Pub Date : 2025-02-10DOI: 10.1016/j.jeurceramsoc.2025.117275
R.T. Bhatt , J. Lang , S. Mital
Creep and cyclic fatigue durability of 3D woven SiC-fiber-reinforced SiC-matrix composites with a hybrid SiC matrix and three types of SiC fibers was investigated from 1300 to 1482 °C in air at stresses up to 150 MPa. The fiber types investigated were Sylramic™-iBN, super Sylramic™-iBN, and Hi-Nicalon™-S SiC fibers, and the hybrid SiC matrix was fabricated from a combination of chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis. Results indicate that accumulated strain during creep and cyclic fatigue at low stresses is predominantly controlled by the CVI SiC matrix, but durability of the composites is influenced by the SiC fiber types as well as the CVI SiC matrix. Composites containing super Sylramic™-iBN SiC fibers showed better durability compared to the composites containing the other two types of fiber. Potential applications and challenges of using this composite for highly loaded turbine components are discussed.
{"title":"Fiber effects on creep and cyclic durability of 3D woven SiC/SiC composites with a hybrid SiC matrix","authors":"R.T. Bhatt , J. Lang , S. Mital","doi":"10.1016/j.jeurceramsoc.2025.117275","DOIUrl":"10.1016/j.jeurceramsoc.2025.117275","url":null,"abstract":"<div><div>Creep and cyclic fatigue durability of 3D woven SiC-fiber-reinforced SiC-matrix composites with a hybrid SiC matrix and three types of SiC fibers was investigated from 1300 to 1482 °C in air at stresses up to 150 MPa. The fiber types investigated were Sylramic™-iBN, super Sylramic™-iBN, and Hi-Nicalon™-S SiC fibers, and the hybrid SiC matrix was fabricated from a combination of chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis. Results indicate that accumulated strain during creep and cyclic fatigue at low stresses is predominantly controlled by the CVI SiC matrix, but durability of the composites is influenced by the SiC fiber types as well as the CVI SiC matrix. Composites containing super Sylramic™-iBN SiC fibers showed better durability compared to the composites containing the other two types of fiber. Potential applications and challenges of using this composite for highly loaded turbine components are discussed.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117275"},"PeriodicalIF":5.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395734","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 : 2025-02-09DOI: 10.1016/j.jeurceramsoc.2025.117271
Getaw Abebe Tina, Rajeev Ranjan
We investigate the influence of oxygen deficient modifier BaAlO2.5 (BAO) on the structure, dielectric, and piezoelectric properties of the morphotropic phase boundary (MPB) composition Na1/2Bi1/2TiO3-6.5BaTiO3 (NBT-6.5BT) of the lead-free NBT-BT piezoceramic solid solution. We found that merely 1 mol percent of BAO increases the weak signal longitudinal piezoelectric coefficient (d33) from 164 pC/N to 205 pC/N. This is accompanied by a remarkable increase in the depolarization temperature (Td) from 85 °C to 160 °C respectively. We discuss the mechanism underlying the simultaneous increase in the d33 and Td in this system.
{"title":"Simultaneous enhancement of d33 and depolarization temperature of the morphotropic phase boundary composition of the Pb-free piezoceramic Na1/2Bi1/2TiO3–BaTiO3","authors":"Getaw Abebe Tina, Rajeev Ranjan","doi":"10.1016/j.jeurceramsoc.2025.117271","DOIUrl":"10.1016/j.jeurceramsoc.2025.117271","url":null,"abstract":"<div><div>We investigate the influence of oxygen deficient modifier BaAlO<sub>2.5</sub> (BAO) on the structure, dielectric, and piezoelectric properties of the morphotropic phase boundary (MPB) composition Na<sub>1/2</sub>Bi<sub>1/2</sub>TiO<sub>3</sub>-6.5BaTiO<sub>3</sub> (NBT-6.5BT) of the lead-free NBT-BT piezoceramic solid solution. We found that merely 1 mol percent of BAO increases the weak signal longitudinal piezoelectric coefficient (<em>d</em><sub>33</sub>) from 164 pC/N to 205 pC/N. This is accompanied by a remarkable increase in the depolarization temperature (T<sub>d</sub>) from 85 °C to 160 °C respectively. We discuss the mechanism underlying the simultaneous increase in the <em>d</em><sub>33</sub> and T<sub>d</sub> in this system.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117271"},"PeriodicalIF":5.8,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387740","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 : 2025-02-07DOI: 10.1016/j.jeurceramsoc.2025.117270
Hyun-Hee Choi , Bong-Gu Kim , Min-Gyu Kim , Ha-Eun Seo , Shiori Sakuraki , Sea-Hoon Lee , Yeon-Gil Jung , SeungCheol Yang
Heat treatment is essential for developing high-strength ceramics; however, maintaining dimensional stability post-treatment is challenging due to shrinkage and warpage. In this study, we synthesized sol-gel-derived cycloaliphatic epoxide oligosiloxane resins and applied them to ceramic bodies to enhance their shrinkage resistance. The optimal resin composition and synthetic conditions were determined by analyzing the bonding structures and thermal properties. The resin was blended with ceramic powders and heat-treated to assess its effects on fracture strength, thermal expansion, and dimensional stability. The hybrid binder with both organic and inorganic components significantly improved the mechanical properties and thermal stability of ceramics. Incorporating mixed particle sizes into the ceramic powder increased packing density, leading to a higher residual solid content after pyrolysis and reduced shrinkage during sintering. Even at temperatures above 1300 °C, minimal shrinkage was observed, making this approach promising for the production of high-performance ceramic parts for aerospace, automotive, and electronics applications.
{"title":"Epoxide-oligosiloxane hybrid resin for enhanced ceramic shrinkage resistance","authors":"Hyun-Hee Choi , Bong-Gu Kim , Min-Gyu Kim , Ha-Eun Seo , Shiori Sakuraki , Sea-Hoon Lee , Yeon-Gil Jung , SeungCheol Yang","doi":"10.1016/j.jeurceramsoc.2025.117270","DOIUrl":"10.1016/j.jeurceramsoc.2025.117270","url":null,"abstract":"<div><div>Heat treatment is essential for developing high-strength ceramics; however, maintaining dimensional stability post-treatment is challenging due to shrinkage and warpage. In this study, we synthesized sol-gel-derived cycloaliphatic epoxide oligosiloxane resins and applied them to ceramic bodies to enhance their shrinkage resistance. The optimal resin composition and synthetic conditions were determined by analyzing the bonding structures and thermal properties. The resin was blended with ceramic powders and heat-treated to assess its effects on fracture strength, thermal expansion, and dimensional stability. The hybrid binder with both organic and inorganic components significantly improved the mechanical properties and thermal stability of ceramics. Incorporating mixed particle sizes into the ceramic powder increased packing density, leading to a higher residual solid content after pyrolysis and reduced shrinkage during sintering. Even at temperatures above 1300 °C, minimal shrinkage was observed, making this approach promising for the production of high-performance ceramic parts for aerospace, automotive, and electronics applications.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 8","pages":"Article 117270"},"PeriodicalIF":5.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403460","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 : 2025-02-07DOI: 10.1016/j.jeurceramsoc.2025.117269
Sebin Park , Sooyeon Joo , Jong Seob Song , Jung-Hye Eom , Han Nam Cheong , Dang-Hyok Yoon
In this study aims, four key questions regarding the joining of silicon carbide (SiC) via Si–C reaction bonding are explored. These questions address the optimal filler composition for minimizing free Si, the effect of surface roughness on the joint strength, the ideal filler thickness for achieving the maximum joint strength, and the typical defects observed at the joint. To investigate these aspects, SiC was joined using a SiC/C filler tape with varying thicknesses of 10–100 μm, followed by molten Si infiltration at 1500℃ for 1 h under vacuum. Additionally, the surface roughness of the SiC base was adjusted to four levels to evaluate its effect on the joint strength, and common defects were identified. The results indicate that a finely polished SiC base joined with SiC/C = 70/30 wt% tape of ≤ 50 μm thickness achieved a high joint strength of ≥ 250 MPa.
{"title":"Optimizing Si–C reaction bonding for SiC joining: Effects of filler composition, thickness, and surface roughness on joint strength","authors":"Sebin Park , Sooyeon Joo , Jong Seob Song , Jung-Hye Eom , Han Nam Cheong , Dang-Hyok Yoon","doi":"10.1016/j.jeurceramsoc.2025.117269","DOIUrl":"10.1016/j.jeurceramsoc.2025.117269","url":null,"abstract":"<div><div>In this study aims, four key questions regarding the joining of silicon carbide (SiC) via Si–C reaction bonding are explored. These questions address the optimal filler composition for minimizing free Si, the effect of surface roughness on the joint strength, the ideal filler thickness for achieving the maximum joint strength, and the typical defects observed at the joint. To investigate these aspects, SiC was joined using a SiC/C filler tape with varying thicknesses of 10–100 μm, followed by molten Si infiltration at 1500℃ for 1 h under vacuum. Additionally, the surface roughness of the SiC base was adjusted to four levels to evaluate its effect on the joint strength, and common defects were identified. The results indicate that a finely polished SiC base joined with SiC/C = 70/30 wt% tape of ≤ 50 μm thickness achieved a high joint strength of ≥ 250 MPa.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117269"},"PeriodicalIF":5.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350857","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 : 2025-02-05DOI: 10.1016/j.jeurceramsoc.2025.117264
Caiyan Liu , Yunpeng Zhang , Dazhao Cheng , Liyang Shao , Changqing Teng , Lu Wu , Jing Zhang
This study investigates the formation of radially aligned columnar grains surrounding central voids in porous uranium dioxide (UO2) fuel rods, utilizing a multiphase field model to analyze the impact of pore migration. The results indicate that the transformation from equiaxed grains to columnar structures is driven by the directional migration of pores towards the fuel center, influenced by high temperatures and steep temperature gradients. Increased temperature gradients, porosity, and pore density enhance the columnar morphological features of the grains. As pores migrate, they attach to grain boundaries, facilitating the movement of circumferential grain boundaries while pinning radial ones. This interaction promotes directional grain coarsening towards the fuel center, ultimately resulting in distinct columnar grains. This research provides valuable insights into the complex interactions between pore dynamics and grain boundary behavior, elucidating the microstructural evolution of UO2 under operational conditions.
{"title":"Phase field simulation of columnar grain formation induced by pore migration in UO2","authors":"Caiyan Liu , Yunpeng Zhang , Dazhao Cheng , Liyang Shao , Changqing Teng , Lu Wu , Jing Zhang","doi":"10.1016/j.jeurceramsoc.2025.117264","DOIUrl":"10.1016/j.jeurceramsoc.2025.117264","url":null,"abstract":"<div><div>This study investigates the formation of radially aligned columnar grains surrounding central voids in porous uranium dioxide (UO<sub>2</sub>) fuel rods, utilizing a multiphase field model to analyze the impact of pore migration. The results indicate that the transformation from equiaxed grains to columnar structures is driven by the directional migration of pores towards the fuel center, influenced by high temperatures and steep temperature gradients. Increased temperature gradients, porosity, and pore density enhance the columnar morphological features of the grains. As pores migrate, they attach to grain boundaries, facilitating the movement of circumferential grain boundaries while pinning radial ones. This interaction promotes directional grain coarsening towards the fuel center, ultimately resulting in distinct columnar grains. This research provides valuable insights into the complex interactions between pore dynamics and grain boundary behavior, elucidating the microstructural evolution of UO<sub>2</sub> under operational conditions.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117264"},"PeriodicalIF":5.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377012","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 : 2025-02-05DOI: 10.1016/j.jeurceramsoc.2025.117263
Satyanarayana Sabat, Soumavo Sikder, Shantanu K. Behera, Arindam Paul
We investigated the influence of various pore architectures namely lamellar, dendritic and isotropic on uniaxial compressive response of freeze-cast porous alumina (platelets) scaffolds at quasistatic strain rate (10−4 s−1). The compressive response of the highly porous (>85 %) scaffolds exhibited cellular-like, damageable failure behaviour independent of pore structure. We suggest that high pore content (vis-à-vis less solid walls fraction) restricts the propagation of long, macroscopic cracks by crack-crack interaction along the lamella walls. This results in multiple fragments of the lamella walls by gradual crushing, a fundamental characteristic of cellular-like failure behaviour. Comparison of our experimental results with honeycomb out-of-plane deformation model derived by Gibson-Ashby further revealed that buckling induced elastic instability of the lamella walls is the strength (compressive) limiting mechanism. Microscopic observation showed extensive local damage of lamella walls (while the overall scaffolds remain intact at macroscopic level), which further confirms localized elastic instability (buckling) within lamella walls.
{"title":"Effect of pore architecture on quasistatic compressive deformation of freeze-cast porous alumina scaffolds","authors":"Satyanarayana Sabat, Soumavo Sikder, Shantanu K. Behera, Arindam Paul","doi":"10.1016/j.jeurceramsoc.2025.117263","DOIUrl":"10.1016/j.jeurceramsoc.2025.117263","url":null,"abstract":"<div><div>We investigated the influence of various pore architectures namely lamellar, dendritic and isotropic on uniaxial compressive response of freeze-cast porous alumina (platelets) scaffolds at quasistatic strain rate (10<sup>−4</sup> s<sup>−1</sup>). The compressive response of the highly porous (>85 %) scaffolds exhibited cellular-like, damageable failure behaviour independent of pore structure. We suggest that high pore content (vis-à-vis less solid walls fraction) restricts the propagation of long, macroscopic cracks by crack-crack interaction along the lamella walls. This results in multiple fragments of the lamella walls by gradual crushing, a fundamental characteristic of cellular-like failure behaviour. Comparison of our experimental results with honeycomb out-of-plane deformation model derived by Gibson-Ashby further revealed that buckling induced elastic instability of the lamella walls is the strength (compressive) limiting mechanism. Microscopic observation showed extensive local damage of lamella walls (while the overall scaffolds remain intact at macroscopic level), which further confirms localized elastic instability (buckling) within lamella walls.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117263"},"PeriodicalIF":5.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350856","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 : 2025-02-04DOI: 10.1016/j.jeurceramsoc.2025.117261
Annamária Naughton-Duszová , Dávid Medveď , Monika Hrubovčáková , Ondrej Petruš , Marek Vojtko , Peter Švec , Ľubomír Medvecký , Pavol Hvizdoš , Ján Dusza
Nanohardness of grains and grain boundaries in reactive spark plasma sintered dual-phase (Ti0.82Zr0.04Nb0.08Hf0.03Ta0.03)B2 + (Ti0.49Zr0.12Nb0.13Hf0.11Ta0.15)C high-entropy composite was investigated. The composite with a high relative density of 99.8 %, consists predominantly of carbide (∼56.4 vol%) and boride (∼39.7 vol%) phases with average grain sizes of 2.2 μm and 3.4 μm of the carbide and boride phases, respectively. Most grain/phase boundaries show a continuous sharp ∼ 1.5 nm wide segregation of Fe, Co, and Ni impurities. Nanohardness was measured by nanoindentation on polished/non-deformed and worn/deformed surfaces. At non-deformed surface, the average hardness/Young’s modulus of boride and carbide grains are 41.3 ± 2.9 GPa/596 ± 25 GPa and 38.3 ± 2.3 GPa/553 ± 24 GPa, respectively. At the vicinity of grain boundaries, the hardness/Young modulus is 37.3 ± 2.5 GPa/600 ± 32 GPa. At deformed surfaces, the average hardness of boride grains is higher and the average hardness of carbide grains is slightly higher compared to the values at non-deformed surfaces, with values of 42.4 ± 3.9 GPa, and 38.4 ± 2.4 GPa, respectively.
{"title":"Nanohardness of grains and grain boundaries in reactive sintered (Ti-Zr-Nb-Hf-Ta)B2 + (Ti-Zr-Nb-Hf-Ta)C composite","authors":"Annamária Naughton-Duszová , Dávid Medveď , Monika Hrubovčáková , Ondrej Petruš , Marek Vojtko , Peter Švec , Ľubomír Medvecký , Pavol Hvizdoš , Ján Dusza","doi":"10.1016/j.jeurceramsoc.2025.117261","DOIUrl":"10.1016/j.jeurceramsoc.2025.117261","url":null,"abstract":"<div><div>Nanohardness of grains and grain boundaries in reactive spark plasma sintered dual-phase (Ti<sub>0.82</sub>Zr<sub>0.04</sub>Nb<sub>0.08</sub>Hf<sub>0.03</sub>Ta<sub>0.03</sub>)B<sub>2</sub> + (Ti<sub>0.49</sub>Zr<sub>0.12</sub>Nb<sub>0.13</sub>Hf<sub>0.11</sub>Ta<sub>0.15</sub>)C high-entropy composite was investigated. The composite with a high relative density of 99.8 %, consists predominantly of carbide (∼56.4 vol%) and boride (∼39.7 vol%) phases with average grain sizes of 2.2 μm and 3.4 μm of the carbide and boride phases, respectively. Most grain/phase boundaries show a continuous sharp ∼ 1.5 nm wide segregation of Fe, Co, and Ni impurities. Nanohardness was measured by nanoindentation on polished/non-deformed and worn/deformed surfaces. At non-deformed surface, the average hardness/Young’s modulus of boride and carbide grains are 41.3 ± 2.9 GPa/596 ± 25 GPa and 38.3 ± 2.3 GPa/553 ± 24 GPa, respectively. At the vicinity of grain boundaries, the hardness/Young modulus is 37.3 ± 2.5 GPa/600 ± 32 GPa. At deformed surfaces, the average hardness of boride grains is higher and the average hardness of carbide grains is slightly higher compared to the values at non-deformed surfaces, with values of 42.4 ± 3.9 GPa, and 38.4 ± 2.4 GPa, respectively.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117261"},"PeriodicalIF":5.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395735","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 : 2025-02-04DOI: 10.1016/j.jeurceramsoc.2025.117259
Justyna Ignaczak , Maciej Bik , Jan Jamroz , Karolina Górnicka , Agnieszka Drewniak , Jakub Karczewski , Piotr Jasiński , Sebastian Molin
The current coating materials for steel interconnects in SOCs (Solid Oxide Cells) typically rely on critical raw materials, specifically Co oxide spinels. A new approach is using copper-based spinel coatings, which are promising concerning price, conductivity, and sustainability. This investigation is dedicated to an evaluation of a commercially available powder provided by the Kceracell company with stoichiometric Mn1.9CuFe0.1O4 as a protective material on the interconnects. The material was electrophoretically deposited onto a ferritic stainless-steel support and subsequently assessed. Prior to deposition, the powders underwent crystallographic phase analysis at high temperatures and electrical conductivity. The coated steel samples were oxidized in an air atmosphere at 750 °C for 5000 hours. The structure of the coating / steel system was evaluated before and after high temperature exposition by means of SEM-EDX, Raman spectroscopy, X-ray diffraction. The electrical properties of the steel-coating system were assessed through Area Specific Resistance measurements. The results indicate that the evaluated coatings react with Cr from the substrate during long-term oxidation and create a (Mn,Cu,Fe,Cr)3O4 spinel reaction layer, thus the whole system exhibits satisfactory resistance.
{"title":"Development and evaluation of interconnect protective coatings based on commercial Mn1.9CuFe0.1O4 spinel powder","authors":"Justyna Ignaczak , Maciej Bik , Jan Jamroz , Karolina Górnicka , Agnieszka Drewniak , Jakub Karczewski , Piotr Jasiński , Sebastian Molin","doi":"10.1016/j.jeurceramsoc.2025.117259","DOIUrl":"10.1016/j.jeurceramsoc.2025.117259","url":null,"abstract":"<div><div>The current coating materials for steel interconnects in SOCs (Solid Oxide Cells) typically rely on critical raw materials, specifically Co oxide spinels. A new approach is using copper-based spinel coatings, which are promising concerning price, conductivity, and sustainability. This investigation is dedicated to an evaluation of a commercially available powder provided by the Kceracell company with stoichiometric Mn<sub>1.9</sub>CuFe<sub>0.1</sub>O<sub>4</sub> as a protective material on the interconnects. The material was electrophoretically deposited onto a ferritic stainless-steel support and subsequently assessed. Prior to deposition, the powders underwent crystallographic phase analysis at high temperatures and electrical conductivity. The coated steel samples were oxidized in an air atmosphere at 750 °C for 5000 hours. The structure of the coating / steel system was evaluated before and after high temperature exposition by means of SEM-EDX, Raman spectroscopy, X-ray diffraction. The electrical properties of the steel-coating system were assessed through Area Specific Resistance measurements. The results indicate that the evaluated coatings react with Cr from the substrate during long-term oxidation and create a (Mn,Cu,Fe,Cr)<sub>3</sub>O<sub>4</sub> spinel reaction layer, thus the whole system exhibits satisfactory resistance.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117259"},"PeriodicalIF":5.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350858","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}
Yttria-doped zirconia has been shown to undergo nitridation in air by flash sintering using direct current (DC) electric fields, resulting in the formation of zirconium oxynitride, Zr(N,O). This study performed the microstructure analysis primarily using scanning transmission electron microscopy for 8 mol%Y2O3-ZrO2 (8YSZ) nitrided by isothermal flash sintering protocol under DC electric fields in air. The findings confirmed the existence of a threshold current density for Zr(N,O) formation. The nitrided 8YSZ grains comprised crystal-oriented Zr(N,O) fine ellipsoid-shaped grains with 10 – 20 nm in size. The formation of this structure is attributed to the nucleation manner of the Zr(N,O) grains to align their {001} planes to those of the original 8YSZ grains. The transformation of 8YSZ into Zr(N,O) during nitridation could be considered to precede by a replacement of their anions from oxygen to nitrogen while maintaining the cation framework of the respective crystal structures, as predicted by Bechteler et al.
{"title":"Microstructure analysis for zirconium oxynitrides formed in 8 mol% yttria-doped zirconia by a flash event under a direct current electric field in an ambient atmosphere","authors":"Shunichi Sakamoto , Ayu Kodaira , Tomoharu Tokunaga , Nobuhiro Morisaki , Kiyoshi Kobayashi , Takahisa Yamamoto","doi":"10.1016/j.jeurceramsoc.2025.117265","DOIUrl":"10.1016/j.jeurceramsoc.2025.117265","url":null,"abstract":"<div><div>Yttria-doped zirconia has been shown to undergo nitridation in air by flash sintering using direct current (DC) electric fields, resulting in the formation of zirconium oxynitride, Zr(N,O). This study performed the microstructure analysis primarily using scanning transmission electron microscopy for 8 mol%Y<sub>2</sub>O<sub>3</sub>-ZrO<sub>2</sub> (8YSZ) nitrided by isothermal flash sintering protocol under DC electric fields in air. The findings confirmed the existence of a threshold current density for Zr(N,O) formation. The nitrided 8YSZ grains comprised crystal-oriented Zr(N,O) fine ellipsoid-shaped grains with 10 – 20 nm in size. The formation of this structure is attributed to the nucleation manner of the Zr(N,O) grains to align their {001} planes to those of the original 8YSZ grains. The transformation of 8YSZ into Zr(N,O) during nitridation could be considered to precede by a replacement of their anions from oxygen to nitrogen while maintaining the cation framework of the respective crystal structures, as predicted by Bechteler et al.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117265"},"PeriodicalIF":5.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143332456","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 : 2025-02-04DOI: 10.1016/j.jeurceramsoc.2025.117260
Joseph Alemzadeh , Rut Benavente , Amparo Borrell , Carlos Gutiérrez-González , Marta Suárez , Luis A. Diaz , Miguel A. Montes-Morán , Clara Blanco , Sam L. Evans , Victoria G. Rocha
Balancing the mechanical and functional properties of graphene-reinforced ceramics can be a challenge because agglomeration of the reinforcement must be avoided to minimise microstructural defects and it is difficult to organise the constituents into meaningful structures. The water-based processing strategy that is demonstrated here illustrates the potential to fabricate layered alumina composites using a combination of freeze-casting, vacuum infiltration, and spark plasma sintering. Layers of alumina between 0.5 and 7 μm thick and consist of an average grain size of 0.7 ± 0.4 μm were separated by highly-oriented reduced graphene oxide. Mechanical and functional properties were investigated alongside a monolithic counterpart sintered at 1300 °C. The flexural strength and fracture toughness increased from 262 to 314 MPa and 3.5–5.4 MPa m1/2 respectively, whilst electrical conductivity rose by nine orders of magnitude to 10−1 S cm−1.
{"title":"Novel water-based processing of graphene oxide and sub-micrometric alumina towards tougher and electrically-conductive structural ceramics","authors":"Joseph Alemzadeh , Rut Benavente , Amparo Borrell , Carlos Gutiérrez-González , Marta Suárez , Luis A. Diaz , Miguel A. Montes-Morán , Clara Blanco , Sam L. Evans , Victoria G. Rocha","doi":"10.1016/j.jeurceramsoc.2025.117260","DOIUrl":"10.1016/j.jeurceramsoc.2025.117260","url":null,"abstract":"<div><div>Balancing the mechanical and functional properties of graphene-reinforced ceramics can be a challenge because agglomeration of the reinforcement must be avoided to minimise microstructural defects and it is difficult to organise the constituents into meaningful structures. The water-based processing strategy that is demonstrated here illustrates the potential to fabricate layered alumina composites using a combination of freeze-casting, vacuum infiltration, and spark plasma sintering. Layers of alumina between 0.5 and 7 μm thick and consist of an average grain size of 0.7 ± 0.4 μm were separated by highly-oriented reduced graphene oxide. Mechanical and functional properties were investigated alongside a monolithic counterpart sintered at 1300 °C. The flexural strength and fracture toughness increased from 262 to 314 MPa and 3.5–5.4 MPa m<sup>1/2</sup> respectively, whilst electrical conductivity rose by nine orders of magnitude to 10<sup>−1</sup> S cm<sup>−1</sup>.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117260"},"PeriodicalIF":5.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378995","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}
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