped tellurite glasses and glass‐ceramics (GCs) containing the Gd2Te6O15 phase were successfully fabricated via the conventional melting‐quenching technique followed by a crystallization regime. The Er3+/Yb3+ co‐doped tellurite glasses generated intense up‐conversion green (524 and 546 nm) and red (658 nm) emissions when stimulated by a 980 nm laser. The up‐conversion green emission intensity increased by 68 and 46 times with the increase of the Yb3+/Er3+ ratio, and the optimal Yb3+/Er3+ ratio was found to be 8:1. The surface crystallization process of the Gd2Te6O15 GCs was confirmed through analysis of crystallization kinetics and microscopic morphology. The up‐conversion luminescence and lifetime of Er3+ ions were enhanced by the precipitation of low‐phonon‐energy Gd2Te6O15 crystals. The GC sample crystallized at 480°C for 4 h showed the highest luminescence intensity. The optical thermometry properties of Er3+ ions at thermally coupled energy levels (2H11/2/4S3/2→4I15/2) were explored. The Gd2Te6O15 GCs co‐doped with 0.25 mol% Er2O3 and 2.0 mol% Yb2O3 exhibited an excellent temperature relative sensitivity (Sr) of 1.22% K−1 at 293 K and a great repeatability of 98.07%. These results suggest that the Er3+/Yb3+ co‐doped Gd2Te6O15 GCs show promise for optical thermometry.
{"title":"Up‐conversion luminescence of Er3+/Yb3+ co‐doped Gd2Te6O15 tellurite glass‐ceramics for optical thermometry","authors":"Haozhang Liang, Xiangtao Lin, Nanshan Ma, Longqing He, Juxia Tong, Zhiwei Luo, Lingying Ye, Anxian Lu","doi":"10.1111/jace.20109","DOIUrl":"https://doi.org/10.1111/jace.20109","url":null,"abstract":"The Er<jats:sup>3+</jats:sup>/Yb<jats:sup>3+</jats:sup> co‐doped tellurite glasses and glass‐ceramics (GCs) containing the Gd<jats:sub>2</jats:sub>Te<jats:sub>6</jats:sub>O<jats:sub>15</jats:sub> phase were successfully fabricated via the conventional melting‐quenching technique followed by a crystallization regime. The Er<jats:sup>3+</jats:sup>/Yb<jats:sup>3+</jats:sup> co‐doped tellurite glasses generated intense up‐conversion green (524 and 546 nm) and red (658 nm) emissions when stimulated by a 980 nm laser. The up‐conversion green emission intensity increased by 68 and 46 times with the increase of the Yb<jats:sup>3+</jats:sup>/Er<jats:sup>3+</jats:sup> ratio, and the optimal Yb<jats:sup>3+</jats:sup>/Er<jats:sup>3+</jats:sup> ratio was found to be 8:1. The surface crystallization process of the Gd<jats:sub>2</jats:sub>Te<jats:sub>6</jats:sub>O<jats:sub>15</jats:sub> GCs was confirmed through analysis of crystallization kinetics and microscopic morphology. The up‐conversion luminescence and lifetime of Er<jats:sup>3+</jats:sup> ions were enhanced by the precipitation of low‐phonon‐energy Gd<jats:sub>2</jats:sub>Te<jats:sub>6</jats:sub>O<jats:sub>15</jats:sub> crystals. The GC sample crystallized at 480°C for 4 h showed the highest luminescence intensity. The optical thermometry properties of Er<jats:sup>3+</jats:sup> ions at thermally coupled energy levels (<jats:sup>2</jats:sup>H<jats:sub>11/2</jats:sub>/<jats:sup>4</jats:sup>S<jats:sub>3/2</jats:sub>→<jats:sup>4</jats:sup>I<jats:sub>15/2</jats:sub>) were explored. The Gd<jats:sub>2</jats:sub>Te<jats:sub>6</jats:sub>O<jats:sub>15</jats:sub> GCs co‐doped with 0.25 mol% Er<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> and 2.0 mol% Yb<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> exhibited an excellent temperature relative sensitivity (<jats:italic>S<jats:sub>r</jats:sub></jats:italic>) of 1.22% K<jats:sup>−1</jats:sup> at 293 K and a great repeatability of 98.07%. These results suggest that the Er<jats:sup>3+</jats:sup>/Yb<jats:sup>3+</jats:sup> co‐doped Gd<jats:sub>2</jats:sub>Te<jats:sub>6</jats:sub>O<jats:sub>15</jats:sub> GCs show promise for optical thermometry.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the influence of foreign and native point defects in magnesium oxide on the sintering process is examined. We have introduced dopants into magnesium oxide, with cations that share similar sizes but possess varying charges to minimize the direct impact of strain. The selected foreign cations were as follows: (1) Li1+, an acceptor that enhances the concentration of oxygen vacancies; (2) Sc3+, a donor that enhances the concentration of magnesium (metal) vacancies; and (3) Zn2+, an isovalent dopant. The results reveal that oxygen vacancies introduced by lithium doping greatly decrease the sintering temperature of magnesium oxide compared to the magnesium vacancies’ effect (scandium doping). Zinc doping was found to increase the surface oxygen vacancies with only a minor effect on the sintering temperature. Enhancing the oxygen vacancy concentration by lithium doping creates an additional mechanism for sintering because the anion sublattice is the backbone of the material, and oxygen ion diffusion is the rate‐limiting step. Scandium doping also has a sintering–promoting effect, yet a minor one. The doping factor analysis is considered and implies that aliovalent dopants do not affect the concentration of the fast‐diffusing species, which are native vacancy associates.
{"title":"The influence of point defects on the sintering of magnesium oxide","authors":"Rawan Halabi, Sasha Simotko, Yoed Tsur","doi":"10.1111/jace.20090","DOIUrl":"https://doi.org/10.1111/jace.20090","url":null,"abstract":"In this study, the influence of foreign and native point defects in magnesium oxide on the sintering process is examined. We have introduced dopants into magnesium oxide, with cations that share similar sizes but possess varying charges to minimize the direct impact of strain. The selected foreign cations were as follows: (1) Li<jats:sup>1+</jats:sup>, an acceptor that enhances the concentration of oxygen vacancies; (2) Sc<jats:sup>3+</jats:sup>, a donor that enhances the concentration of magnesium (metal) vacancies; and (3) Zn<jats:sup>2+</jats:sup>, an isovalent dopant. The results reveal that oxygen vacancies introduced by lithium doping greatly decrease the sintering temperature of magnesium oxide compared to the magnesium vacancies’ effect (scandium doping). Zinc doping was found to increase the surface oxygen vacancies with only a minor effect on the sintering temperature. Enhancing the oxygen vacancy concentration by lithium doping creates an <jats:italic>additional mechanism</jats:italic> for sintering because the anion sublattice is the backbone of the material, and oxygen ion diffusion is the rate‐limiting step. Scandium doping also has a sintering–promoting effect, yet a minor one. The doping factor analysis is considered and implies that aliovalent dopants do not affect the concentration of the fast‐diffusing species, which are native vacancy associates.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jifeng Yang, Lianfeng Yan, Lideng Ye, Guangheng Xiao, Kaige Wang, Yuling Liu, Ligang Zhang, Libin Liu, Yong Du
The K2O‐Al2O3‐SiO2 system is an important component of microcrystalline glass. The K2O‐Al2O3 and K2O‐SiO2 binary systems and the K2O‐Al2O3‐SiO2 ternary system were thermodynamically evaluated and optimized using the CALculation of PHAse Diagram (CALPHAD) method. The liquid phase is described by using the ionic two‐sublattice model, and the solid solutions involved in the ternary system are all described using the compound energy formalism (CEF) model. The new parameters obtained from the optimization are capable of describing the equilibrium phase relations of the ternary system and its subsystems, and the calculated thermodynamic properties of the ternary compounds are in good agreement with the experimental data.
K2O-Al2O3-SiO2 系统是微晶玻璃的重要组成部分。利用CALculation of PHAse Diagram（CALPHAD）方法对K2O-Al2O3和K2O-SiO2二元体系以及K2O-Al2O3-SiO2三元体系进行了热力学评估和优化。液相采用离子双亚晶格模型进行描述，三元体系中涉及的固溶体均采用复能形式主义（CEF）模型进行描述。优化得到的新参数能够描述三元体系及其子体系的平衡相关系，计算得到的三元化合物热力学性质与实验数据吻合良好。
{"title":"Thermodynamic evaluation and optimization of the K2O‐Al2O3‐SiO2 system","authors":"Jifeng Yang, Lianfeng Yan, Lideng Ye, Guangheng Xiao, Kaige Wang, Yuling Liu, Ligang Zhang, Libin Liu, Yong Du","doi":"10.1111/jace.20093","DOIUrl":"https://doi.org/10.1111/jace.20093","url":null,"abstract":"The K<jats:sub>2</jats:sub>O‐Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>‐SiO<jats:sub>2</jats:sub> system is an important component of microcrystalline glass. The K<jats:sub>2</jats:sub>O‐Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> and K<jats:sub>2</jats:sub>O‐SiO<jats:sub>2</jats:sub> binary systems and the K<jats:sub>2</jats:sub>O‐Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>‐SiO<jats:sub>2</jats:sub> ternary system were thermodynamically evaluated and optimized using the CALculation of PHAse Diagram (CALPHAD) method. The liquid phase is described by using the ionic two‐sublattice model, and the solid solutions involved in the ternary system are all described using the compound energy formalism (CEF) model. The new parameters obtained from the optimization are capable of describing the equilibrium phase relations of the ternary system and its subsystems, and the calculated thermodynamic properties of the ternary compounds are in good agreement with the experimental data.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haoran Zou, Wen Zhang, Jinyong Zhang, Lin Ren, Weimin Wang, Fan Zhang, Bin Li, Zhengyi Fu
High‐performance MAX phase‐based composites were developed to overcome the inherent low hardness and low strength of MAX phases by combining lattice distortion‐induced strengthening, texture strengthening, and second‐phase particle strengthening. Textured high‐entropy M4AlC3/Al2O3 (M = Ti, V, Mo, Nb, Ta) composites with different Al2O3 contents were prepared using spark plasma sintering at 1350°C for 70 min. The microstructures of all samples with different compositions were characterized in detail. It was found that as the Al2O3 content increased, the grain size of the high‐entropy M4AlC3 phase gradually decreased, and the aggregation of Al2O3 became more severe. Based on this, the density, hardness, strength, and fracture toughness of all composites were tested. The results indicate that all textured composites exhibit significant anisotropy in their properties, with the high‐entropy M4AlC3/15 vol%Al2O3 composite showing the best overall performance. Additionally, the mechanism of performance improvement was systematically discussed. This work provides an important reference for the subsequent preparation of high‐performance MAX phase‐based composites.
通过结合晶格畸变诱导强化、纹理强化和第二相颗粒强化，开发了基于 MAX 相的高性能复合材料，以克服 MAX 相固有的低硬度和低强度问题。采用 1350°C 下 70 分钟的火花等离子烧结法制备了不同 Al2O3 含量的纹理高熵 M4AlC3/Al2O3（M = Ti、V、Mo、Nb、Ta）复合材料。对不同成分的所有样品的微观结构进行了详细表征。研究发现，随着 Al2O3 含量的增加，高熵 M4AlC3 相的晶粒尺寸逐渐减小，Al2O3 的聚集现象变得更加严重。在此基础上，测试了所有复合材料的密度、硬度、强度和断裂韧性。结果表明，所有纹理复合材料的性能都表现出明显的各向异性，其中高熵 M4AlC3/15 vol%Al2O3 复合材料的综合性能最好。此外，还系统地讨论了性能改善的机理。这项工作为后续制备高性能 MAX 相基复合材料提供了重要参考。
{"title":"Microstructure and mechanical properties of textured high‐entropy M₄AlC₃/Al₂O₃ (M = Ti, V, Mo, Nb, Ta) composites","authors":"Haoran Zou, Wen Zhang, Jinyong Zhang, Lin Ren, Weimin Wang, Fan Zhang, Bin Li, Zhengyi Fu","doi":"10.1111/jace.20082","DOIUrl":"https://doi.org/10.1111/jace.20082","url":null,"abstract":"High‐performance MAX phase‐based composites were developed to overcome the inherent low hardness and low strength of MAX phases by combining lattice distortion‐induced strengthening, texture strengthening, and second‐phase particle strengthening. Textured high‐entropy M<jats:sub>4</jats:sub>AlC<jats:sub>3</jats:sub>/Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> (M = Ti, V, Mo, Nb, Ta) composites with different Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> contents were prepared using spark plasma sintering at 1350°C for 70 min. The microstructures of all samples with different compositions were characterized in detail. It was found that as the Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> content increased, the grain size of the high‐entropy M<jats:sub>4</jats:sub>AlC<jats:sub>3</jats:sub> phase gradually decreased, and the aggregation of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> became more severe. Based on this, the density, hardness, strength, and fracture toughness of all composites were tested. The results indicate that all textured composites exhibit significant anisotropy in their properties, with the high‐entropy M<jats:sub>4</jats:sub>AlC<jats:sub>3</jats:sub>/15 vol%Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> composite showing the best overall performance. Additionally, the mechanism of performance improvement was systematically discussed. This work provides an important reference for the subsequent preparation of high‐performance MAX phase‐based composites.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lead‐based piezo‐ceramics like lead zirconate titanate (PZT) are a mainstay for many piezoelectric applications. However, lead oxide (PbO) evaporation during sintering poses a significant environmental challenge. Flash sintering (FS) is a novel technique that can densify ceramics in seconds and at a much lower furnace temperature. The liquid‐phase FS (LPFS) of PZT (Pb (Zr0.5Ti0.5) O3, with 3 wt.% Cu2O and PbO in the molar ratio of 1:4) is investigated in this work. Further, a comparison has been made among the lead loss, dielectric, and piezoelectric properties of flash‐sintered and conventionally liquid‐phase‐sintered PZT. It has been observed that the evaporation of PbO has been brought down 3–5 times by FS. The dielectric constant of LPFS PZT is significantly higher, especially at higher frequencies with lower dielectric loss. An enhanced piezoelectric coefficient in flash‐sintered PZT has also been observed. The LPFS of PZT shows that the lead loss can be brought down significantly with the added benefit of enhanced dielectric and piezoelectric properties. XRD and Rietveld analysis show an increase in tetragonality after FS in comparison with conventional sintering. XPS and ESR studies show a difference in defect concentration after FS in comparison with conventional sintering that is likely responsible for the enhanced dielectric and piezoelectric properties.
{"title":"Novel liquid–phase flash sintering of lead zirconate titanate piezo‐ceramics","authors":"Kumar Sadanand Arya, Ram Prakash Singh, Tamoghna Chakrabarti","doi":"10.1111/jace.20075","DOIUrl":"https://doi.org/10.1111/jace.20075","url":null,"abstract":"Lead‐based piezo‐ceramics like lead zirconate titanate (PZT) are a mainstay for many piezoelectric applications. However, lead oxide (PbO) evaporation during sintering poses a significant environmental challenge. Flash sintering (FS) is a novel technique that can densify ceramics in seconds and at a much lower furnace temperature. The liquid‐phase FS (LPFS) of PZT (Pb (Zr<jats:sub>0.5</jats:sub>Ti<jats:sub>0.5</jats:sub>) O<jats:sub>3</jats:sub>, with 3 wt.% Cu<jats:sub>2</jats:sub>O and PbO in the molar ratio of 1:4) is investigated in this work. Further, a comparison has been made among the lead loss, dielectric, and piezoelectric properties of flash‐sintered and conventionally liquid‐phase‐sintered PZT. It has been observed that the evaporation of PbO has been brought down 3–5 times by FS. The dielectric constant of LPFS PZT is significantly higher, especially at higher frequencies with lower dielectric loss. An enhanced piezoelectric coefficient in flash‐sintered PZT has also been observed. The LPFS of PZT shows that the lead loss can be brought down significantly with the added benefit of enhanced dielectric and piezoelectric properties. XRD and Rietveld analysis show an increase in tetragonality after FS in comparison with conventional sintering. XPS and ESR studies show a difference in defect concentration after FS in comparison with conventional sintering that is likely responsible for the enhanced dielectric and piezoelectric properties.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jared S. Aaldenberg, Marvin W. Kemmerer, James E. Webb
Delayed fracture occurs when cracks grow subcritically prior to achieving KIC. Glass science research in this area has focused almost exclusively on non ion‐exchanged glasses. In this study, an ion‐exchange strengthened aluminosilicate glass was intentionally damaged to measure delayed fracture behavior. Damage was applied both pre and post ion‐exchange and the role of heat‐treatments was investigated. It was found that the delayed fracture likelihood was reduced for samples that were heat‐treated in an environment containing water vapor. An increase in the static fatigue limit was measured for increasing temperature and it was hypothesized that crack toughening takes place during the heat‐treatment due to a water‐assisted stress relaxation mechanism.
{"title":"Delayed fracture of ion‐exchange strengthened alkali‐aluminosilicate glass","authors":"Jared S. Aaldenberg, Marvin W. Kemmerer, James E. Webb","doi":"10.1111/jace.19993","DOIUrl":"https://doi.org/10.1111/jace.19993","url":null,"abstract":"Delayed fracture occurs when cracks grow subcritically prior to achieving <jats:italic>K</jats:italic><jats:sub>IC</jats:sub>. Glass science research in this area has focused almost exclusively on non ion‐exchanged glasses. In this study, an ion‐exchange strengthened aluminosilicate glass was intentionally damaged to measure delayed fracture behavior. Damage was applied both pre and post ion‐exchange and the role of heat‐treatments was investigated. It was found that the delayed fracture likelihood was reduced for samples that were heat‐treated in an environment containing water vapor. An increase in the static fatigue limit was measured for increasing temperature and it was hypothesized that crack toughening takes place during the heat‐treatment due to a water‐assisted stress relaxation mechanism.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The common feature of non‐ergodic systems is an internal timescale that greatly exceeds the external observational timescale . This kinetic state of broken ergodicity occurs in many systems, with profound thermodynamic implications. In this work, we present a review of non‐ergodic physical systems focused on the common origins of non‐ergodic behavior across diverse material systems. We begin with a theoretical discussion of energy landscapes and two treatments of thermodynamics in broken ergodic systems. We then discuss several characteristic material classes that exhibit non‐ergodic behavior, describing the process of ergodic breakdown and its signatures for each. The disordered nature and frustration of different energetic interactions in the example systems are discussed as the possible origin of non‐ergodic dynamics. We conclude with several considerations that can assist in the identification of non‐ergodic behavior. This review intends to unify the behavior of a diverse group of physical systems with a common description to aid future discussions between these fields of study.
{"title":"Frozen in time: A review of non‐ergodic physical systems","authors":"Aaron M. Bossen, John C. Mauro","doi":"10.1111/jace.20092","DOIUrl":"https://doi.org/10.1111/jace.20092","url":null,"abstract":"The common feature of non‐ergodic systems is an internal timescale that greatly exceeds the external observational timescale . This kinetic state of broken ergodicity occurs in many systems, with profound thermodynamic implications. In this work, we present a review of non‐ergodic physical systems focused on the common origins of non‐ergodic behavior across diverse material systems. We begin with a theoretical discussion of energy landscapes and two treatments of thermodynamics in broken ergodic systems. We then discuss several characteristic material classes that exhibit non‐ergodic behavior, describing the process of ergodic breakdown and its signatures for each. The disordered nature and frustration of different energetic interactions in the example systems are discussed as the possible origin of non‐ergodic dynamics. We conclude with several considerations that can assist in the identification of non‐ergodic behavior. This review intends to unify the behavior of a diverse group of physical systems with a common description to aid future discussions between these fields of study.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Otávio Henrique Borges, Francisco Gil Coury, Nora Brachhold, Christos Gregorius Aneziris, Victor Carlos Pandolfelli
On the rising demand for eco‐friendly refractories, reducing the use of likely toxic magnesia‐chromium aggregates remains a challenge. Previous studies by some of the authors have proposed Cr‐free alternative compositions, although the morphology of the spinel precipitates has varied across the different suggested systems. The mechanisms involved in the formation of these distinct morphologies were unclear and, therefore, are the focus of this work. In all compositions, SEM/electron backscatter diffraction revealed cube–cube orientation relationships between matrix and precipitates, indicating that their formation is influenced by the lattice parameter misfit (δ), which was measured using synchrotron X‐ray diffraction. It could be concluded that coarser and spherical precipitates form to minimize their surface‐to‐volume ratio in compositions with high absolute δ‐values. Conversely, low‐misfit systems enable the spinel to form a 3D‐network. The potential use of this knowledge to tailor the microstructure of novel compositions was demonstrated by a small Nb2O5 addition into one of the proposed compositions.
{"title":"Designing eco‐friendly alternative microstructures for magnesia‐chromium aggregates","authors":"Otávio Henrique Borges, Francisco Gil Coury, Nora Brachhold, Christos Gregorius Aneziris, Victor Carlos Pandolfelli","doi":"10.1111/jace.20084","DOIUrl":"https://doi.org/10.1111/jace.20084","url":null,"abstract":"On the rising demand for eco‐friendly refractories, reducing the use of likely toxic magnesia‐chromium aggregates remains a challenge. Previous studies by some of the authors have proposed Cr‐free alternative compositions, although the morphology of the spinel precipitates has varied across the different suggested systems. The mechanisms involved in the formation of these distinct morphologies were unclear and, therefore, are the focus of this work. In all compositions, SEM/electron backscatter diffraction revealed cube–cube orientation relationships between matrix and precipitates, indicating that their formation is influenced by the lattice parameter misfit (<jats:italic>δ</jats:italic>), which was measured using synchrotron X‐ray diffraction. It could be concluded that coarser and spherical precipitates form to minimize their surface‐to‐volume ratio in compositions with high absolute <jats:italic>δ</jats:italic>‐values. Conversely, low‐misfit systems enable the spinel to form a 3D‐network. The potential use of this knowledge to tailor the microstructure of novel compositions was demonstrated by a small Nb<jats:sub>2</jats:sub>O<jats:sub>5</jats:sub> addition into one of the proposed compositions.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zirconia/alumina composites are a family of structural ceramics with excellent mechanical properties. In order to improve the engineering reliability of this kind of composites, the uniform spatial distribution of the two phases is necessary. One of the effective methods to achieve this goal is to synthesize uniform zirconia–alumina composite nano powders. Here, we report mechanochemical synthesis of zirconia–alumina composite nano powders, in which dehydration and crystallization of Zr–Y–Al hydroxide can be achieved under milling conditions, leading to the formation of the tetragonal zirconia phase with supersaturated Al3+. The mechanochemically synthesized powders have the uniform element distribution and a fine primary crystallite size of around 11 nm. After sintering at 1400°C, t‐ZrO2/α‐Al2O3 composite with the uniform phase distribution and grain size distribution could be obtained. To uncover the full benefits of these supersaturated composite powders in ceramic processing, future work could be done to break up the deagglomerations and improve the sinterability of the mechanochemically synthesized zirconia/alumina powders.
{"title":"Mechanochemical dehydration and crystallization of supersaturated zirconia–alumina composite nano powders","authors":"Yilei Huang, Hongbing Yang, Ruoshi Zhao, Chang‐An Wang, Yanhao Dong","doi":"10.1111/jace.20106","DOIUrl":"https://doi.org/10.1111/jace.20106","url":null,"abstract":"Zirconia/alumina composites are a family of structural ceramics with excellent mechanical properties. In order to improve the engineering reliability of this kind of composites, the uniform spatial distribution of the two phases is necessary. One of the effective methods to achieve this goal is to synthesize uniform zirconia–alumina composite nano powders. Here, we report mechanochemical synthesis of zirconia–alumina composite nano powders, in which dehydration and crystallization of Zr–Y–Al hydroxide can be achieved under milling conditions, leading to the formation of the tetragonal zirconia phase with supersaturated Al<jats:sup>3+</jats:sup>. The mechanochemically synthesized powders have the uniform element distribution and a fine primary crystallite size of around 11 nm. After sintering at 1400°C, <jats:italic>t</jats:italic>‐ZrO<jats:sub>2</jats:sub>/<jats:italic>α</jats:italic>‐Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> composite with the uniform phase distribution and grain size distribution could be obtained. To uncover the full benefits of these supersaturated composite powders in ceramic processing, future work could be done to break up the deagglomerations and improve the sinterability of the mechanochemically synthesized zirconia/alumina powders.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This investigation explores the impact of incorporating graphene (Gr) reinforcement on the microstructure, mechanical properties, corrosion behavior, and biocompatibility of a composite derived from a magnesium–calcium (Mg–Ca) alloy. Two concentrations of Gr (0.1% and 0.2%) were introduced to an Mg–Ca alloy. The addition of 0.1% Gr resulted in a refined grain structure, enhancing both tensile and compression strength. However, electrochemical analysis and immersion testing revealed an increase in corrosion rate () with the incorporation of Gr. Although the corrosion rate of the Mg–Ca‐0.1%Gr composite was comparable to that of Mg–Ca, the Mg–Ca–0.2%Gr exhibited higher corrosion rates attributed to the enhancement of micro‐galvanic corrosion. Interestingly, cell survival rate tests demonstrated improved biocompatibility for the Mg–Ca–0.1%Gr sample, emphasizing its potential for applications in the biomedical domain, which requires enhanced mechanical strength, corrosion resistance, and biocompatibility.
本研究探讨了加入石墨烯（Gr）增强材料对镁-钙（Mg-Ca）合金复合材料的微观结构、机械性能、腐蚀行为和生物相容性的影响。在镁钙合金中引入了两种浓度的 Gr（0.1% 和 0.2%）。添加 0.1% Gr 后，晶粒结构更加细化，抗拉强度和抗压强度都有所提高。然而，电化学分析和浸泡测试表明，加入 Gr 后腐蚀速率（）会增加。虽然 Mg-Ca-0.1%Gr 复合材料的腐蚀速率与 Mg-Ca 相当，但 Mg-Ca-0.2%Gr 表现出更高的腐蚀速率，这归因于微电蚀作用的增强。有趣的是，细胞存活率测试表明，Mg-Ca-0.1%Gr 样品的生物相容性得到了改善，强调了其在生物医学领域的应用潜力，该领域需要更高的机械强度、耐腐蚀性和生物相容性。
{"title":"The impact of graphene on the mechanical properties, corrosion behavior, and biocompatibility of an Mg–Ca alloy","authors":"Song‐Jeng Huang, Chih‐Feng Wang, Murugan Subramani, Sivakumar Selvaraju, Veeramanikandan Rajagopal, Chao‐Ching Chiang, Fang‐Fu Fan","doi":"10.1111/jace.20091","DOIUrl":"https://doi.org/10.1111/jace.20091","url":null,"abstract":"This investigation explores the impact of incorporating graphene (Gr) reinforcement on the microstructure, mechanical properties, corrosion behavior, and biocompatibility of a composite derived from a magnesium–calcium (Mg–Ca) alloy. Two concentrations of Gr (0.1% and 0.2%) were introduced to an Mg–Ca alloy. The addition of 0.1% Gr resulted in a refined grain structure, enhancing both tensile and compression strength. However, electrochemical analysis and immersion testing revealed an increase in corrosion rate () with the incorporation of Gr. Although the corrosion rate of the Mg–Ca‐0.1%Gr composite was comparable to that of Mg–Ca, the Mg–Ca–0.2%Gr exhibited higher corrosion rates attributed to the enhancement of micro‐galvanic corrosion. Interestingly, cell survival rate tests demonstrated improved biocompatibility for the Mg–Ca–0.1%Gr sample, emphasizing its potential for applications in the biomedical domain, which requires enhanced mechanical strength, corrosion resistance, and biocompatibility.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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