Geopolymer concrete is gaining recognition as an environmentally friendly alternative to traditional cement-based materials, offering potential solutions for reducing the carbon emissions of the construction industry. This study aims to develop GGBFS–FNS geopolymers utilising ferronickel slag (FNS) and ground-granulated blast-furnace slag (GGBFS). Ground FNS (GFNS) is a potential candidate for replacing fly ash in geopolymers. This research aims to develop for the first time a GGBFS–FNS alkali-activated concrete. Numerous trials were conducted including different GGBFS–FNS blend percentages, several chemical admixtures and varying activator concentrations to develop the optimal binder mix composition. The effects of different chemical admixtures on the properties of geopolymer pastes, mortars, and concretes were investigated. The study evaluated setting time, compressive strength, shrinkage, and physical and durability properties. The results indicate that conventional admixtures have limited impact on the setting time, while increasing the water/solid ratio and decreasing the GGBFS content could extend the initial and final setting times. The presence of FNS aggregate could improve the compressive strength of geopolymer mortars. The water absorber admixture was highly effective in reducing shrinkage and increasing chloride diffusion resistance. The geopolymer mix containing 50 wt.% GFNS and 50 wt.% GGBFS with the presence of the water absorber admixture presented high chloride diffusion resistance, non-reactivity to the alkali–silica reaction and high sulphate resistance. Overall, the GGBFS–FNS geopolymers exhibited promising potential for engineering applications as an environmentally friendly material, particularly in aggressive environments.
{"title":"Developing Geopolymer Concrete by Using Ferronickel Slag and Ground-Granulated Blast-Furnace Slag","authors":"Q. D. Nguyen, Arnaud Castel","doi":"10.3390/ceramics6030114","DOIUrl":"https://doi.org/10.3390/ceramics6030114","url":null,"abstract":"Geopolymer concrete is gaining recognition as an environmentally friendly alternative to traditional cement-based materials, offering potential solutions for reducing the carbon emissions of the construction industry. This study aims to develop GGBFS–FNS geopolymers utilising ferronickel slag (FNS) and ground-granulated blast-furnace slag (GGBFS). Ground FNS (GFNS) is a potential candidate for replacing fly ash in geopolymers. This research aims to develop for the first time a GGBFS–FNS alkali-activated concrete. Numerous trials were conducted including different GGBFS–FNS blend percentages, several chemical admixtures and varying activator concentrations to develop the optimal binder mix composition. The effects of different chemical admixtures on the properties of geopolymer pastes, mortars, and concretes were investigated. The study evaluated setting time, compressive strength, shrinkage, and physical and durability properties. The results indicate that conventional admixtures have limited impact on the setting time, while increasing the water/solid ratio and decreasing the GGBFS content could extend the initial and final setting times. The presence of FNS aggregate could improve the compressive strength of geopolymer mortars. The water absorber admixture was highly effective in reducing shrinkage and increasing chloride diffusion resistance. The geopolymer mix containing 50 wt.% GFNS and 50 wt.% GGBFS with the presence of the water absorber admixture presented high chloride diffusion resistance, non-reactivity to the alkali–silica reaction and high sulphate resistance. Overall, the GGBFS–FNS geopolymers exhibited promising potential for engineering applications as an environmentally friendly material, particularly in aggressive environments.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48708612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cermet films consisting of Ni, BaCe0.4Zr0.4Y0.2O3−δ (BCZY), and Gd0.1Ce0.9Ox (GDC), specifically, 60 wt%Ni–BCZY, 60 wt%Ni–BCZY–GDC, and 60 wt%Ni–GDC, were formed on BCZY electrolyte supports as anodes of proton ceramic fuel cells (PCFCs). The Ni grain size in these films after sintering at 1450 °C was around 2 μm. The GDC addition did not affect the Ni grain size in the case of the BCZY matrix. The anodic properties greatly depended on the oxide phase composition and worsened with increasing the GDC content. This probably occurred because of the addition of GDC, which has low proton conductivity and inhibited the proton conduction path of BCZY, reducing three-phase boundaries in the anode bulk. Since BCZY has a lower grain growth rate during sintering than BaCe0.8Y0.2O3−δ, the Ni grain growth was likely suppressed by the surrounding Ni grains containing small BCZY grains.
{"title":"Anodic Performance of Ni–BCZY and Ni–BCZY–GDC Films on BCZY Electrolytes","authors":"Yoshiteru Itagaki, Yota Kumamoto, Susumu Okayama, Hiromichi Aono","doi":"10.3390/ceramics6030113","DOIUrl":"https://doi.org/10.3390/ceramics6030113","url":null,"abstract":"Cermet films consisting of Ni, BaCe0.4Zr0.4Y0.2O3−δ (BCZY), and Gd0.1Ce0.9Ox (GDC), specifically, 60 wt%Ni–BCZY, 60 wt%Ni–BCZY–GDC, and 60 wt%Ni–GDC, were formed on BCZY electrolyte supports as anodes of proton ceramic fuel cells (PCFCs). The Ni grain size in these films after sintering at 1450 °C was around 2 μm. The GDC addition did not affect the Ni grain size in the case of the BCZY matrix. The anodic properties greatly depended on the oxide phase composition and worsened with increasing the GDC content. This probably occurred because of the addition of GDC, which has low proton conductivity and inhibited the proton conduction path of BCZY, reducing three-phase boundaries in the anode bulk. Since BCZY has a lower grain growth rate during sintering than BaCe0.8Y0.2O3−δ, the Ni grain growth was likely suppressed by the surrounding Ni grains containing small BCZY grains.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47925403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Volkov, E. Glazunova, L. Shilkina, Aleksandr V. Nazarenko, A. Pavelko, Vyacheslav A. Bobylev, L. Reznichenko, I. A. Verbenko
This paper investigates the processes of phase formation of solid solutions of (1 − x)BaTi0.85Zr0.15O3 − xAgNbO3 where x = 0, 0.03, 0.06, 0.09. The optimal temperatures of synthesis and sintering are determined. From the results of X-ray diffraction analysis, it follows that all solid solutions have a perovskite-type structure. Analysis of the microstructure showed that the average grain size decreases at concentrations x = 0.03 and 0.06. Correlations between the cationic composition and dielectric characteristics of the studied solid solutions have been established. The values of the total stored energy and efficiency are determined. The maximum stored energy was found for a solid solution with x = 0.03 and amounted to 0.074 J∙cm−3 with an efficiency of 76.5%.
{"title":"Phase Formation and Properties of Multicomponent Solid Solutions Based on Ba(Ti, Zr)O3 and AgNbO3 for Environmentally Friendly High-Efficiency Energy Storage","authors":"D. Volkov, E. Glazunova, L. Shilkina, Aleksandr V. Nazarenko, A. Pavelko, Vyacheslav A. Bobylev, L. Reznichenko, I. A. Verbenko","doi":"10.3390/ceramics6030112","DOIUrl":"https://doi.org/10.3390/ceramics6030112","url":null,"abstract":"This paper investigates the processes of phase formation of solid solutions of (1 − x)BaTi0.85Zr0.15O3 − xAgNbO3 where x = 0, 0.03, 0.06, 0.09. The optimal temperatures of synthesis and sintering are determined. From the results of X-ray diffraction analysis, it follows that all solid solutions have a perovskite-type structure. Analysis of the microstructure showed that the average grain size decreases at concentrations x = 0.03 and 0.06. Correlations between the cationic composition and dielectric characteristics of the studied solid solutions have been established. The values of the total stored energy and efficiency are determined. The maximum stored energy was found for a solid solution with x = 0.03 and amounted to 0.074 J∙cm−3 with an efficiency of 76.5%.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44742099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Bailey, E. Johnstone, M. Stennett, C. Corkhill, N. Hyatt
99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing.
{"title":"An Investigation of Iodovanadinite Wasteforms for the Immobilisation of Radio-Iodine and Technetium","authors":"D. Bailey, E. Johnstone, M. Stennett, C. Corkhill, N. Hyatt","doi":"10.3390/ceramics6030111","DOIUrl":"https://doi.org/10.3390/ceramics6030111","url":null,"abstract":"99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48679773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Complex inorganic powders based on calcium phosphates have found a plethora of practical applications. Of particular interest are the CaO-P2O5 system-based multi-component material powders and granules as the source of major- and micronutrients for the plants. The emerging strategy is to use nano fertilizers based on hydroxyapatite (HAP) for phosphorus and other nutrient delivery. The doping of micronutrients into HAP structure presents an interesting challenge in obtaining specific phase compositions of these calcium phosphates. Various techniques, including mechanochemical synthesis, have been employed to fabricate doped HAP. Mechanochemical synthesis is of particular interest in this review since it presents a relatively simple, scalable, and cost-effective method of calcium phosphate powder processing. The method involves the use of mechanical force to promote chemical reactions and create nanometric powders. This technique has been successfully applied to produce HAP nanoparticles alone, and HAP doped with other elements, such as zinc and magnesium. Nanofertilizers developed through mechanochemical synthesis can offer several advantages over conventional fertilizers. Their nanoscale size allows for rapid absorption and controlled release of nutrients, which leads to improved nutrient uptake efficiency by plants. Furthermore, the tailored properties of HAP-based nano fertilizers, such as controlled porosity and degradation levels, contribute to their effectiveness in providing plant nutrition.
{"title":"Nutrient-Doped Hydroxyapatite: Structure, Synthesis and Properties","authors":"Mohamed M. Ammar, Sherif Ashraf, J. Baltrusaitis","doi":"10.3390/ceramics6030110","DOIUrl":"https://doi.org/10.3390/ceramics6030110","url":null,"abstract":"Complex inorganic powders based on calcium phosphates have found a plethora of practical applications. Of particular interest are the CaO-P2O5 system-based multi-component material powders and granules as the source of major- and micronutrients for the plants. The emerging strategy is to use nano fertilizers based on hydroxyapatite (HAP) for phosphorus and other nutrient delivery. The doping of micronutrients into HAP structure presents an interesting challenge in obtaining specific phase compositions of these calcium phosphates. Various techniques, including mechanochemical synthesis, have been employed to fabricate doped HAP. Mechanochemical synthesis is of particular interest in this review since it presents a relatively simple, scalable, and cost-effective method of calcium phosphate powder processing. The method involves the use of mechanical force to promote chemical reactions and create nanometric powders. This technique has been successfully applied to produce HAP nanoparticles alone, and HAP doped with other elements, such as zinc and magnesium. Nanofertilizers developed through mechanochemical synthesis can offer several advantages over conventional fertilizers. Their nanoscale size allows for rapid absorption and controlled release of nutrients, which leads to improved nutrient uptake efficiency by plants. Furthermore, the tailored properties of HAP-based nano fertilizers, such as controlled porosity and degradation levels, contribute to their effectiveness in providing plant nutrition.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44344991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present work, the influence of alkali ions (Li, Na, K) on the structural and spectroscopic properties of silica glasses doped with Sm3+ was investigated. Infrared and Raman spectroscopy techniques were used to investigate the structural properties of the alkali silicate glasses. The optical absorption showed bands characteristic of Sm3+ ions in alkali silicate glasses, and this was investigated. The Judd–Ofelt theory was applied to evaluate the phenomenological intensity parameters (Ω2, Ω4, and Ω6) of the optical absorption measurements. The multi-channel visible and near infrared emission transitions originating from the 4G5/2-emitting state of the Sm3+ in alkali silicate glasses with a maximum phonon energy of ~1050 cm−1 were investigated. From the evaluated Judd–Ofelt parameters, radiative parameters such as spontaneous emission probabilities, radiative lifetimes, branching ratios, and stimulated emission cross-sections were calculated. The recorded luminescence spectra regions revealed intense green, orange, red, and near-infrared emission bands, providing new traces for developing tunable laser and optoelectronic devices.
{"title":"Influence of Alkali Metal Ions on the Structural and Spectroscopic Properties of Sm3+-Doped Silicate Glasses","authors":"Israel R. Montoya Matos","doi":"10.3390/ceramics6030109","DOIUrl":"https://doi.org/10.3390/ceramics6030109","url":null,"abstract":"In the present work, the influence of alkali ions (Li, Na, K) on the structural and spectroscopic properties of silica glasses doped with Sm3+ was investigated. Infrared and Raman spectroscopy techniques were used to investigate the structural properties of the alkali silicate glasses. The optical absorption showed bands characteristic of Sm3+ ions in alkali silicate glasses, and this was investigated. The Judd–Ofelt theory was applied to evaluate the phenomenological intensity parameters (Ω2, Ω4, and Ω6) of the optical absorption measurements. The multi-channel visible and near infrared emission transitions originating from the 4G5/2-emitting state of the Sm3+ in alkali silicate glasses with a maximum phonon energy of ~1050 cm−1 were investigated. From the evaluated Judd–Ofelt parameters, radiative parameters such as spontaneous emission probabilities, radiative lifetimes, branching ratios, and stimulated emission cross-sections were calculated. The recorded luminescence spectra regions revealed intense green, orange, red, and near-infrared emission bands, providing new traces for developing tunable laser and optoelectronic devices.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42838364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Boughriet, O. Allahdin, N. Poumaye, Gildas Doyemet, G. Tricot, B. Revel, B. Ouddane, M. Wartel
In recent works, many industrial by-products were employed as solid precursors for the synthesis of alkali-activated binders and as alternatives to Portland cement for the immobilization of hazardous, toxic and nuclear wastes. Among industrial wastes, alkali-activated brick was found to be an interesting porous composite for removing very toxic heavy metals (Pb2+, Cd2+, Co2+) and radio-nuclides (Sr2+, Cs+, Rb+) from aqueous solutions. The starting material is very attractive due to the presence of metakaolinite as a geo-polymer precursor and silica for increasing material permeability and facilitating water filtration. The alkaline reaction gave rise to geo-polymerization followed by partial zeolitization. Elemental surface micro-analysis was performed by Scanning Electron Microscopy (SEM) equipped with an Energy-Dispersive X-ray Spectrometer (EDS). The formation of crystalline phases was corroborated by X-ray diffraction (XRD) analysis. Information about 29Si, 27Al and 1H nuclei environments in crystallized and amorphous aluminosilicates was obtained by 29Si, 27Al and 1H MAS NMR. 27Al–1H dipolar-mediated correlations were investigated by employing dipolar hetero-nuclear multiple quantum coherence (D-HMQC) NMR, highlighting Al–O–H bonds in bridging hydroxyl groups (Si–OH–Al) that are at the origin of adsorptive properties. Aqueous structural stability and cationic immobilization characteristics before and after material calcination were investigated from acid-leaching experiments.
在最近的工作中，许多工业副产品被用作合成碱活化粘合剂的固体前体，并作为波特兰水泥的替代品，用于固定危险、有毒和核废料。在工业废水中，碱活化砖被发现是一种有趣的多孔复合材料，用于去除水溶液中的毒性重金属(Pb2+， Cd2+， Co2+)和放射性核素(Sr2+， Cs+， Rb+)。由于偏高岭石作为土工聚合物前驱体和二氧化硅的存在，该起始材料非常有吸引力，以增加材料的渗透性和促进水过滤。碱性反应引起地聚反应，随后发生部分沸石化反应。采用扫描电子显微镜(SEM)和能谱仪(EDS)对元素表面进行了微观分析。通过x射线衍射(XRD)分析证实了结晶相的形成。通过29Si、27Al和1H MAS NMR获得了结晶和非晶硅铝酸盐中29Si、27Al和1H核环境的信息。利用偶极异核多重量子相干(D-HMQC) NMR研究了27Al-1H偶极介导的相关性，突出了桥接羟基(Si-OH-Al)上的Al-O-H键是吸附性质的起源。通过酸浸实验研究了材料煅烧前后的水结构稳定性和阳离子固定化特性。
{"title":"Alkali-Activated Brick Aggregates as Industrial Valorized Wastes: Synthesis and Properties","authors":"A. Boughriet, O. Allahdin, N. Poumaye, Gildas Doyemet, G. Tricot, B. Revel, B. Ouddane, M. Wartel","doi":"10.3390/ceramics6030108","DOIUrl":"https://doi.org/10.3390/ceramics6030108","url":null,"abstract":"In recent works, many industrial by-products were employed as solid precursors for the synthesis of alkali-activated binders and as alternatives to Portland cement for the immobilization of hazardous, toxic and nuclear wastes. Among industrial wastes, alkali-activated brick was found to be an interesting porous composite for removing very toxic heavy metals (Pb2+, Cd2+, Co2+) and radio-nuclides (Sr2+, Cs+, Rb+) from aqueous solutions. The starting material is very attractive due to the presence of metakaolinite as a geo-polymer precursor and silica for increasing material permeability and facilitating water filtration. The alkaline reaction gave rise to geo-polymerization followed by partial zeolitization. Elemental surface micro-analysis was performed by Scanning Electron Microscopy (SEM) equipped with an Energy-Dispersive X-ray Spectrometer (EDS). The formation of crystalline phases was corroborated by X-ray diffraction (XRD) analysis. Information about 29Si, 27Al and 1H nuclei environments in crystallized and amorphous aluminosilicates was obtained by 29Si, 27Al and 1H MAS NMR. 27Al–1H dipolar-mediated correlations were investigated by employing dipolar hetero-nuclear multiple quantum coherence (D-HMQC) NMR, highlighting Al–O–H bonds in bridging hydroxyl groups (Si–OH–Al) that are at the origin of adsorptive properties. Aqueous structural stability and cationic immobilization characteristics before and after material calcination were investigated from acid-leaching experiments.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47353363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article summarizes the state of the art in increasing antimicrobial activity and hydrophobic properties of geopolymer materials. Geopolymers are inorganic polymers formed by polycondensation of aluminosilicate precursors in an alkaline environment and are considered a viable alternative to ordinary Portland cement-based materials, due to their improved mechanical properties, resistance to chemicals, resistance to high temperature, and lower carbon footprint. Like concrete, they are susceptible to microbially induced deterioration (corrosion), especially in a humid environment, primarily due to surface colonization by sulphur-oxidizing bacteria. This paper reviews various methods for hydrophobic or antimicrobial protection by the method of critical analysis of the literature and the results are discussed, along with potential applications of geopolymers with improved antimicrobial properties. Metal nanoparticles, despite their risks, along with PDMS and epoxy coatings, are the most investigated and effective materials for geopolymer protection. Additionally, future prospects, risks, and challenges for geopolymer research and protection against degradation are presented and discussed.
{"title":"Geopolymer Antimicrobial and Hydrophobic Modifications: A Review","authors":"Vojtěch Růžek, J. Novosád, K. Buczkowska","doi":"10.3390/ceramics6030107","DOIUrl":"https://doi.org/10.3390/ceramics6030107","url":null,"abstract":"The article summarizes the state of the art in increasing antimicrobial activity and hydrophobic properties of geopolymer materials. Geopolymers are inorganic polymers formed by polycondensation of aluminosilicate precursors in an alkaline environment and are considered a viable alternative to ordinary Portland cement-based materials, due to their improved mechanical properties, resistance to chemicals, resistance to high temperature, and lower carbon footprint. Like concrete, they are susceptible to microbially induced deterioration (corrosion), especially in a humid environment, primarily due to surface colonization by sulphur-oxidizing bacteria. This paper reviews various methods for hydrophobic or antimicrobial protection by the method of critical analysis of the literature and the results are discussed, along with potential applications of geopolymers with improved antimicrobial properties. Metal nanoparticles, despite their risks, along with PDMS and epoxy coatings, are the most investigated and effective materials for geopolymer protection. Additionally, future prospects, risks, and challenges for geopolymer research and protection against degradation are presented and discussed.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41841226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Boldyrev, Eugene I. Sitalo, L. A. Shilkina, A. Nazarenko, A. Ushakov, V. Shur, L. Reznichenko, E. Glazunova
Ceramics of the quasi-binary concentration section (0.1 ≤ x ≤ 0.2, Δx = 0.025) of the ternary solid solution system (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 were prepared by the conventional solid-phase reaction method. An X-ray study at different temperatures revealed that (0.5 − x)BF-0.5PFN-xPT ceramics have a cluster morphology. Clusters have different modulation, crystal lattice symmetry, and chemical composition. The presence of a cluster structure in a solid solution with heterovalent substitution, consisting of regions rich in Ti+4, Nb+5, or Fe3+, has led to the appearance of Maxwell–Wagner polarization in the studied ceramics. The study of the dielectric characteristics revealed the relaxor-like behavior of the studied ceramics. The grain morphology, dielectric, pyroelectric, and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient, d33 = 280 pC/N, was obtained in the 0.3BiFeO3-0.5PbFe0.5Nb0.5O3-0.2PbTiO3 ceramics. Study of the dielectric characteristics of all samples revealed relaxor ferroelectric behavior and a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 140–170 °C.
{"title":"Structure and Relaxor Behavior of (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 Ternary Ceramics","authors":"N. Boldyrev, Eugene I. Sitalo, L. A. Shilkina, A. Nazarenko, A. Ushakov, V. Shur, L. Reznichenko, E. Glazunova","doi":"10.3390/ceramics6030106","DOIUrl":"https://doi.org/10.3390/ceramics6030106","url":null,"abstract":"Ceramics of the quasi-binary concentration section (0.1 ≤ x ≤ 0.2, Δx = 0.025) of the ternary solid solution system (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 were prepared by the conventional solid-phase reaction method. An X-ray study at different temperatures revealed that (0.5 − x)BF-0.5PFN-xPT ceramics have a cluster morphology. Clusters have different modulation, crystal lattice symmetry, and chemical composition. The presence of a cluster structure in a solid solution with heterovalent substitution, consisting of regions rich in Ti+4, Nb+5, or Fe3+, has led to the appearance of Maxwell–Wagner polarization in the studied ceramics. The study of the dielectric characteristics revealed the relaxor-like behavior of the studied ceramics. The grain morphology, dielectric, pyroelectric, and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient, d33 = 280 pC/N, was obtained in the 0.3BiFeO3-0.5PbFe0.5Nb0.5O3-0.2PbTiO3 ceramics. Study of the dielectric characteristics of all samples revealed relaxor ferroelectric behavior and a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 140–170 °C.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45485215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This review outlines the state of the art, processing techniques, and mechanical testing methods of zirconia (ZrO2)-based composites reinforced by carbon nanotubes (CNTs). The use of CNTs as a secondary phase in a zirconia matrix is motivated by their outstanding crack self-healing ability, the possibility to tailor the desired nano-structural properties, and their exceptional wear behavior. Therefore, a detailed investigation into CNT features has been provided. The debate of using the different Vickers indentation fracture toughness equations to estimate the resistance of crack propagation was critically reviewed according to crack characteristics. Finally, this review particularly highlights the exceptional role of ZrO2-based composites as a promising material owing to their outstanding tribo-mechanical properties.
{"title":"Zirconia-Based Ceramics Reinforced by Carbon Nanotubes: A Review with Emphasis on Mechanical Properties","authors":"S. Lamnini, D. Pugliese, F. Baino","doi":"10.3390/ceramics6030105","DOIUrl":"https://doi.org/10.3390/ceramics6030105","url":null,"abstract":"This review outlines the state of the art, processing techniques, and mechanical testing methods of zirconia (ZrO2)-based composites reinforced by carbon nanotubes (CNTs). The use of CNTs as a secondary phase in a zirconia matrix is motivated by their outstanding crack self-healing ability, the possibility to tailor the desired nano-structural properties, and their exceptional wear behavior. Therefore, a detailed investigation into CNT features has been provided. The debate of using the different Vickers indentation fracture toughness equations to estimate the resistance of crack propagation was critically reviewed according to crack characteristics. Finally, this review particularly highlights the exceptional role of ZrO2-based composites as a promising material owing to their outstanding tribo-mechanical properties.","PeriodicalId":33263,"journal":{"name":"Ceramics-Switzerland","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42766995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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