Pub Date : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.245
Qi-Wen Wang , Zhang-Ao Shi , Lin Guo , Wei-Hao Cai , Jia-Min Wu , Chong Tian , Xin Lin , Hai-Sheng Xu , Fen Wang , Yu-Sheng Shi
The preparation of Si3N4 ceramics by vat photopolymerization (VPP) has motivated increasing research interest. However, it is challenging to prepare Si3N4 ceramics by VPP due to the high UV-light absorbance and refractive index of powder. In this paper, a method for Al2O3-coated Si3N4 powder was proposed. Combined with the boehmite-coated and high-temperature treatment, Al2O3 was successfully coated on the surface of Si3N4 powder. The effect of Al2O3 content on the properties of Si3N4 powders, slurry and the sintered Si3N4 samples were investigated. The Al2O3 coating layer not only improves the curing forming ability of Si3N4 slurries, but also can directly act as one of the sintering aids of Si3N4 ceramics. The bulk density of the samples decreases from 3.04 ± 0.02 g/cm3 to 2.97 ± 0.01 g/cm3 with the increase of coating content, while the porosity increases from 5.38 ± 0.89 % to 7.54 ± 0.63 %. The sample of 5 wt % Al2O3 coating content has the maximum flexural strength of 474.28 ± 16.38 MPa and the highest relative density of 94.62 ± 0.89 %. This work can not only obtain a great modification effect, but also promote the dense sintering of Si3N4 ceramics during subsequent stages, which provides a constructive method for modifying Si3N4 powders to achieve photopolymerization.
{"title":"Effect of Al2O3 coating on the properties of Si3N4 ceramics prepared by vat photopolymerization","authors":"Qi-Wen Wang , Zhang-Ao Shi , Lin Guo , Wei-Hao Cai , Jia-Min Wu , Chong Tian , Xin Lin , Hai-Sheng Xu , Fen Wang , Yu-Sheng Shi","doi":"10.1016/j.ceramint.2024.09.245","DOIUrl":"10.1016/j.ceramint.2024.09.245","url":null,"abstract":"<div><div>The preparation of Si<sub>3</sub>N<sub>4</sub> ceramics by vat photopolymerization (VPP) has motivated increasing research interest. However, it is challenging to prepare Si<sub>3</sub>N<sub>4</sub> ceramics by VPP due to the high UV-light absorbance and refractive index of powder. In this paper, a method for Al<sub>2</sub>O<sub>3</sub>-coated Si<sub>3</sub>N<sub>4</sub> powder was proposed. Combined with the boehmite-coated and high-temperature treatment, Al<sub>2</sub>O<sub>3</sub> was successfully coated on the surface of Si<sub>3</sub>N<sub>4</sub> powder. The effect of Al<sub>2</sub>O<sub>3</sub> content on the properties of Si<sub>3</sub>N<sub>4</sub> powders, slurry and the sintered Si<sub>3</sub>N<sub>4</sub> samples were investigated. The Al<sub>2</sub>O<sub>3</sub> coating layer not only improves the curing forming ability of Si<sub>3</sub>N<sub>4</sub> slurries, but also can directly act as one of the sintering aids of Si<sub>3</sub>N<sub>4</sub> ceramics. The bulk density of the samples decreases from 3.04 ± 0.02 g/cm<sup>3</sup> to 2.97 ± 0.01 g/cm<sup>3</sup> with the increase of coating content, while the porosity increases from 5.38 ± 0.89 % to 7.54 ± 0.63 %. The sample of 5 wt % Al<sub>2</sub>O<sub>3</sub> coating content has the maximum flexural strength of 474.28 ± 16.38 MPa and the highest relative density of 94.62 ± 0.89 %. This work can not only obtain a great modification effect, but also promote the dense sintering of Si<sub>3</sub>N<sub>4</sub> ceramics during subsequent stages, which provides a constructive method for modifying Si<sub>3</sub>N<sub>4</sub> powders to achieve photopolymerization.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49041-49050"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.243
Xin Zhao , Jimin Chen , Yong Zeng
BaTiO3/Ca10(PO4)6(OH)2 composite ceramic is an outstanding representative of piezoelectric biomaterials, with excellent biocompatibility and piezoelectric effect, and has potential applications in the field of bone tissue repair. In this work, vat photopolymerization 3D printing technology was used to fabricate triply periodic minimal surface structure BaTiO3/Ca10(PO4)6(OH)2 composite ceramic bone tissue scaffolds with different pore sizes and porosity, and their mechanical and electrical properties were studied. First, the ceramic slurry configuration process was optimized to obtain a ceramic slurry with high solid content (45 vol%) and excellent rheological properties. Then the effect of sintering temperature on microstructure, relative density, mechanical properties, and electrical properties is discussed. The results show that when sintering at 1300 °C, the BaTiO3/Ca10(PO4)6(OH)2 composite ceramic has the highest relative density (99.18 %), the highest compressive strength (44 MPa), large relative dielectric constant (379–389), and low dielectric loss. The polarization electric field strength of the BaTiO3/Ca10(PO4)6(OH)2 composite ceramic was set to 15 kV/cm through the test of the hysteresis loop. Finally, based on multi-physics coupled finite element simulation, the effects of different porosity and different pore sizes on stress distribution and piezoelectric potential were analyzed, and the relationship between them was explored through experiments. The results show that as the porosity increases and the pore size decreases, the mechanical properties of the scaffold decrease significantly, and its compressive strength ranges between 1.67 and 4.26 MPa; as the porosity increases and the pore size increases, the piezoelectric coefficient (d33) of the scaffold showed a decreasing trend, and its d33 ranged between 2 and 9 pC/N. The mechanical and electrical properties of the scaffold meet the performance requirements of cancellous bone. In summary, this work provides a strategy for the application of customized BaTiO3/Ca10(PO4)6(OH)2 composite ceramic scaffolds in new-generation orthopedic implants.
{"title":"Study on performance regulation of electro-mechanical properties 3D printed BaTiO3/HA porous structure composite ceramic","authors":"Xin Zhao , Jimin Chen , Yong Zeng","doi":"10.1016/j.ceramint.2024.09.243","DOIUrl":"10.1016/j.ceramint.2024.09.243","url":null,"abstract":"<div><div>BaTiO<sub>3</sub>/Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub> composite ceramic is an outstanding representative of piezoelectric biomaterials, with excellent biocompatibility and piezoelectric effect, and has potential applications in the field of bone tissue repair. In this work, vat photopolymerization 3D printing technology was used to fabricate triply periodic minimal surface structure BaTiO<sub>3</sub>/Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub> composite ceramic bone tissue scaffolds with different pore sizes and porosity, and their mechanical and electrical properties were studied. First, the ceramic slurry configuration process was optimized to obtain a ceramic slurry with high solid content (45 vol%) and excellent rheological properties. Then the effect of sintering temperature on microstructure, relative density, mechanical properties, and electrical properties is discussed. The results show that when sintering at 1300 °C, the BaTiO<sub>3</sub>/Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub> composite ceramic has the highest relative density (99.18 %), the highest compressive strength (44 MPa), large relative dielectric constant (379–389), and low dielectric loss. The polarization electric field strength of the BaTiO<sub>3</sub>/Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub> composite ceramic was set to 15 kV/cm through the test of the hysteresis loop. Finally, based on multi-physics coupled finite element simulation, the effects of different porosity and different pore sizes on stress distribution and piezoelectric potential were analyzed, and the relationship between them was explored through experiments. The results show that as the porosity increases and the pore size decreases, the mechanical properties of the scaffold decrease significantly, and its compressive strength ranges between 1.67 and 4.26 MPa; as the porosity increases and the pore size increases, the piezoelectric coefficient (<em>d</em><sub><strong><em>33</em></strong></sub>) of the scaffold showed a decreasing trend, and its <em>d</em><sub><strong><em>33</em></strong></sub> ranged between 2 and 9 pC/N. The mechanical and electrical properties of the scaffold meet the performance requirements of cancellous bone. In summary, this work provides a strategy for the application of customized BaTiO<sub>3</sub>/Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>(OH)<sub>2</sub> composite ceramic scaffolds in new-generation orthopedic implants.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49021-49032"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The FeTiO3 nanopowder is a vital engineering material known for its exceptional performance in energy generation, storage, electrochemical sensors, and catalysis. However, synthesizing FeTiO3 nanopowder with high crystallinity and phase purity typically requires specialized equipment and controlled heat treatment due to the instability of Fe2+ ions. Using the one-step solution combustion synthesis (SCS) method, FeTiO3 nanopowder withe high crystallinity were successfully produced utilizing basic equipment. Additionally, the influence of carbon additives on phase transitions, as well as the physical and physicochemical properties of the synthesized powder, was examined. XRD results indicate that increasing the amount of fuel, particularly glycine, creates a stable environment for the crystallization of FeTiO3 nanoparticles. Moreover, enhancing the carbon content in precursor solutions with urea enhances reduction conditions and boosts the stability of FeTiO3 in the final product. The presence of carbon additives in glycine-fuel samples leads to unfavorable outcomes by increasing the levels of TiO2 and Fe3O4 undesirable phases. Incorporating additive carbon into the urea-synthesized precursor solution resulted in a particle size increase exceeding 50 nm and raised the combustion temperature by a minimum of 230 °C. Furthermore, the presence of 15 wt% additive carbon in the sample synthesized with glycine improved the specific surface area of particles from 2.44 m2/g to 18.41 m2/g. Obtained results have shown that achieving high crystallinity of FeTiO3 nanopowder is feasible through a one-step solution combustion synthesis process. This can be accomplished by carefully choosing the synthesis conditions, such as the type and quantity of fuel, along with the carbon additive.
{"title":"The effect of carbon addition on the synthesis process and the physical/electrocatalytic properties of FeTiO3 nanopowder produced by solution combustion synthesis method","authors":"Saman Soltani Alasvand, Sahar Mollazadeh Beidokhti, Jalil Vahdati Khaki, Erfan Hassanizadeh","doi":"10.1016/j.ceramint.2024.09.153","DOIUrl":"10.1016/j.ceramint.2024.09.153","url":null,"abstract":"<div><div>The FeTiO<sub>3</sub> nanopowder is a vital engineering material known for its exceptional performance in energy generation, storage, electrochemical sensors, and catalysis. However, synthesizing FeTiO<sub>3</sub> nanopowder with high crystallinity and phase purity typically requires specialized equipment and controlled heat treatment due to the instability of Fe<sup>2+</sup> ions. Using the one-step solution combustion synthesis (SCS) method, FeTiO<sub>3</sub> nanopowder withe high crystallinity were successfully produced utilizing basic equipment. Additionally, the influence of carbon additives on phase transitions, as well as the physical and physicochemical properties of the synthesized powder, was examined. XRD results indicate that increasing the amount of fuel, particularly glycine, creates a stable environment for the crystallization of FeTiO<sub>3</sub> nanoparticles. Moreover, enhancing the carbon content in precursor solutions with urea enhances reduction conditions and boosts the stability of FeTiO<sub>3</sub> in the final product. The presence of carbon additives in glycine-fuel samples leads to unfavorable outcomes by increasing the levels of TiO<sub>2</sub> and Fe<sub>3</sub>O<sub>4</sub> undesirable phases. Incorporating additive carbon into the urea-synthesized precursor solution resulted in a particle size increase exceeding 50 nm and raised the combustion temperature by a minimum of 230 °C. Furthermore, the presence of 15 wt% additive carbon in the sample synthesized with glycine improved the specific surface area of particles from 2.44 m<sup>2</sup>/g to 18.41 m<sup>2</sup>/g. Obtained results have shown that achieving high crystallinity of FeTiO<sub>3</sub> nanopowder is feasible through a one-step solution combustion synthesis process. This can be accomplished by carefully choosing the synthesis conditions, such as the type and quantity of fuel, along with the carbon additive.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 22","pages":"Pages 48041-48063"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.248
Jitai Han , Sida Tang , Jiahui Guan , Yuyi Mao , Kui Zhu , Yin Li , Peng Li
This study delves into the influence of TiN and NbC ceramic particles on the phase structure, grain organization, microhardness, and wear resistance of FeCoNiCrAl High-Entropy Alloy (HEA) composite coatings produced through laser cladding. The integration of ceramic particles induced a dual BCC solid-solution phase structure (B2+BCC), with the formation of a TiNb phase upon the melting and interaction of TiN and NbC in the melt pool. The ceramic particles significantly modified the grain structure of the HEA coatings, disrupting the Columnar-to-Equiaxed Transition (CET) and favoring the emergence of equiaxed grains. The TiN particles induced a substantial refinement of grain size, albeit unevenly, while NbC had a milder effect. The combined presence of TiN and NbC particles resulted in a more uniform grain refinement, enhancing the mechanical properties of the coatings. Notably, the (TiN + NbC)/HEAs composite coating demonstrated superior mechanical performance under the synergistic effect of both ceramic particles. The average microhardness value increased by 55.80 % compared to 17-4Ph stainless steel, and the wear rate was reduced by 88.38 %, with the wear mechanism primarily involving abrasive and oxidative wear.
{"title":"Microstructure and wear property of (TiN + NbC) double ceramic phase-reinforced in FeCrNiCoAl high-entropy alloy coating fabricated by laser cladding","authors":"Jitai Han , Sida Tang , Jiahui Guan , Yuyi Mao , Kui Zhu , Yin Li , Peng Li","doi":"10.1016/j.ceramint.2024.09.248","DOIUrl":"10.1016/j.ceramint.2024.09.248","url":null,"abstract":"<div><div>This study delves into the influence of TiN and NbC ceramic particles on the phase structure, grain organization, microhardness, and wear resistance of FeCoNiCrAl High-Entropy Alloy (HEA) composite coatings produced through laser cladding. The integration of ceramic particles induced a dual BCC solid-solution phase structure (B2+BCC), with the formation of a TiNb phase upon the melting and interaction of TiN and NbC in the melt pool. The ceramic particles significantly modified the grain structure of the HEA coatings, disrupting the Columnar-to-Equiaxed Transition (CET) and favoring the emergence of equiaxed grains. The TiN particles induced a substantial refinement of grain size, albeit unevenly, while NbC had a milder effect. The combined presence of TiN and NbC particles resulted in a more uniform grain refinement, enhancing the mechanical properties of the coatings. Notably, the (TiN + NbC)/HEAs composite coating demonstrated superior mechanical performance under the synergistic effect of both ceramic particles. The average microhardness value increased by 55.80 % compared to 17-4Ph stainless steel, and the wear rate was reduced by 88.38 %, with the wear mechanism primarily involving abrasive and oxidative wear.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49066-49084"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.249
Shimaa M. Ali , Basma Ashour , Mohamed G. Farahat , Rabab M. El-Sherif
Water pollution is a critical issue that affects both human health and the environment. Biomass-based LaFeO3 is prepared by the microwave-assisted method using rice straw as a cellulose source. Then LaFeO3/graphene oxide (GO) composite is prepared by ultrasonication to facilitate the perovskite-GO binding. Raman and FTIR spectra of the prepared composite identify the presence of the perovskite, biochar, cellulose and GO oxide phases and proves the surface functional groups interactions. Transmission electron microscope image shows that the GO sheets are homogeneous covered with the perovskite nanoparticles. The adsorption performance of the LaFeO3/GO composite for the removal of methylene blue (MB) and congo red (CR) dyes from aqueous solution is optimized. Adsorption follows pseudo 2nd order kinetic model and Freundlich isotherm, with maximum adsorption capacities of 319.5 and 416.7 mg/g for MB and CR, respectively. These values are higher than those reported for magnetic GO composites, indicating the excellent adsorption ability of the proposed perovskite/GO composite. A thermodynamic study shows that the adsorption of MB is exothermic, while it is endothermic for CR and combines physisorption and chemisorption characteristics for both dyes. The proposed adsorbent shows a good performance in the presence of NaCl interferent, with the possibility of regeneration and efficient successive reuse.
{"title":"Biomass-based perovskite/graphene oxide composite for the removal of organic pollutants from wastewater","authors":"Shimaa M. Ali , Basma Ashour , Mohamed G. Farahat , Rabab M. El-Sherif","doi":"10.1016/j.ceramint.2024.09.249","DOIUrl":"10.1016/j.ceramint.2024.09.249","url":null,"abstract":"<div><div>Water pollution is a critical issue that affects both human health and the environment. Biomass-based LaFeO<sub>3</sub> is prepared by the microwave-assisted method using rice straw as a cellulose source. Then LaFeO<sub>3</sub>/graphene oxide (GO) composite is prepared by ultrasonication to facilitate the perovskite-GO binding. Raman and FTIR spectra of the prepared composite identify the presence of the perovskite, biochar, cellulose and GO oxide phases and proves the surface functional groups interactions. Transmission electron microscope image shows that the GO sheets are homogeneous covered with the perovskite nanoparticles. The adsorption performance of the LaFeO<sub>3</sub>/GO composite for the removal of methylene blue (MB) and congo red (CR) dyes from aqueous solution is optimized. Adsorption follows pseudo 2nd order kinetic model and Freundlich isotherm, with maximum adsorption capacities of 319.5 and 416.7 mg/g for MB and CR, respectively. These values are higher than those reported for magnetic GO composites, indicating the excellent adsorption ability of the proposed perovskite/GO composite. A thermodynamic study shows that the adsorption of MB is exothermic, while it is endothermic for CR and combines physisorption and chemisorption characteristics for both dyes. The proposed adsorbent shows a good performance in the presence of NaCl interferent, with the possibility of regeneration and efficient successive reuse.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49085-49094"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.241
Jiawen Pan , Jiaqi Geng , Qunwei Guo , Lu Zou , Bo Chi , Jian Pu
Al2O3 with the desired electrical insulating properties and thermal shock resistivity has been extensively applied in the field of solid oxide fuel cells and oxygen sensors. However, degradation of the insulating Al2O3 layer is an intractable issue in practical applications. In this study, different point defect structures of Al2O3 were realized with the substitutional doping effect of ZrO2 and MgO. The MgO dopant provides positively charged oxygen vacancies, whereas the ZrO2 dopant tends to trigger negatively charged vacancy formation at Al3+ sites. The oxygen vacancy concentration of Al2O3 exhibits the following trend: MgO-doped Al2O3 > Al2O3 > ZrO2-doped Al2O3. Furthermore, the densification morphology, insulating properties, and oxygen vacancy migration of Al2O3 have been confirmed to be largely affected by the extrinsic factors. This study indicates that oxygen vacancy migration depends on the applied electric field at high temperatures. As the voltage and temperature increase, oxygen vacancy migration shows obvious electric-field-dependent characteristics, and its aggregation macroscopically shows hole defects. The defect position of Al2O3 is nonstoichiometric Al2O3-x with poor crystallinity. Therefore, it is believed that the oxygen vacancy migration triggered by the second phase directly determines the insulation performance and causes the degradation of Al2O3 materials.
{"title":"Insight into insulation degradation mechanism of Al2O3 involved with positive and negative defects","authors":"Jiawen Pan , Jiaqi Geng , Qunwei Guo , Lu Zou , Bo Chi , Jian Pu","doi":"10.1016/j.ceramint.2024.09.241","DOIUrl":"10.1016/j.ceramint.2024.09.241","url":null,"abstract":"<div><div>Al<sub>2</sub>O<sub>3</sub> with the desired electrical insulating properties and thermal shock resistivity has been extensively applied in the field of solid oxide fuel cells and oxygen sensors. However, degradation of the insulating Al<sub>2</sub>O<sub>3</sub> layer is an intractable issue in practical applications. In this study, different point defect structures of Al<sub>2</sub>O<sub>3</sub> were realized with the substitutional doping effect of ZrO<sub>2</sub> and MgO. The MgO dopant provides positively charged oxygen vacancies, whereas the ZrO<sub>2</sub> dopant tends to trigger negatively charged vacancy formation at Al<sup>3+</sup> sites. The oxygen vacancy concentration of Al<sub>2</sub>O<sub>3</sub> exhibits the following trend: MgO-doped Al<sub>2</sub>O<sub>3</sub> > Al<sub>2</sub>O<sub>3</sub> > ZrO<sub>2</sub>-doped Al<sub>2</sub>O<sub>3</sub>. Furthermore, the densification morphology, insulating properties, and oxygen vacancy migration of Al<sub>2</sub>O<sub>3</sub> have been confirmed to be largely affected by the extrinsic factors. This study indicates that oxygen vacancy migration depends on the applied electric field at high temperatures. As the voltage and temperature increase, oxygen vacancy migration shows obvious electric-field-dependent characteristics, and its aggregation macroscopically shows hole defects. The defect position of Al<sub>2</sub>O<sub>3</sub> is nonstoichiometric Al<sub>2</sub>O<sub>3-x</sub> with poor crystallinity. Therefore, it is believed that the oxygen vacancy migration triggered by the second phase directly determines the insulation performance and causes the degradation of Al<sub>2</sub>O<sub>3</sub> materials.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49003-49010"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.247
Guang-Xin Mao , Jia-Min Wu , Chong Tian , Chun-Lei Liu , Xin Lin , Fen Wang , Hai-Sheng Xu , Yu-Sheng Shi
Porous Si3N4 ceramics are widely applied in aerospace and mechanical fields owing to their excellent properties. Furthermore, vat photopolymerization (VPP) technology can fabricate Si3N4 components with complicated structures and high precision, but its layer-by-layer printing method leads to poor mechanical properties of ceramics. In this study, porous Si3N4 ceramics with a porosity of 28.41 % strengthened by directional β-Si3N4 were fabricated by combining VPP technology and seeding method. Rheological behavior and curing properties of the slurry were explored, and the influence of β-Si3N4 content on the mechanical properties of printed Si3N4 ceramics was investigated systematically. With the increase of β-Si3N4 content, the orientation degree of β-Si3N4 grains increased gradually, while fracture toughness and flexural strength of the ceramics exhibited a trend of increased first and then decreased and Vickers hardness gradually decreased. As β-Si3N4 content increased to 5 wt%, the fracture toughness and flexural strength of porous Si3N4 ceramics were improved from 4.23 MPa m1/2 and 214.7 MPa–5.65 MPa m1/2 and 272.0 MPa, respectively. Therefore, this work indicates that vat photopolymerization combined with seeding method is a promising approach for the fabrication of porous Si3N4 ceramics with high performance and complex structures.
{"title":"Improved mechanical properties of porous Si3N4 ceramics strengthened by β-Si3N4 seeds fabricated by vat photopolymerization","authors":"Guang-Xin Mao , Jia-Min Wu , Chong Tian , Chun-Lei Liu , Xin Lin , Fen Wang , Hai-Sheng Xu , Yu-Sheng Shi","doi":"10.1016/j.ceramint.2024.09.247","DOIUrl":"10.1016/j.ceramint.2024.09.247","url":null,"abstract":"<div><div>Porous Si<sub>3</sub>N<sub>4</sub> ceramics are widely applied in aerospace and mechanical fields owing to their excellent properties. Furthermore, vat photopolymerization (VPP) technology can fabricate Si<sub>3</sub>N<sub>4</sub> components with complicated structures and high precision, but its layer-by-layer printing method leads to poor mechanical properties of ceramics. In this study, porous Si<sub>3</sub>N<sub>4</sub> ceramics with a porosity of 28.41 % strengthened by directional β-Si<sub>3</sub>N<sub>4</sub> were fabricated by combining VPP technology and seeding method. Rheological behavior and curing properties of the slurry were explored, and the influence of β-Si<sub>3</sub>N<sub>4</sub> content on the mechanical properties of printed Si<sub>3</sub>N<sub>4</sub> ceramics was investigated systematically. With the increase of β-Si<sub>3</sub>N<sub>4</sub> content, the orientation degree of β-Si<sub>3</sub>N<sub>4</sub> grains increased gradually, while fracture toughness and flexural strength of the ceramics exhibited a trend of increased first and then decreased and Vickers hardness gradually decreased. As β-Si<sub>3</sub>N<sub>4</sub> content increased to 5 wt%, the fracture toughness and flexural strength of porous Si<sub>3</sub>N<sub>4</sub> ceramics were improved from 4.23 MPa m<sup>1/2</sup> and 214.7 MPa–5.65 MPa m<sup>1/2</sup> and 272.0 MPa, respectively. Therefore, this work indicates that vat photopolymerization combined with seeding method is a promising approach for the fabrication of porous Si<sub>3</sub>N<sub>4</sub> ceramics with high performance and complex structures.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49058-49065"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.246
Hongning Zhang, Tianni Lu, Qianxi Zhang, Zhenwei Huang, Na Li, Jinman Zhang, Chunzhong Liu
In this study, the thermal barrier material Yttria Stabilized Zirconia (YSZ) and the electromagnetic wave (EMW) absorbing agent samarium iron nitrogen (SmFeN) were used to prepare a YSZ/SmFeN/YSZ sandwich-structured composite. The YSZ/SmFeN interface was prepared perpendicular to the directions of EMWs. The EMW attenuation of the composites with different SmFeN contents and their mechanisms were studied using electromagnetic parameters, impedance matching, Cole–Cole circles, and minimum reflection loss (RLmin value). Dielectric loss was the dominant mechanism behind EMW attenuation for the composites. In addition, the dipole orientation of SmFeN and the presence of phase interface induced the dielectric loss. The mechanism of dipole orientation polarization was influenced by SmFeN content; the lesser the SmFeN content in the composite, the higher the ε (real part of dielectric coefficient). The frequency at which ε peaked shifted decreased with increasing SmFeN content. Higher dielectric losses were observed in the frequency band of 4.0–8.0 GHz. The EMW absorption rate showed that the optimum EMW absorption effect was achieved when the thickness ratio of YSZ:SmFeN:YSZ was 1:4:1 and the thickness is 3.325 mm. The corresponding RLmin was −35.3 dB and effective absorption bandwidth was 9.5 GHz (8.3–17.9 GHz).
{"title":"Effects of the SmFeN content on the electromagnetic wave absorbing properties of sandwich-structured YSZ/SmFeN/YSZ composites","authors":"Hongning Zhang, Tianni Lu, Qianxi Zhang, Zhenwei Huang, Na Li, Jinman Zhang, Chunzhong Liu","doi":"10.1016/j.ceramint.2024.09.246","DOIUrl":"10.1016/j.ceramint.2024.09.246","url":null,"abstract":"<div><div>In this study, the thermal barrier material Yttria Stabilized Zirconia (YSZ) and the electromagnetic wave (EMW) absorbing agent samarium iron nitrogen (SmFeN) were used to prepare a YSZ/SmFeN/YSZ sandwich-structured composite. The YSZ/SmFeN interface was prepared perpendicular to the directions of EMWs. The EMW attenuation of the composites with different SmFeN contents and their mechanisms were studied using electromagnetic parameters, impedance matching, Cole–Cole circles, and minimum reflection loss (<em>RL</em><sub><em>min</em></sub> value). Dielectric loss was the dominant mechanism behind EMW attenuation for the composites. In addition, the dipole orientation of SmFeN and the presence of phase interface induced the dielectric loss. The mechanism of dipole orientation polarization was influenced by SmFeN content; the lesser the SmFeN content in the composite, the higher the <em>ε</em> <span><math><mrow><mo>′</mo></mrow></math></span> (real part of dielectric coefficient). The frequency at which ε <span><math><mrow><mo>′</mo></mrow></math></span> peaked shifted decreased with increasing SmFeN content. Higher dielectric losses were observed in the frequency band of 4.0–8.0 GHz. The EMW absorption rate showed that the optimum EMW absorption effect was achieved when the thickness ratio of YSZ:SmFeN:YSZ was 1:4:1 and the thickness is 3.325 mm. The corresponding <em>RL</em><sub><em>min</em></sub> was −35.3 dB and effective absorption bandwidth was 9.5 GHz (8.3–17.9 GHz).</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49051-49057"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.252
R. Gago , S. Prucnal , J. Azpeitia , I. Jiménez , L. Álvarez-Fraga
We report the impact of flash-lamp-annealing (FLA) on the structural evolution of amorphous titania (TiO2) films produced by DC reactive magnetron sputtering. TiO2 films were grown at room-temperature at different oxygen partial pressure (PO2) and subsequently annealed as a function of the FLA energy density. X-ray diffraction confirms that FLA induces phase formation from the initial amorphous state with a general transition from anatase to rutile by increasing the FLA energy density (temperature). Interestingly, the transformation onset of anatase to rutile is achieved at lower energy densities for higher PO2. On the contrary, films with a highly resilient anatase phase can be produced at relatively low PO2. A detailed analysis of the pristine amorphous structure carried out by X-ray absorption near-edge structure indicates the role of oxygen sites in the observed phase transformation. In particular, oxygen vacancies seem to stabilize the anatase phase at high temperatures. The results show the relevance of subtle changes in the initial amorphous structure for phase selectivity in TiO2 films upon FLA.
{"title":"Phase selectivity upon flash-lamp annealing of sputter deposited amorphous titanium oxide films","authors":"R. Gago , S. Prucnal , J. Azpeitia , I. Jiménez , L. Álvarez-Fraga","doi":"10.1016/j.ceramint.2024.09.252","DOIUrl":"10.1016/j.ceramint.2024.09.252","url":null,"abstract":"<div><div>We report the impact of flash-lamp-annealing (FLA) on the structural evolution of amorphous titania (TiO<sub>2</sub>) films produced by DC reactive magnetron sputtering. TiO<sub>2</sub> films were grown at room-temperature at different oxygen partial pressure (<em>P</em><sub><em>O2</em></sub>) and subsequently annealed as a function of the FLA energy density. X-ray diffraction confirms that FLA induces phase formation from the initial amorphous state with a general transition from anatase to rutile by increasing the FLA energy density (temperature). Interestingly, the transformation onset of anatase to rutile is achieved at lower energy densities for higher <em>P</em><sub><em>O2</em></sub>. On the contrary, films with a highly resilient anatase phase can be produced at relatively low <em>P</em><sub><em>O2</em></sub>. A detailed analysis of the pristine amorphous structure carried out by X-ray absorption near-edge structure indicates the role of oxygen sites in the observed phase transformation. In particular, oxygen vacancies seem to stabilize the anatase phase at high temperatures. The results show the relevance of subtle changes in the initial amorphous structure for phase selectivity in TiO<sub>2</sub> films upon FLA.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 49112-49118"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.ceramint.2024.09.239
Zhuan Zhao , Muhammad Amin Padhiar , Shaolin Zhang , Teng Ma , Noor Zamin Khan , Yongqiang Ji , Zubair Maroof , Shusheng Pan
Perovskite nanocrystals (NCs) are emerging as a next generation display technology. In this regard, exploring the structural and optical stability when subjected to radiation is crucial for expanding their application in aerospace and radiation detection technologies. In this study, we investigated the effects of gamma radiation on CsPbBr3 heterojunction thin films through a comprehensive analysis of their structural and optical characteristics. The thin films of CsPbBr3 were subjected to varying doses of gamma radiation, ranging from 100 krad to 1 Mrad, followed by thorough examination using X-ray diffraction (XRD) and optical spectroscopy techniques. Our findings unveil significant changes in the crystal structure of CsPbBr3 thin films when exposed to gamma radiation, including shifts in diffraction peak positions from cubic to monoclinic phases, broadening of peaks, and variations in peak intensities due to induced surface defects. The optical properties, such electroluminescence (EL) and photoluminescence (PL) intensity slightly drops at the moderate irradiation dose of 300 krad, while at an irradiation dose of 1 Mrad deteriorated severely. Notably, 300 krad is equivalent to the radiation dose accumulated by satellites in low-Earth orbit over 10 years. The findings in this work suggest the fabricated CsPbBr3 thin film has the potential to be used in space applications.
{"title":"Gamma radiation-induced changes in the structural and optical properties of CsPbBr3 thin films for space applications","authors":"Zhuan Zhao , Muhammad Amin Padhiar , Shaolin Zhang , Teng Ma , Noor Zamin Khan , Yongqiang Ji , Zubair Maroof , Shusheng Pan","doi":"10.1016/j.ceramint.2024.09.239","DOIUrl":"10.1016/j.ceramint.2024.09.239","url":null,"abstract":"<div><div>Perovskite nanocrystals (NCs) are emerging as a next generation display technology. In this regard, exploring the structural and optical stability when subjected to radiation is crucial for expanding their application in aerospace and radiation detection technologies. In this study, we investigated the effects of gamma radiation on CsPbBr<sub>3</sub> heterojunction thin films through a comprehensive analysis of their structural and optical characteristics. The thin films of CsPbBr<sub>3</sub> were subjected to varying doses of gamma radiation, ranging from 100 krad to 1 Mrad, followed by thorough examination using X-ray diffraction (XRD) and optical spectroscopy techniques. Our findings unveil significant changes in the crystal structure of CsPbBr<sub>3</sub> thin films when exposed to gamma radiation, including shifts in diffraction peak positions from cubic to monoclinic phases, broadening of peaks, and variations in peak intensities due to induced surface defects. The optical properties, such electroluminescence (EL) and photoluminescence (PL) intensity slightly drops at the moderate irradiation dose of 300 krad, while at an irradiation dose of 1 Mrad deteriorated severely. Notably, 300 krad is equivalent to the radiation dose accumulated by satellites in low-Earth orbit over 10 years. The findings in this work suggest the fabricated CsPbBr<sub>3</sub> thin film has the potential to be used in space applications.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"50 23","pages":"Pages 48995-49002"},"PeriodicalIF":5.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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