Pub Date : 2024-11-09DOI: 10.1016/j.jnoncrysol.2024.123308
N. Danchova, R. Tsekov, D. Shandurkov, S. Gutzov, L. Lyubenova, L. Mihaylov, T. Spassov
A novel sol-gel strategy for the preparation of silica nanocomposites, containing gold nanoparticles (AuNPs), Au(I)-thiolate complexes (Au-SC12) or both disperse phases is demonstrated. The color of the species depends on the size and surrounding of the AuNPs. The nanocomposites obtained are characterized with UV/Vis reflectance spectroscopy, X-Ray diffraction, TEM / EDAX and thermal conductivity measurements. An analysis of the UV/VIS spectra, based on Mie's theory, suggests the presence of 5 - 30 nm AuNPs with different chemical surroundings. Heating of the nanocomposites at 700 °C leads to red or violet colored SiO2:AuNPs powders. The thermal conductivity of the nanocomposites is about 0.05–0.07 W/m.K, depending on sintering and chemical composition. A discussion about the microstructure of the composites is also presented.
{"title":"Silica gels doped with gold nanoparticles and gold thiolate complexes: The effect of heating and preparation conditions","authors":"N. Danchova, R. Tsekov, D. Shandurkov, S. Gutzov, L. Lyubenova, L. Mihaylov, T. Spassov","doi":"10.1016/j.jnoncrysol.2024.123308","DOIUrl":"10.1016/j.jnoncrysol.2024.123308","url":null,"abstract":"<div><div>A novel sol-gel strategy for the preparation of silica nanocomposites, containing gold nanoparticles (AuNPs), Au(I)-thiolate complexes (Au-SC12) or both disperse phases is demonstrated. The color of the species depends on the size and surrounding of the AuNPs. The nanocomposites obtained are characterized with UV/Vis reflectance spectroscopy, X-Ray diffraction, TEM / EDAX and thermal conductivity measurements. An analysis of the UV/VIS spectra, based on Mie's theory, suggests the presence of 5 - 30 nm AuNPs with different chemical surroundings. Heating of the nanocomposites at 700 °C leads to red or violet colored SiO<sub>2</sub>:AuNPs powders. The thermal conductivity of the nanocomposites is about 0.05–0.07 W/m.K, depending on sintering and chemical composition. A discussion about the microstructure of the composites is also presented.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"648 ","pages":"Article 123308"},"PeriodicalIF":3.2,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-11-09DOI: 10.1016/j.jnoncrysol.2024.123296
Vladimir A. Yuryev , Oleg V. Uvarov , Tatyana V. Yuryeva , Victor P. Kalinushkin
Recently, photoluminescence tomography based on the confocal laser scanning microscopy with two-photon excitation has been developed to study the distribution of point and extended defects in the bulk of ZnSe laser crystals. This article presents the use of the tomography to investigate luminescent micro inclusions in transparent amorphous media such as silicate glass. Studies of CdZnSSe crystals synthesized in a silicate glass melt have been carried out using the tomography with both two-photon and single-photon excitation of luminescence. Zn-rich glass manufactured in the 19th century has been found to contain micron-sized crystals of CdZnSSe (, ) of hexagonal crystal system exhibiting intense photoluminescence. The photoluminescence band of these crystals has been found to peak at about 2.1 eV () at 300 K. Minor shifts in the maximum of bands and changes in their shape in individual crystals or at tomogram points within the crystal are associated with variations in their composition. Changes in the photoluminescence band shape and maximum due to the excitation of luminescence in CdZnSSe crystallites by laser radiation of different energies have also been observed in this study.
最近，基于双光子激发共焦激光扫描显微镜的光致发光层析技术被开发出来，用于研究 ZnSe 激光晶体块体中点状和扩展缺陷的分布。本文介绍了如何利用层析技术来研究透明非晶介质（如硅酸盐玻璃）中的发光微夹杂物。我们利用层析成像技术，通过双光子和单光子激发发光，对在硅酸盐玻璃熔体中合成的 CdZnSSe 晶体进行了研究。在 19 世纪制造的富锌玻璃中发现了微米大小的 CdξZn1-ξSζSe1-ζ （ξ≈0.5，ζ≈0.5）六方晶系晶体，这些晶体显示出强烈的光致发光。这些晶体的光致发光带在 300 K 时达到约 2.1 eV 的峰值（∼590 纳米）。晶体内单个晶体或层析点的光致发光带最大值的微小移动及其形状的变化与晶体成分的变化有关。本研究还观察到不同能量的激光辐射在 CdZnSSe 晶体中激发发光所导致的光致发光带形状和最大值的变化。
{"title":"Application of confocal laser scanning microscopy to investigation of micro crystals in transparent amorphous media: Photoluminescence tomography and spectroscopy of CdZnSSe crystallites in historical silicate glass","authors":"Vladimir A. Yuryev , Oleg V. Uvarov , Tatyana V. Yuryeva , Victor P. Kalinushkin","doi":"10.1016/j.jnoncrysol.2024.123296","DOIUrl":"10.1016/j.jnoncrysol.2024.123296","url":null,"abstract":"<div><div>Recently, photoluminescence tomography based on the confocal laser scanning microscopy with two-photon excitation has been developed to study the distribution of point and extended defects in the bulk of ZnSe laser crystals. This article presents the use of the tomography to investigate luminescent micro inclusions in transparent amorphous media such as silicate glass. Studies of CdZnSSe crystals synthesized in a silicate glass melt have been carried out using the tomography with both two-photon and single-photon excitation of luminescence. Zn-rich glass manufactured in the 19th century has been found to contain micron-sized crystals of Cd<span><math><msub><mrow></mrow><mrow><mi>ξ</mi></mrow></msub></math></span>Zn<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>ξ</mi></mrow></msub></math></span>S<span><math><msub><mrow></mrow><mrow><mi>ζ</mi></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>ζ</mi></mrow></msub></math></span> (<span><math><mrow><mi>ξ</mi><mo>≈</mo><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span>, <span><math><mrow><mi>ζ</mi><mo>≈</mo><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span>) of hexagonal crystal system exhibiting intense photoluminescence. The photoluminescence band of these crystals has been found to peak at about 2.1 eV (<span><math><mrow><mo>∼</mo><mn>590</mn><mspace></mspace><mi>nm</mi></mrow></math></span>) at 300 K. Minor shifts in the maximum of bands and changes in their shape in individual crystals or at tomogram points within the crystal are associated with variations in their composition. Changes in the photoluminescence band shape and maximum due to the excitation of luminescence in CdZnSSe crystallites by laser radiation of different energies have also been observed in this study.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"648 ","pages":"Article 123296"},"PeriodicalIF":3.2,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653390","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 acoustic and acousto-optic (AO) properties of the Ga10Ge15Te75 glass, which is promising for creation of AO devices operating with the near and middle infrared optical radiation, are studied. In this paper, the experimental results for the longitudinal and shear acoustic waves phase velocities and the AO figure of merit (M2) in case of isotropic diffraction by these waves are presented. All measurements are carried out for the 3.39 µm optical wavelength. The obtained M2 magnitudes turned out to be close to 1000·10–15s3/kg that significantly exceeds the typical values observed in germanium (Ge) crystal – the basic material for middle infrared AO devices fabrication. The experimentally determined longitudinal acoustic wave attenuation coefficient for 100 MHz ultrasound frequency turns out to be 1.32 ± 0.05 cm-1. Finally, the acoustic and AO properties of telluride based glasses with the close chemical composition, namely Ga10Ge15Te75, Si25Te75 and Ge25Se15Te60 glasses, are compared.
Ga10Ge15Te75 玻璃具有良好的声学和声光（AO）特性，有望用于制造使用近红外和中红外光辐射的 AO 设备，本文对这种玻璃的声学和声光特性进行了研究。本文介绍了纵向声波和剪切声波相位速度的实验结果，以及这些声波在各向同性衍射情况下的 AO 优点系数 (M2)。所有测量都是在 3.39 µm 光波长下进行的。所获得的 M2 值接近 1000-10-15s3/kg，大大超过了在锗晶体中观察到的典型值--锗晶体是制造中红外自动光学器件的基本材料。实验测定的 100 MHz 超声波频率的纵向声波衰减系数为 1.32 ± 0.05 cm-1。最后，比较了化学成分接近的碲基玻璃（即 Ga10Ge15Te75、Si25Te75 和 Ge25Se15Te60 玻璃）的声学和 AO 特性。
{"title":"Acoustic and acousto-optic properties of Ga10Ge15Te75 glass","authors":"V.S. Khorkin , E.I. Kostyleva , S.N. Mantsevich , A.P. Velmuzhov , E.A. Tyurina , M.V. Sukhanov , V.S. Shiryaev","doi":"10.1016/j.jnoncrysol.2024.123299","DOIUrl":"10.1016/j.jnoncrysol.2024.123299","url":null,"abstract":"<div><div>The acoustic and acousto-optic (AO) properties of the Ga<sub>10</sub>Ge<sub>15</sub>Te<sub>75</sub> glass, which is promising for creation of AO devices operating with the near and middle infrared optical radiation, are studied. In this paper, the experimental results for the longitudinal and shear acoustic waves phase velocities and the AO figure of merit (<em>M</em><sub>2</sub>) in case of isotropic diffraction by these waves are presented. All measurements are carried out for the 3.39 µm optical wavelength. The obtained <em>M</em><sub>2</sub> magnitudes turned out to be close to 1000·10<sup>–15</sup>s<sup>3</sup>/kg that significantly exceeds the typical values observed in germanium (Ge) crystal – the basic material for middle infrared AO devices fabrication. The experimentally determined longitudinal acoustic wave attenuation coefficient for 100 MHz ultrasound frequency turns out to be 1.32 ± 0.05 cm<sup>-1</sup>. Finally, the acoustic and AO properties of telluride based glasses with the close chemical composition, namely Ga<sub>10</sub>Ge<sub>15</sub>Te<sub>75</sub>, Si<sub>25</sub>Te<sub>75</sub> and Ge<sub>25</sub>Se<sub>15</sub>Te<sub>60</sub> glasses, are compared.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"648 ","pages":"Article 123299"},"PeriodicalIF":3.2,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653389","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}
Pub Date : 2024-11-07DOI: 10.1016/j.jnoncrysol.2024.123305
Chengqiao Yang, Minhua Sun
Structural heterogeneity plays a key role in the dynamics and physical properties of metallic glasses. To date, there has been a lack of an effective and general parameter to describe and compare structural heterogeneity among different alloys. In this study, we introduce a new parameter, the spatial heterogeneity coefficient, to quantify the microstructural heterogeneity among metallic glasses (MGs). Using it, we investigated the microstructural heterogeneity of Cu50Zr50 and Ni50Zr50 MGs. We found that the Cu50Zr50 alloy shows higher structural heterogeneity than Ni50Zr50 across all temperatures, as observed from both five- and four-fold symmetric perspectives. Concurrently, Cu50Zr50 displays stronger dynamic heterogeneity and stronger dynamics fragility as it approaches the glass transition. These characteristics endow Cu50Zr50 with a higher GFA than Ni50Zr50 MG. This study provides a novel approach to understanding the structural heterogeneity in MGs and its impact on their dynamic behavior.
{"title":"Structural and dynamic heterogeneities in Cu50Zr50 and Ni50Zr50 Metallic Glasses","authors":"Chengqiao Yang, Minhua Sun","doi":"10.1016/j.jnoncrysol.2024.123305","DOIUrl":"10.1016/j.jnoncrysol.2024.123305","url":null,"abstract":"<div><div>Structural heterogeneity plays a key role in the dynamics and physical properties of metallic glasses. To date, there has been a lack of an effective and general parameter to describe and compare structural heterogeneity among different alloys. In this study, we introduce a new parameter, the spatial heterogeneity coefficient, to quantify the microstructural heterogeneity among metallic glasses (MGs). Using it, we investigated the microstructural heterogeneity of Cu50Zr50 and Ni50Zr50 MGs. We found that the Cu50Zr50 alloy shows higher structural heterogeneity than Ni50Zr50 across all temperatures, as observed from both five- and four-fold symmetric perspectives. Concurrently, Cu50Zr50 displays stronger dynamic heterogeneity and stronger dynamics fragility as it approaches the glass transition. These characteristics endow Cu50Zr50 with a higher GFA than Ni50Zr50 MG. This study provides a novel approach to understanding the structural heterogeneity in MGs and its impact on their dynamic behavior.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"647 ","pages":"Article 123305"},"PeriodicalIF":3.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653192","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}
Pub Date : 2024-11-06DOI: 10.1016/j.jnoncrysol.2024.123285
Israel F. Cardoso , Raí F. Jucá , Francisco G.S. Oliveira , Igor F. Vasconcelos , Gilberto D. Saraiva , Meirielle M. de Góis , Vinicius P.S. Caldeira , Keurison F. Magalhães , João M. Soares
In this research, we make use of mineral waste composite with elemental composition of Si, Al, Ca, Mg, K and Fe to synthesize magnetic aluminosilicate glasses (MAGlass). The produced MAGlass presented interesting magnetic and optical properties due to the presence of iron with different valence states. The elemental composition was measured by X-ray fluorescence spectroscopy. X-ray diffraction analysis confirmed the glass amorphous nature. Thermal properties such as glass transition temperature and thermal stability were analyzed by differential scanning calorimetry. The nature of the glass chemical bond structure was studied by FT-Raman analysis. UV–Vis spectroscopy studied the transmittance and absorbance in each sample, approaching the main electronic transitions, Racah parameters and gap energy. Mössbauer and magnetization measurements showed different iron valency states and interesting asperomagnetism and speromagnetism behaviors, with variations among the Fe2＋ and Fe in the MAGlass samples.
在这项研究中，我们利用元素组成为 Si、Al、Ca、Mg、K 和 Fe 的矿物废料复合材料合成了磁性铝硅酸盐玻璃（MAGlass）。由于含有不同价态的铁，所制得的磁性铝硅酸盐玻璃具有有趣的磁性和光学特性。元素组成是通过 X 射线荧光光谱测定的。X 射线衍射分析证实了玻璃的无定形性质。差示扫描量热法分析了玻璃转化温度和热稳定性等热特性。通过傅立叶变换拉曼光谱分析研究了玻璃化学键结构的性质。紫外可见光谱法研究了每个样品的透射率和吸光度，接近主要的电子跃迁、拉卡赫参数和间隙能。莫斯鲍尔和磁化测量显示了不同的铁价态以及有趣的超磁和疏磁行为，MAGlass 样品中的 Fe2＋ 和 Fe2.5+ 之间存在变化。
{"title":"Asperomagnetism and speromagnetism in magnetic aluminosilicate glasses","authors":"Israel F. Cardoso , Raí F. Jucá , Francisco G.S. Oliveira , Igor F. Vasconcelos , Gilberto D. Saraiva , Meirielle M. de Góis , Vinicius P.S. Caldeira , Keurison F. Magalhães , João M. Soares","doi":"10.1016/j.jnoncrysol.2024.123285","DOIUrl":"10.1016/j.jnoncrysol.2024.123285","url":null,"abstract":"<div><div>In this research, we make use of mineral waste composite with elemental composition of Si, Al, Ca, Mg, K and Fe to synthesize magnetic aluminosilicate glasses (MAGlass). The produced MAGlass presented interesting magnetic and optical properties due to the presence of iron with different valence states. The elemental composition was measured by X-ray fluorescence spectroscopy. X-ray diffraction analysis confirmed the glass amorphous nature. Thermal properties such as glass transition temperature and thermal stability were analyzed by differential scanning calorimetry. The nature of the glass chemical bond structure was studied by FT-Raman analysis. UV–Vis spectroscopy studied the transmittance and absorbance in each sample, approaching the main electronic transitions, Racah parameters and gap energy. Mössbauer and magnetization measurements showed different iron valency states and interesting asperomagnetism and speromagnetism behaviors, with variations among the Fe<sup>2＋</sup> and Fe<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>.</mo><mn>5</mn><mo>+</mo></mrow></msup></math></span> in the MAGlass samples.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"647 ","pages":"Article 123285"},"PeriodicalIF":3.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593431","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}
Pub Date : 2024-11-04DOI: 10.1016/j.jnoncrysol.2024.123303
Hailong Dong , Fangling Jiang , Min Qian , Tianfeng Xue , Sijun Fan , Minzhi Ruan , Zhongdi Li , Shubin Chen , Lu Deng
Vitrification has gained global recognition as one of the most mature techniques for solidification of high-level nuclear waste, and borosilicate glass has been widely used in various countries as the base material. However, iron aluminophosphate glass also found advantages in solidify waste forms containing high concentrations of Zr, Mo and rare earth elements. In this work, oxidation states of Fe and its structural role of sodium iron aluminophosphate glass have been investigated using X-ray absorption fine structure spectroscopy experiments and molecular dynamic simulations. Results show that both the Fe2+ concentration and the average phosphorus number around Fe increase with the replacement of Na by Fe; whereas, the average oxygen number around Fe decreases. Fe2+ ions are mainly four-coordinated, and Fe3+ ions are mainly five-coordinated. Moreover, additional Fe content leads to the gradual replacement of Al/P–O–P linkages by Fe2+–O–P linkages, resulting in the enhancement of the chemical durability of the glass.
作为最成熟的高水平核废料固化技术之一，玻璃固化技术已得到全球认可，各国已广泛采用硼硅酸盐玻璃作为基础材料。然而，磷酸铁铝玻璃在固化含有高浓度锆、钼和稀土元素的废物形式方面也具有优势。在这项工作中，利用 X 射线吸收精细结构光谱实验和分子动力学模拟研究了铁铝酸钠玻璃中铁的氧化态及其结构作用。结果表明，随着 Na 被 Fe 取代，Fe2+ 浓度和 Fe 周围的平均磷数都会增加；而 Fe 周围的平均氧数则会减少。Fe2+ 离子主要是四配位离子，而 Fe3+ 离子主要是五配位离子。此外，Fe 含量的增加会导致 Al/P-O-P 链接逐渐被 Fe2+-O-P 链接取代，从而提高玻璃的化学耐久性。
{"title":"Oxidation states and structural role of iron in sodium iron aluminophosphate glass: A combined study of XAFS experiments and MD simulations","authors":"Hailong Dong , Fangling Jiang , Min Qian , Tianfeng Xue , Sijun Fan , Minzhi Ruan , Zhongdi Li , Shubin Chen , Lu Deng","doi":"10.1016/j.jnoncrysol.2024.123303","DOIUrl":"10.1016/j.jnoncrysol.2024.123303","url":null,"abstract":"<div><div>Vitrification has gained global recognition as one of the most mature techniques for solidification of high-level nuclear waste, and borosilicate glass has been widely used in various countries as the base material. However, iron aluminophosphate glass also found advantages in solidify waste forms containing high concentrations of Zr, Mo and rare earth elements. In this work, oxidation states of Fe and its structural role of sodium iron aluminophosphate glass have been investigated using X-ray absorption fine structure spectroscopy experiments and molecular dynamic simulations. Results show that both the Fe<sup>2+</sup> concentration and the average phosphorus number around Fe increase with the replacement of Na by Fe; whereas, the average oxygen number around Fe decreases. Fe<sup>2+</sup> ions are mainly four-coordinated, and Fe<sup>3+</sup> ions are mainly five-coordinated. Moreover, additional Fe content leads to the gradual replacement of Al/P–O–P linkages by Fe<sup>2+</sup>–O–P linkages, resulting in the enhancement of the chemical durability of the glass.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"647 ","pages":"Article 123303"},"PeriodicalIF":3.2,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142577759","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}
Pub Date : 2024-11-02DOI: 10.1016/j.jnoncrysol.2024.123298
Ondrej Gedeon , Jana Houdkova , Petr Jiricek
The surface and subsurface of commercial barium glassware were studied. The glass was exposed to water and annealing conditions. The decomposed oxygen peak shows the presence of hydrogen bonds to oxygen. Comparison of the amount of OH bonds obtained from oxygen peak decomposition with the amount obtained by the model on the basis of the charge balance shows a discrepancy, which is explained by the oversimplification of the model, which assumes the ideality of the glass structure. The results show that the silica subnetwork in the subsurface region is stable under the conditions used in the experiments. The amount of oxygen is kept constant during water leaching/annealing experiments, but oxygen can change among non-bridging oxygen, dangling/defect oxygen (DO) or H2O/OH states according to the conditions under which the glass is exposed. Alkalis migrating into the alkali-depleted area during annealing prefer to replace hydrogen rather than bind to DO.
对商用钡玻璃器皿的表面和亚表面进行了研究。玻璃暴露在水和退火条件下。分解的氧峰显示了氧氢键的存在。将氧峰值分解得到的氢键数量与根据电荷平衡模型得到的氢键数量进行比较，发现两者之间存在差异，原因是模型过于简化，假定玻璃结构具有理想性。结果表明，在实验条件下，次表层区域的二氧化硅子网络是稳定的。在水浸出/退火实验中，氧气的数量保持不变，但氧气会根据玻璃的暴露条件在非桥接氧、悬浮氧/缺陷氧 (DO) 或 H2O/OH 状态之间发生变化。退火过程中迁移到碱耗尽区域的碱更倾向于取代氢，而不是与 DO 结合。
{"title":"Surface of silicate glass exposed to water","authors":"Ondrej Gedeon , Jana Houdkova , Petr Jiricek","doi":"10.1016/j.jnoncrysol.2024.123298","DOIUrl":"10.1016/j.jnoncrysol.2024.123298","url":null,"abstract":"<div><div>The surface and subsurface of commercial barium glassware were studied. The glass was exposed to water and annealing conditions. The decomposed oxygen peak shows the presence of hydrogen bonds to oxygen. Comparison of the amount of OH bonds obtained from oxygen peak decomposition with the amount obtained by the model on the basis of the charge balance shows a discrepancy, which is explained by the oversimplification of the model, which assumes the ideality of the glass structure. The results show that the silica subnetwork in the subsurface region is stable under the conditions used in the experiments. The amount of oxygen is kept constant during water leaching/annealing experiments, but oxygen can change among non-bridging oxygen, dangling/defect oxygen (DO) or H<sub>2</sub>O/OH states according to the conditions under which the glass is exposed. Alkalis migrating into the alkali-depleted area during annealing prefer to replace hydrogen rather than bind to DO.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"647 ","pages":"Article 123298"},"PeriodicalIF":3.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571666","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}
Pub Date : 2024-11-02DOI: 10.1016/j.jnoncrysol.2024.123300
Yun-Li Li , Wen-Ping Wu , Daniel Şopu , Jürgen Eckert
Molecular dynamics (MD) simulations were performed to study the shock-induced plastic deformation and spallation failure of Cu/Cu64Zr36 crystalline/amorphous composites with a pre-existing void. The results show that the pre-existing void collapses always perpendicular to the direction of the shock loading, regardless of whether the shock direction starts from the crystalline phase or the amorphous phase. The Cu/Cu64Zr36 composites are more prone to spallation failure when the shock starts from the Cu crystalline phase. The changes of dislocation density and shear transformation zone (STZ) activation are closely related to the magnitude and direction of shock velocity. When the shock velocity reaches 2.0 km/s, dislocations in the crystalline phase disappear, dislocation density is close to zero and STZs activate throughout the entire amorphous phase. In addition, regardless of the shock velocity and direction, no shear bands are generated in the Cu/Cu64Zr36 composites under shock loading, which is significantly different from the case of tensile loading.
{"title":"Molecular dynamics simulation of shock-induced plastic deformation and spallation behavior of Cu/Cu64Zr36 crystalline/amorphous composites","authors":"Yun-Li Li , Wen-Ping Wu , Daniel Şopu , Jürgen Eckert","doi":"10.1016/j.jnoncrysol.2024.123300","DOIUrl":"10.1016/j.jnoncrysol.2024.123300","url":null,"abstract":"<div><div>Molecular dynamics (MD) simulations were performed to study the shock-induced plastic deformation and spallation failure of Cu/Cu<sub>64</sub>Zr<sub>36</sub> crystalline/amorphous composites with a pre-existing void. The results show that the pre-existing void collapses always perpendicular to the direction of the shock loading, regardless of whether the shock direction starts from the crystalline phase or the amorphous phase. The Cu/Cu<sub>64</sub>Zr<sub>36</sub> composites are more prone to spallation failure when the shock starts from the Cu crystalline phase. The changes of dislocation density and shear transformation zone (STZ) activation are closely related to the magnitude and direction of shock velocity. When the shock velocity reaches 2.0 km/s, dislocations in the crystalline phase disappear, dislocation density is close to zero and STZs activate throughout the entire amorphous phase. In addition, regardless of the shock velocity and direction, no shear bands are generated in the Cu/Cu<sub>64</sub>Zr<sub>36</sub> composites under shock loading, which is significantly different from the case of tensile loading.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"647 ","pages":"Article 123300"},"PeriodicalIF":3.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571664","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}
Pub Date : 2024-11-02DOI: 10.1016/j.jnoncrysol.2024.123279
Jean-Pierre Crine
Applying Eyring equation to experimental data for the α relaxation of glassy dielectrics shows the fundamental role of the activation entropy in the relaxation dynamics. The combination of Eyring equation and compensation law gives access to other important parameters, such as the compensation temperature and the absolute value of the configurational activation entropy, ΔSC, in the Arrhenius regime. The non linear behavior observed at low temperatures is explained by the time and temperature variation of the configurational activation entropy. We propose that this change corresponds to the rarefaction of free equilibrium states as T is lowered. A simple method is proposed to calculate ΔSC from the change of free energy in the non linear regime. The lowest temperature limit of the a relaxation is not known but it seems unlikely that it would be the VTF or the Kauzmann temperatures. Brief comments on the physical significance of these two parameters are made. It is also shown that relaxation times are not invariant, as sometime suggested
将艾林方程应用于玻璃电介质α弛豫的实验数据显示了活化熵在弛豫动力学中的基本作用。结合艾林方程和补偿定律，可以获得其他重要参数，如阿伦尼乌斯体系中的补偿温度和构型活化熵 ΔSC 的绝对值。在低温下观察到的非线性行为可以用构型活化熵的时间和温度变化来解释。我们认为这种变化与 T 值降低时自由平衡态的稀释相对应。我们提出了一种简单的方法，通过非线性机制中自由能的变化来计算 ΔSC。弛豫的最低温度极限尚不清楚，但似乎不太可能是 VTF 或考兹曼温度。本文对这两个参数的物理意义进行了简要评述。研究还表明，弛豫时间并不像某些人认为的那样是不变的。
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Pub Date : 2024-11-02DOI: 10.1016/j.jnoncrysol.2024.123297
Bo Wang , Zihao Pan , Ziyan Zhao , Bo Zhou , Xuejian Liu , Zhengren Huang , Yan Liu
In this paper, we designed two series of the ZnO-B2O3-SiO2 (ZBS) glass to explore their applicability for joining AlN ceramic. The density, flexural strength, structure, characteristic temperature, coefficient of thermal expansion (CTE) and crystallization behavior of the ZBS glass with varying ZnO and B2O3 content were systematically studied. The results show that as B2O3 content increase, the glass network is disrupted with the transition from three-dimensional shelf-like structure [BO4] to two-dimensional layers [BO3], increasing the number of the broken bonds, while an increase in ZnO results in a more compact glass network structure. We also found that both glass transition temperature (Tg) and softening temperature (TS) exhibit a declining trend with the increase in B2O3 and ZnO. Zn2SiO4 and ZnAl2O4, began to precipitate after heat treatments in all the samples except 60ZnO-30B2O3–10SiO2 (abbreviated as B30), where the diffraction peaks do not appear in Zn2SiO4 but in Zn4B6O13. Notably, Zn2SiO4 is the main phase for most samples while the main phase of B30 sample is ZnAl2O4. The CTE increases from 4.6 to 5.03 (× 10–6/ °C) and 4.23 to 4.73 (× 10–6/ °C) with an increase of B2O3 and ZnO content, respectively. Among these, the CTE of B30 sample is compatible with that of AlN ceramic substrate. The optimal shear strength, 60.32±10.26 MPa, was achieved with B30 samples at 750 °C. The high strength was attributed to the interfacial reaction that leads to strong chemical bonding and the uniform distribution of the ZnAl2O4 in the interlayer, which reinforces the strength of the interlayer itself.
{"title":"Investigation of ZnO-B2O3-SiO2 glass and its application for joining AlN ceramic","authors":"Bo Wang , Zihao Pan , Ziyan Zhao , Bo Zhou , Xuejian Liu , Zhengren Huang , Yan Liu","doi":"10.1016/j.jnoncrysol.2024.123297","DOIUrl":"10.1016/j.jnoncrysol.2024.123297","url":null,"abstract":"<div><div>In this paper, we designed two series of the ZnO-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> (ZBS) glass to explore their applicability for joining AlN ceramic. The density, flexural strength, structure, characteristic temperature, coefficient of thermal expansion (CTE) and crystallization behavior of the ZBS glass with varying ZnO and B<sub>2</sub>O<sub>3</sub> content were systematically studied. The results show that as B<sub>2</sub>O<sub>3</sub> content increase, the glass network is disrupted with the transition from three-dimensional shelf-like structure [BO<sub>4</sub>] to two-dimensional layers [BO<sub>3</sub>], increasing the number of the broken bonds, while an increase in ZnO results in a more compact glass network structure. We also found that both glass transition temperature (T<sub>g</sub>) and softening temperature (T<sub>S</sub>) exhibit a declining trend with the increase in B<sub>2</sub>O<sub>3</sub> and ZnO. Zn<sub>2</sub>SiO<sub>4</sub> and ZnAl<sub>2</sub>O<sub>4</sub>, began to precipitate after heat treatments in all the samples except 60ZnO-30B<sub>2</sub>O<sub>3</sub>–10SiO<sub>2</sub> (abbreviated as B30), where the diffraction peaks do not appear in Zn<sub>2</sub>SiO<sub>4</sub> but in Zn<sub>4</sub>B<sub>6</sub>O<sub>13</sub>. Notably, Zn<sub>2</sub>SiO<sub>4</sub> is the main phase for most samples while the main phase of B30 sample is ZnAl<sub>2</sub>O<sub>4</sub>. The CTE increases from 4.6 to 5.03 (× 10<sup>–6</sup>/ °C) and 4.23 to 4.73 (× 10<sup>–6</sup>/ °C) with an increase of B<sub>2</sub>O<sub>3</sub> and ZnO content, respectively. Among these, the CTE of B30 sample is compatible with that of AlN ceramic substrate. The optimal shear strength, 60.32±10.26 MPa, was achieved with B30 samples at 750 °C. The high strength was attributed to the interfacial reaction that leads to strong chemical bonding and the uniform distribution of the ZnAl<sub>2</sub>O<sub>4</sub> in the interlayer, which reinforces the strength of the interlayer itself.</div></div>","PeriodicalId":16461,"journal":{"name":"Journal of Non-crystalline Solids","volume":"647 ","pages":"Article 123297"},"PeriodicalIF":3.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571667","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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