Pub Date : 2024-10-09DOI: 10.1016/j.oceram.2024.100694
Milan Parchovianský , Monika Michálková , Ivana Parchovianská , Beáta Pecušová , Dušan Galusek , Amirhossein Pakseresht
The aim of this study was to explore the effect of different solid phases and varied amounts of polyvinyl alcohol (PVA) on granule size of plasma-sprayable yttria-stabilised zirconia (YSZ) with YSZ whiskers (YSZ/W) and lanthanum cerate (La2Ce2O7, LC) with YSZ whiskers (LC/W) as composite powders. The initial phase of this study involved the preparation and optimization of a YSZ suspension using varying solid loadings of YSZ powder (ranging from 30 to 75 wt%) and PVA serving as both a binder and dispersant. The suspension was subjected to rigorous optimization procedures to meet the required standards. The suspensions were spray dried, and the resulting granulates were examined using SEM to determine their shape and size. The particle size of YSZ granules increased with increasing solid loading of YSZ in the suspension. The optimum amount of dispersant was found to be 1 wt% related to the weight of solid, while the solid loading was 75 wt% of YSZ. In some cases, excessive YSZ solid loading and dispersant impaired the formation of spherical granules. Composite YSZ/W and LC/W granules were also prepared with spherical, lemon, or irregular shapes, with the whiskers embedded in the YSZ or LC powder.
{"title":"Yttria-stabilised zirconia and lanthanum cerate granules with YSZ whiskers prepared by spray drying for thermal barrier coatings","authors":"Milan Parchovianský , Monika Michálková , Ivana Parchovianská , Beáta Pecušová , Dušan Galusek , Amirhossein Pakseresht","doi":"10.1016/j.oceram.2024.100694","DOIUrl":"10.1016/j.oceram.2024.100694","url":null,"abstract":"<div><div>The aim of this study was to explore the effect of different solid phases and varied amounts of polyvinyl alcohol (PVA) on granule size of plasma-sprayable yttria-stabilised zirconia (YSZ) with YSZ whiskers (YSZ/W) and lanthanum cerate (La<sub>2</sub>Ce<sub>2</sub>O<sub>7</sub>, LC) with YSZ whiskers (LC/W) as composite powders. The initial phase of this study involved the preparation and optimization of a YSZ suspension using varying solid loadings of YSZ powder (ranging from 30 to 75 wt%) and PVA serving as both a binder and dispersant. The suspension was subjected to rigorous optimization procedures to meet the required standards. The suspensions were spray dried, and the resulting granulates were examined using SEM to determine their shape and size. The particle size of YSZ granules increased with increasing solid loading of YSZ in the suspension. The optimum amount of dispersant was found to be 1 wt% related to the weight of solid, while the solid loading was 75 wt% of YSZ. In some cases, excessive YSZ solid loading and dispersant impaired the formation of spherical granules. Composite YSZ/W and LC/W granules were also prepared with spherical, lemon, or irregular shapes, with the whiskers embedded in the YSZ or LC powder.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100694"},"PeriodicalIF":2.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.oceram.2024.100693
Lenka Ďaková , Alexandra Kovalčíková , Monika Hrubovčáková , Jana Andrejovská , František Kromka , Ján Dusza
Dense (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C with up to 10 wt % SiC whisker were prepared by spark plasma sintering. The influence of SiCw on the microstructure development, mechanical and tribological properties has been investigated. Nanohardness of HEC and SiCw phases varied between 38 GPa and 40 GPa, and indentation modulus of elasticity was ∼605 GPa. The hardness of the composites increased from 22 GPa to 27 GPa and indentation fracture resistance from 3.55 MPa m1/2 to 4.59 MPa m1/2 with increasing SiCw content. The main toughening mechanisms were crack deflection, crack branching, and crack bridging. The system HEC +5 wt% of SiCw was found to possess the highest bending strength of 623 ± 25 MPa. The composites exhibited similar coefficients of frictions with around 0.3 and wear rates approximately 1.50 × 10−6 mm3/N⋅m at 5 N and 2.66 × 10−6 mm3/N⋅m at 25 N with positive influence of SiC phase on the wear mechanisms.
{"title":"Improved mechanical and tribological properties of (TiZrHfNbTa)C with the addition of silicon carbide whiskers","authors":"Lenka Ďaková , Alexandra Kovalčíková , Monika Hrubovčáková , Jana Andrejovská , František Kromka , Ján Dusza","doi":"10.1016/j.oceram.2024.100693","DOIUrl":"10.1016/j.oceram.2024.100693","url":null,"abstract":"<div><div>Dense (Ti<sub>0.2</sub>Zr<sub>0.2</sub>Hf<sub>0.2</sub>Nb<sub>0.2</sub>Ta<sub>0.2</sub>)C with up to 10 wt % SiC whisker were prepared by spark plasma sintering. The influence of SiC<sub>w</sub> on the microstructure development, mechanical and tribological properties has been investigated. Nanohardness of HEC and SiC<sub>w</sub> phases varied between 38 GPa and 40 GPa, and indentation modulus of elasticity was ∼605 GPa. The hardness of the composites increased from 22 GPa to 27 GPa and indentation fracture resistance from 3.55 MPa m<sup>1/2</sup> to 4.59 MPa m<sup>1/2</sup> with increasing SiC<sub>w</sub> content. The main toughening mechanisms were crack deflection, crack branching, and crack bridging. The system HEC +5 wt% of SiC<sub>w</sub> was found to possess the highest bending strength of 623 ± 25 MPa. The composites exhibited similar coefficients of frictions with around 0.3 and wear rates approximately 1.50 × 10<sup>−6</sup> mm<sup>3</sup>/N⋅m at 5 N and 2.66 × 10<sup>−6</sup> mm<sup>3</sup>/N⋅m at 25 N with positive influence of SiC phase on the wear mechanisms.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100693"},"PeriodicalIF":2.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-02DOI: 10.1016/j.oceram.2024.100692
Sonia Marín-Cortés , Mattia Biesuz , Aida Serrano , Emanuele De Bona , Esther Enríquez , José F. Fernández , Vincenzo M. Sglavo
A ceramic composition containing 95 wt% of construction and demolition waste-like material was consolidated by cold sintering process at 200 °C using KOH water solutions as the liquid medium. The relative density of the samples reaches ∼90 % of the theoretical one for process conditions of 600 MPa and 60 min. A post-annealing process at 1100 °C of the as-cold sintered samples causes a slight increase in the relative density and of their mechanical strength compared with conventionally sintered samples at 1100 °C and increases the shape factor of the Weibull distribution, thus increasing the reliability of the component. It is shown that cold sintering of the material avoids its high pyroplasticity, providing low shrinkage and reducing internal defects in the ceramic. This work represents the first exploration of the viability of manufacturing ceramic tiles with high recycled content contributing to the transition to a greener world.
以 KOH 水溶液为液体介质，在 200 °C 下通过冷烧结工艺固结了含有 95% 建筑和拆除废料类材料的陶瓷组合物。在 600 兆帕和 60 分钟的工艺条件下，样品的相对密度达到理论值的 90%。与传统的 1100 °C 烧结样品相比，在 1100 °C 下对冷烧结样品进行后退火处理可使相对密度和机械强度略有增加，并提高威布尔分布的形状系数，从而提高部件的可靠性。研究表明，材料的冷烧结可避免其较高的热塑性，提供较低的收缩率并减少陶瓷的内部缺陷。这项研究首次探索了制造高回收利用率瓷砖的可行性，有助于向绿色世界过渡。
{"title":"Promoting the circularity of ceramic materials through cold sintering of aggregates from construction and demolition waste","authors":"Sonia Marín-Cortés , Mattia Biesuz , Aida Serrano , Emanuele De Bona , Esther Enríquez , José F. Fernández , Vincenzo M. Sglavo","doi":"10.1016/j.oceram.2024.100692","DOIUrl":"10.1016/j.oceram.2024.100692","url":null,"abstract":"<div><div>A ceramic composition containing 95 wt% of construction and demolition waste-like material was consolidated by cold sintering process at 200 °C using KOH water solutions as the liquid medium. The relative density of the samples reaches ∼90 % of the theoretical one for process conditions of 600 MPa and 60 min. A post-annealing process at 1100 °C of the as-cold sintered samples causes a slight increase in the relative density and of their mechanical strength compared with conventionally sintered samples at 1100 °C and increases the shape factor of the Weibull distribution, thus increasing the reliability of the component. It is shown that cold sintering of the material avoids its high pyroplasticity, providing low shrinkage and reducing internal defects in the ceramic. This work represents the first exploration of the viability of manufacturing ceramic tiles with high recycled content contributing to the transition to a greener world.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100692"},"PeriodicalIF":2.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-02DOI: 10.1016/j.oceram.2024.100691
Md Elias , Ehsanur Rahman , Sonia Akter , Mohammad Awlad Hossain , Rumana A. Jahan , Md Nizam Uddin , Shakhawat H. Firoz
The growing interest in combining the photocatalytic properties of semiconductors like ZnO and TiO2 with the superior electron conduction capabilities of graphene has resulted in the successful synthesis of in-situ reduced graphene oxide (rGO) supported ZnO-TiO2 nanostructures through a simple microwave-assisted synthesis method. X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–visible spectroscopy (UV–vis), and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterize structural, morphological and optical properties as well as surface functional groups of the synthesized products. The XRD measurements of our synthesized samples confirm both structural crystallinity and phase purity, while the FTIR analysis verifies the complete reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The synthesized ternary nanocomposite ZnO-TiO2-rGO exhibited a remarkable 100 % adsorption-assisted removal efficiency for 20 mg/L methylene blue (MB) dye under ultraviolet light illumination within 120 min, along with a 56 % dye adsorption removal efficiency in the same time interval. In comparison, pure ZnO showed 0 % adsorption and only 31 % photocatalytic efficiency at the similar condition. Remarkably, the ZnO-TiO2-rGO nanocomposite exhibited exceptional photocatalytic activity mediated by adsorption, achieving complete degradation of MB dye within 5 min under sunlight irradiation. The photocatalytic efficiency and dye adsorption capacity were found to be significantly lower for the anionic dye methyl orange (MO) compared to the cationic MB dye. The study thoroughly investigated the influence of catalyst dose and initial dye concentration on photodegradation. The proposed mechanism indicates that the extensive surface area and numerous active sites on the rGO promote adsorption, which is then followed by degradation through the metal oxides. Overall, the results unveil that the microwave-assisted synthesis of ZnO-TiO2-rGO nanocomposite is a promising and environmentally friendly approach for efficiently degrading dyes from contaminated wastewater using both UV light and natural sunlight irradiation.
{"title":"Eco-friendly fabrication of ZnO-TiO2-rGO nanocomposite for efficient adsorption-assisted organic dyes elimination","authors":"Md Elias , Ehsanur Rahman , Sonia Akter , Mohammad Awlad Hossain , Rumana A. Jahan , Md Nizam Uddin , Shakhawat H. Firoz","doi":"10.1016/j.oceram.2024.100691","DOIUrl":"10.1016/j.oceram.2024.100691","url":null,"abstract":"<div><div>The growing interest in combining the photocatalytic properties of semiconductors like ZnO and TiO<sub>2</sub> with the superior electron conduction capabilities of graphene has resulted in the successful synthesis of in-situ reduced graphene oxide (rGO) supported ZnO-TiO<sub>2</sub> nanostructures through a simple microwave-assisted synthesis method. X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–visible spectroscopy (UV–vis), and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterize structural, morphological and optical properties as well as surface functional groups of the synthesized products. The XRD measurements of our synthesized samples confirm both structural crystallinity and phase purity, while the FTIR analysis verifies the complete reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The synthesized ternary nanocomposite ZnO-TiO<sub>2</sub>-rGO exhibited a remarkable 100 % adsorption-assisted removal efficiency for 20 mg/L methylene blue (MB) dye under ultraviolet light illumination within 120 min, along with a 56 % dye adsorption removal efficiency in the same time interval. In comparison, pure ZnO showed 0 % adsorption and only 31 % photocatalytic efficiency at the similar condition. Remarkably, the ZnO-TiO<sub>2</sub>-rGO nanocomposite exhibited exceptional photocatalytic activity mediated by adsorption, achieving complete degradation of MB dye within 5 min under sunlight irradiation. The photocatalytic efficiency and dye adsorption capacity were found to be significantly lower for the anionic dye methyl orange (MO) compared to the cationic MB dye. The study thoroughly investigated the influence of catalyst dose and initial dye concentration on photodegradation. The proposed mechanism indicates that the extensive surface area and numerous active sites on the rGO promote adsorption, which is then followed by degradation through the metal oxides. Overall, the results unveil that the microwave-assisted synthesis of ZnO-TiO<sub>2</sub>-rGO nanocomposite is a promising and environmentally friendly approach for efficiently degrading dyes from contaminated wastewater using both UV light and natural sunlight irradiation.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100691"},"PeriodicalIF":2.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.oceram.2024.100690
Francesco Baino , Federico Gaido , Roberta Gabrieli , Dario Alidoost , Alessandro Schiavi , Mehdi Mohammadi , Martin Schwentenwein , Dilshat Tulyaganov , Enrica Verné
The introduction of additive manufacturing technologies in the field of biomaterials science has opened new horizons for regenerative medicine. In this work, we pushed the potential of vat polymerization to the limit for fabricating ultra-porous bioactive SiO2-CaO-MgO-P2O5-CaF2-Na2O glass scaffolds with bone-like architectural characteristics. The tomographic reconstruction of an open-cell foam was used as input file to the printing system and reliably reproduced in all its exquisite details, as assessed by morphological analyses of sintered scaffolds (thickness of single struts 35 μm, exceptionally high porosity around 94 vol%, most pores with size from 500 to 900 μm). Immersion studies in simulated body fluid (SBF) revealed the apatite-forming ability (i.e., in vitro bioactivity) of the scaffolds, the surface of which started being coated by calcium phosphate after just 3 days from the beginning of the experiments. Taken together, these results show great promise for application of such scaffolds in bone defect repair.
{"title":"Vat photopolymerization of ultra-porous bioactive glass foams","authors":"Francesco Baino , Federico Gaido , Roberta Gabrieli , Dario Alidoost , Alessandro Schiavi , Mehdi Mohammadi , Martin Schwentenwein , Dilshat Tulyaganov , Enrica Verné","doi":"10.1016/j.oceram.2024.100690","DOIUrl":"10.1016/j.oceram.2024.100690","url":null,"abstract":"<div><div>The introduction of additive manufacturing technologies in the field of biomaterials science has opened new horizons for regenerative medicine. In this work, we pushed the potential of vat polymerization to the limit for fabricating ultra-porous bioactive SiO<sub>2</sub>-CaO-MgO-P<sub>2</sub>O<sub>5</sub>-CaF<sub>2</sub>-Na<sub>2</sub>O glass scaffolds with bone-like architectural characteristics. The tomographic reconstruction of an open-cell foam was used as input file to the printing system and reliably reproduced in all its exquisite details, as assessed by morphological analyses of sintered scaffolds (thickness of single struts 35 μm, exceptionally high porosity around 94 vol%, most pores with size from 500 to 900 μm). Immersion studies in simulated body fluid (SBF) revealed the apatite-forming ability (i.e., in vitro bioactivity) of the scaffolds, the surface of which started being coated by calcium phosphate after just 3 days from the beginning of the experiments. Taken together, these results show great promise for application of such scaffolds in bone defect repair.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100690"},"PeriodicalIF":2.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.oceram.2024.100689
Ahmed Gamal Abd-Elsatar , Hamada Elsayed , Hana Kanková , Branislav Hruška , Jozef Kraxner , Enrico Bernardo , Dušan Galusek
Pharmaceutical containers for parenteral use, including vials, ampoules, prefilled syringes, and cartridges, are traditionally made of glass. However, the most commonly used type, borosilicate glass, is susceptible to issues such as breakage, corrosion, and delamination, which can jeopardize the safety and efficacy of the enclosed drugs. To address these concerns without compromising the visual or qualitative aspects of borosilicate medical glass vials, this study aimed at the enhancement of their mechanical, chemical, and corrosion resistance. A single ion exchange treatment (IET) in a salt bath of molten KNO3 at temperatures of 400, 450, and 500 °C for 2, 12, and 24 h was applied. The effects of the ion exchange process performed under different conditions were assessed by measuring Vickers hardness, crushing load, and chemical durability. The mechanical load required to crush full-body vials after the ion exchange process at 500 °C for 2, 12, and 24 h showed an increase in the applied force values (1650 ± 80, 2340 ± 80, and 2325 ± 40 N) compared to untreated vials (1157 ± 20 N).
No radial cracks were observed on the surface of treated glass vials after indentation, indicating the presence of compressive stresses that prevented the initiation and propagation of cracks. The EDS analysis confirmed an increase in potassium concentration and a decrease in sodium content near the surface of samples modified by ion exchange treatment. The treated samples showed appropriate chemical stability in different acidic, basic, and neutral solutions. Conspicuous changes are noticed in the Raman spectra after IET, specifically in the Qn species region. The results indicate the potential of the ion exchange treatment in enhancing the properties of borosilicate glass vials by relatively simple and easily scalable techniques.
{"title":"Ion-exchange enhancement of borosilicate glass vials for pharmaceutical packaging","authors":"Ahmed Gamal Abd-Elsatar , Hamada Elsayed , Hana Kanková , Branislav Hruška , Jozef Kraxner , Enrico Bernardo , Dušan Galusek","doi":"10.1016/j.oceram.2024.100689","DOIUrl":"10.1016/j.oceram.2024.100689","url":null,"abstract":"<div><div>Pharmaceutical containers for parenteral use, including vials, ampoules, prefilled syringes, and cartridges, are traditionally made of glass. However, the most commonly used type, borosilicate glass, is susceptible to issues such as breakage, corrosion, and delamination, which can jeopardize the safety and efficacy of the enclosed drugs. To address these concerns without compromising the visual or qualitative aspects of borosilicate medical glass vials, this study aimed at the enhancement of their mechanical, chemical, and corrosion resistance. A single ion exchange treatment (IET) in a salt bath of molten KNO<sub>3</sub> at temperatures of 400, 450, and 500 °C for 2, 12, and 24 h was applied. The effects of the ion exchange process performed under different conditions were assessed by measuring Vickers hardness, crushing load, and chemical durability. The mechanical load required to crush full-body vials after the ion exchange process at 500 °C for 2, 12, and 24 h showed an increase in the applied force values (1650 ± 80, 2340 ± 80, and 2325 ± 40 N) compared to untreated vials (1157 ± 20 N).</div><div>No radial cracks were observed on the surface of treated glass vials after indentation, indicating the presence of compressive stresses that prevented the initiation and propagation of cracks. The EDS analysis confirmed an increase in potassium concentration and a decrease in sodium content near the surface of samples modified by ion exchange treatment. The treated samples showed appropriate chemical stability in different acidic, basic, and neutral solutions. Conspicuous changes are noticed in the Raman spectra after IET, specifically in the Q<sub>n</sub> species region. The results indicate the potential of the ion exchange treatment in enhancing the properties of borosilicate glass vials by relatively simple and easily scalable techniques.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100689"},"PeriodicalIF":2.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polycrystalline Ta2O5 inverse opal (IO) photonic crystal powders were synthesized using PMMA colloidal crystals as sacrificial templates. We prepared Ta2O5 IO powders with vibrant structural colors at UV–vis wavelengths. The photonic bandgaps (PBGs) in the Ta2O5 IO powders red-shifted as a function of both the macropore diameter and the refractive index of the medium filling the macropores. Owing to their polycrystalline structure, the Ta2O5 IO powders exposed PBGs for various FCC facets, making investigation of their optical properties significantly more complex than Ta2O5 IO thin films that preferentially expose only (111) planes as studied previously. Due to the overlap of the PBGs from different FCC facets and the defects that cause light scattering, much of the typical angle-dependent structural color observed in IO thin films was lost in the Ta2O5 IO powders. This study offers new insights into the optical properties of IO powders.
{"title":"Synthesis of polycrystalline Ta₂O₅ inverse opal photonic crystal powders and their optical characterization","authors":"Taiki Maekawa , Hiroyuki Maekawa , Yuto Ikeda , Tomoya Onoe , Geoffrey I.N. Waterhouse , Kei-ichiro Murai , Toshihiro Moriga","doi":"10.1016/j.oceram.2024.100688","DOIUrl":"10.1016/j.oceram.2024.100688","url":null,"abstract":"<div><div>Polycrystalline Ta<sub>2</sub>O<sub>5</sub> inverse opal (IO) photonic crystal powders were synthesized using PMMA colloidal crystals as sacrificial templates. We prepared Ta<sub>2</sub>O<sub>5</sub> IO powders with vibrant structural colors at UV–vis wavelengths. The photonic bandgaps (PBGs) in the Ta<sub>2</sub>O<sub>5</sub> IO powders red-shifted as a function of both the macropore diameter and the refractive index of the medium filling the macropores. Owing to their polycrystalline structure, the Ta<sub>2</sub>O<sub>5</sub> IO powders exposed PBGs for various FCC facets, making investigation of their optical properties significantly more complex than Ta<sub>2</sub>O<sub>5</sub> IO thin films that preferentially expose only (111) planes as studied previously. Due to the overlap of the PBGs from different FCC facets and the defects that cause light scattering, much of the typical angle-dependent structural color observed in IO thin films was lost in the Ta<sub>2</sub>O<sub>5</sub> IO powders. This study offers new insights into the optical properties of IO powders.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100688"},"PeriodicalIF":2.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.oceram.2024.100687
Mohammed Ali M. Rihan , Richard Ocharo Onchiri , Naftary Gathimba , Bernadette Sabuni
Geopolymer or alkali-activated binders are being recognized as an eco-friendly, sustainable substitute for ordinary Portland cement (OPC). The development of high-performance concrete with improved durability and mechanical properties and the addition of environmentally friendly components is a continuous effort. Therefore, the current work examines the durability of fly ash-sugarcane bagasse ash mechanical characteristics in terms of water absorption, exposure to elevated temperatures, and acid resistance. The mechanical properties of the geopolymer concrete (GPC) and OPC concrete specimens were evaluated after being subjected to elevated temperatures of 200 °C, 400 °C, 600 °C, and 800 °C. The acid resistance was determined by submerging the concrete specimens in 3 % sulfuric acid (H2SO4). The acid resistance of the specimens was evaluated through visual inspection, weight variation, and the percentage loss in compressive strength (CR). According to the study, CR typically drops as temperature increases from ambient temperature to 800 °C. However, the rate of decline reduced as temperature increased from ambient temperature to 200 °C. Moreover, the GPC specimens showed a strength loss between 13 % and 21 % following 28 days of sulfuric acid immersion. In contrast, exposure to sulfuric acid caused a 51 % drop in strength for the OPC concrete samples.
{"title":"Assessing the durability performance of geopolymer concrete utilizing fly ash and sugarcane bagasse ash as sustainable binders","authors":"Mohammed Ali M. Rihan , Richard Ocharo Onchiri , Naftary Gathimba , Bernadette Sabuni","doi":"10.1016/j.oceram.2024.100687","DOIUrl":"10.1016/j.oceram.2024.100687","url":null,"abstract":"<div><div>Geopolymer or alkali-activated binders are being recognized as an eco-friendly, sustainable substitute for ordinary Portland cement (OPC). The development of high-performance concrete with improved durability and mechanical properties and the addition of environmentally friendly components is a continuous effort. Therefore, the current work examines the durability of fly ash-sugarcane bagasse ash mechanical characteristics in terms of water absorption, exposure to elevated temperatures, and acid resistance. The mechanical properties of the geopolymer concrete (GPC) and OPC concrete specimens were evaluated after being subjected to elevated temperatures of 200 °C, 400 °C, 600 °C, and 800 °C. The acid resistance was determined by submerging the concrete specimens in 3 % sulfuric acid (H<sub>2</sub>SO<sub>4</sub>). The acid resistance of the specimens was evaluated through visual inspection, weight variation, and the percentage loss in compressive strength (C<sub>R</sub>). According to the study, C<sub>R</sub> typically drops as temperature increases from ambient temperature to 800 °C. However, the rate of decline reduced as temperature increased from ambient temperature to 200 °C. Moreover, the GPC specimens showed a strength loss between 13 % and 21 % following 28 days of sulfuric acid immersion. In contrast, exposure to sulfuric acid caused a 51 % drop in strength for the OPC concrete samples.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100687"},"PeriodicalIF":2.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the influence of different additives on a geopolymer matrix composite (GMC) was explored as an alternative to a ceramic matrix composite (CMC) for thermostructural applications. Different GMCs using an N610 textile (10 × 10 cm2) and various additives (SrCO3, BaCO3, BaSO4, MgO and Al2O3 and mullite-rich powder) were cured under 6 MPa at 120 °C for 2 h. The mechanical, microstructural and structural data of the composites were compared with those of the geopolymer matrix after thermal treatment at 1150 °C. The results showed that the addition of alkali-earth barium carbonate or sulfate to the geopolymer matrix facilitated the formation of alkali-earth aluminosilicate crystalline phases and a higher viscous flow apparition temperature (990 °C), which did not enhance its mechanical properties (50 MPa) due to poor impregnation of the textile. Refractory additives such as MgO and Al2O3 in the geopolymer matrix support fiber impregnation with a low-viscous-flow apparition temperature (865 °C) and the formation of crystalline phases such as forsterite, spinel and sapphirine, which act as reinforcements, allowing a flexural strength up to 80 MPa. The addition of a refractory compound, such as mullite, leads to better embedding of fibers and a flexural strength reaching 100 MPa. To conclude, mixing the geopolymer matrix with refractory compounds results in a successful thermo-structural geopolymer composite.
{"title":"Influences of additives on the properties of geopolymer matrix composites (GMCS) for high-temperature applications (1150 °C)","authors":"Quentin Cligny , Ameni Gharzouni , Patrice Duport , Damien Brandt , Sylvie Rossignol","doi":"10.1016/j.oceram.2024.100685","DOIUrl":"10.1016/j.oceram.2024.100685","url":null,"abstract":"<div><div>In this study, the influence of different additives on a geopolymer matrix composite (GMC) was explored as an alternative to a ceramic matrix composite (CMC) for thermostructural applications. Different GMCs using an N610 textile (10 × 10 cm<sup>2</sup>) and various additives (SrCO<sub>3</sub>, BaCO<sub>3</sub>, BaSO<sub>4</sub>, MgO and Al<sub>2</sub>O<sub>3</sub> and mullite-rich powder) were cured under 6 MPa at 120 °C for 2 h. The mechanical, microstructural and structural data of the composites were compared with those of the geopolymer matrix after thermal treatment at 1150 °C. The results showed that the addition of alkali-earth barium carbonate or sulfate to the geopolymer matrix facilitated the formation of alkali-earth aluminosilicate crystalline phases and a higher viscous flow apparition temperature (990 °C), which did not enhance its mechanical properties (50 MPa) due to poor impregnation of the textile. Refractory additives such as MgO and Al<sub>2</sub>O<sub>3</sub> in the geopolymer matrix support fiber impregnation with a low-viscous-flow apparition temperature (865 °C) and the formation of crystalline phases such as forsterite, spinel and sapphirine, which act as reinforcements, allowing a flexural strength up to 80 MPa. The addition of a refractory compound, such as mullite, leads to better embedding of fibers and a flexural strength reaching 100 MPa. To conclude, mixing the geopolymer matrix with refractory compounds results in a successful thermo-structural geopolymer composite.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100685"},"PeriodicalIF":2.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.oceram.2024.100686
Tim Stötzel , Swantje Funk , Tobias Fey
The presence of pores in a ceramic leads to a lower Young's modulus compared to dense material. For the development of porous ceramics with tailored elastic properties, an exact determination of the Young's modulus is required, especially for industrial applications. Therefore, we investigated the suitability of the non-destructive impulse excitation technique for measuring the dynamic Young's modulus of two-dimensional ceramics with low porosity (P < 19 %). For rectangular samples it was shown that the measurement results depend on the geometric pore position, as added pores outside the nodal lines of the fundamental flexural vibration had no influence on the result. Pores in the inner part of the sample led to a decrease of the Young's modulus that is in good agreement with empirical and analytical models. For the investigated interval of porosity range, the influence of pore size and geometric position on the reduction of the Young's modulus was determined.
{"title":"The sound of porosity: Suitability of the impulse excitation technique (IET) to determine the Young's modulus of 2D macroporous ceramics","authors":"Tim Stötzel , Swantje Funk , Tobias Fey","doi":"10.1016/j.oceram.2024.100686","DOIUrl":"10.1016/j.oceram.2024.100686","url":null,"abstract":"<div><div>The presence of pores in a ceramic leads to a lower Young's modulus compared to dense material. For the development of porous ceramics with tailored elastic properties, an exact determination of the Young's modulus is required, especially for industrial applications. Therefore, we investigated the suitability of the non-destructive impulse excitation technique for measuring the dynamic Young's modulus of two-dimensional ceramics with low porosity (P < 19 %). For rectangular samples it was shown that the measurement results depend on the geometric pore position, as added pores outside the nodal lines of the fundamental flexural vibration had no influence on the result. Pores in the inner part of the sample led to a decrease of the Young's modulus that is in good agreement with empirical and analytical models. For the investigated interval of porosity range, the influence of pore size and geometric position on the reduction of the Young's modulus was determined.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100686"},"PeriodicalIF":2.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001500/pdfft?md5=949bfb5f0a3940870461e6621efc0076&pid=1-s2.0-S2666539524001500-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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