Pub Date : 2025-02-03DOI: 10.1016/j.jeurceramsoc.2025.117250
Yue Zhou , Xiaoqing He , William G. Fahrenholtz , Gregory E. Hilmas , Scott J. McCormack
Zirconium diboride (ZrB2) ceramics with carbon additions ranging from 0 to 1.5 wt% were densified by hot-pressing. Commercial ZrB2 powder was the starting powder and phenolic resin was used as the carbon source. Without carbon addition, ZrB2 can be fully densified at 2150℃ under 32 MPa resulting in an average grain size of 27.2 µm. With carbon additions to the ZrB2, the relative density remained near 100 %, but the grain size decreased as carbon content increased. In addition to ZrB2, small amounts of secondary phases (graphite, B4C, and BN) were detected in the hot-pressed ceramics along grain boundaries. Thermal diffusivity, specific heat capacity, and thermal conductivity of ZrB2 were measured as a function of carbon additions. The composition with 0.75 wt% of carbon exhibited the best combination of high relative density, small grain size, and high thermal diffusivity.
{"title":"Densification of zirconium diboride with varying carbon additions","authors":"Yue Zhou , Xiaoqing He , William G. Fahrenholtz , Gregory E. Hilmas , Scott J. McCormack","doi":"10.1016/j.jeurceramsoc.2025.117250","DOIUrl":"10.1016/j.jeurceramsoc.2025.117250","url":null,"abstract":"<div><div>Zirconium diboride (ZrB<sub>2</sub>) ceramics with carbon additions ranging from 0 to 1.5 wt% were densified by hot-pressing. Commercial ZrB<sub>2</sub> powder was the starting powder and phenolic resin was used as the carbon source. Without carbon addition, ZrB<sub>2</sub> can be fully densified at 2150℃ under 32 MPa resulting in an average grain size of 27.2 µm. With carbon additions to the ZrB<sub>2</sub>, the relative density remained near 100 %, but the grain size decreased as carbon content increased. In addition to ZrB<sub>2</sub>, small amounts of secondary phases (graphite, B<sub>4</sub>C, and BN) were detected in the hot-pressed ceramics along grain boundaries. Thermal diffusivity, specific heat capacity, and thermal conductivity of ZrB<sub>2</sub> were measured as a function of carbon additions. The composition with 0.75 wt% of carbon exhibited the best combination of high relative density, small grain size, and high thermal diffusivity.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117250"},"PeriodicalIF":5.8,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378996","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 : 2025-02-02DOI: 10.1016/j.jeurceramsoc.2025.117252
Andrés Mormeneo-Segarra , Thomas Hérisson de Beauvoir , Sergio Ferrer-Nicomedes , Nuria Vicente-Agut , Claude Estournès , Antonio Barba-Juan
The Cold Sintering Process has been used to sinter Li1.3Al0.3Ti1.7(PO4)3 powder (LATP) initially mixed with 15 wt% of a solution of acetic acid 3 m as Transient Liquid Phase (TLP). The effect of variables such as green density, heating rate, sintering temperature, dwell time and the operating pressure on the densification of LATP via CSP has been thoroughly analysed. The operating pressure shows no effect on the green density above 450 MPa. The heating rates, thus the heating time, do not modify the densification behavior of LATP Solid-State Electrolytes (SSEs) but a decomposition reaction takes place at temperatures above 180 ºC. This reaction depends on the TLP amount still present in the pores, and at higher pressures (P > 450 MPa) this decomposition effect on densification is reduced as the pore volume becomes smaller. For the first time in the CSP, a linear dependence of relative density on temperature is demonstrated.
{"title":"Heating-time independent densification of LATP via cold sintering process","authors":"Andrés Mormeneo-Segarra , Thomas Hérisson de Beauvoir , Sergio Ferrer-Nicomedes , Nuria Vicente-Agut , Claude Estournès , Antonio Barba-Juan","doi":"10.1016/j.jeurceramsoc.2025.117252","DOIUrl":"10.1016/j.jeurceramsoc.2025.117252","url":null,"abstract":"<div><div>The Cold Sintering Process has been used to sinter Li<sub>1.3</sub>Al<sub>0.3</sub>Ti<sub>1.7</sub>(PO<sub>4</sub>)<sub>3</sub> powder (LATP) initially mixed with 15 wt% of a solution of acetic acid <span>3 m</span> as Transient Liquid Phase (TLP). The effect of variables such as green density, heating rate, sintering temperature, dwell time and the operating pressure on the densification of LATP <em>via</em> CSP has been thoroughly analysed. The operating pressure shows no effect on the green density above 450 MPa. The heating rates, thus the heating time, do not modify the densification behavior of LATP Solid-State Electrolytes (SSEs) but a decomposition reaction takes place at temperatures above 180 ºC. This reaction depends on the TLP amount still present in the pores, and at higher pressures (P > 450 MPa) this decomposition effect on densification is reduced as the pore volume becomes smaller. For the first time in the CSP, a linear dependence of relative density on temperature is demonstrated.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117252"},"PeriodicalIF":5.8,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172992","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 : 2025-02-01DOI: 10.1016/j.jeurceramsoc.2025.117249
Shixiang Zhou , Feng Zhang , Jin Wu , Jin Su , Kai Liu , Yue Zhang , Changshun Wang , Chunze Yan , Yusheng Shi
Ceramic vat photopolymerization (VPP) has recently emerged as a transformative technology, providing efficient, reliable, and highly customizable methods for fabricating ceramic components with excellent surface quality, precisely controllable structures, and programmable functionality. Despite its widespread adoption, the inherent issue of anisotropic properties, characterized by orientation-dependent features in VPP-manufactured ceramics, remains a significant barrier to broader applications in academic and engineering domains. Due to the complex photocuring behavior of ceramic suspensions and critical post-processing steps such as debinding and sintering, anisotropy in VPP-manufactured ceramics is more intricate compared to other materials. Numerous researches have shown that controlling on the inherent layered microstructure and orientation-dependent property is key for producing high-performance ceramic parts and promoting its industrialization. This review offers a comprehensive analysis of recent advancements in understanding anisotropic behavior in additive-manufactured ceramic components created using VPP. The discussion begins with an exploration of anisotropy formation mechanisms, emphasizing the evolution of the layered microstructure from the photocured ceramic monolayer to fully sintered ceramic parts. It then highlights the latest developments regarding the influence of anisotropy on various properties of VPP-printed ceramics, clarifying the interrelation between material, process, structure, and anisotropic properties. Additionally, strategies for mitigating or exploiting the undesirable anisotropy are critically examined, with a specific focus on the mechanisms underlying each approach. Finally, the review addresses existing challenges and potential directions for future research on anisotropy in VPP-manufactured ceramics.
{"title":"Anisotropy in ceramic vat photopolymerization: Formation mechanisms, influence on properties, and manipulating strategies","authors":"Shixiang Zhou , Feng Zhang , Jin Wu , Jin Su , Kai Liu , Yue Zhang , Changshun Wang , Chunze Yan , Yusheng Shi","doi":"10.1016/j.jeurceramsoc.2025.117249","DOIUrl":"10.1016/j.jeurceramsoc.2025.117249","url":null,"abstract":"<div><div>Ceramic vat photopolymerization (VPP) has recently emerged as a transformative technology, providing efficient, reliable, and highly customizable methods for fabricating ceramic components with excellent surface quality, precisely controllable structures, and programmable functionality. Despite its widespread adoption, the inherent issue of anisotropic properties, characterized by orientation-dependent features in VPP-manufactured ceramics, remains a significant barrier to broader applications in academic and engineering domains. Due to the complex photocuring behavior of ceramic suspensions and critical post-processing steps such as debinding and sintering, anisotropy in VPP-manufactured ceramics is more intricate compared to other materials. Numerous researches have shown that controlling on the inherent layered microstructure and orientation-dependent property is key for producing high-performance ceramic parts and promoting its industrialization. This review offers a comprehensive analysis of recent advancements in understanding anisotropic behavior in additive-manufactured ceramic components created using VPP. The discussion begins with an exploration of anisotropy formation mechanisms, emphasizing the evolution of the layered microstructure from the photocured ceramic monolayer to fully sintered ceramic parts. It then highlights the latest developments regarding the influence of anisotropy on various properties of VPP-printed ceramics, clarifying the interrelation between material, process, structure, and anisotropic properties. Additionally, strategies for mitigating or exploiting the undesirable anisotropy are critically examined, with a specific focus on the mechanisms underlying each approach. Finally, the review addresses existing challenges and potential directions for future research on anisotropy in VPP-manufactured ceramics.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117249"},"PeriodicalIF":5.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377011","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 : 2025-01-31DOI: 10.1016/j.jeurceramsoc.2025.117251
Zhen Wang , Yuan Cheng , Kewei Li , Mengen Hu , Hanwen Zhang , Xian Dang , Ming Li , Xinyang Li , Zhulin Huang , Yue Li , Xiaoye Hu
High quality ceramic powders are crucial for the performance of composite materials, yet preparing powders with good morphology and high crystallinity still faces enormous challenges. Herein we report a topological Archimedean polyhedron of (Zr0.5Hf0.5)B2 nanoparticles were synthesized via a high pressure liquid-phase and coprecipitation co-assisted boro/carbothermal reduction method. A nonclassical crystallization model where both oriented attachment and screw dislocation growth mechanism occur simultaneously. The microstructural evolution during the growth process of borides indicates that the growth mechanism of the new layer on the surface of diborides is mainly explained by the layered structure and trapezoidal profile. The initial growth stage energy of each layer comes from interface defects and lattice mismatches during atomic diffusion processes. The directional attachment of clusters leads to the generation of a large number of dislocations in the system, resulting in the formation of polyhedral structures. Benefiting from the high crystallinity polyhedral morphology, the powder shows excellent oxidation resistance, i.e., the thickness of ceramic oxide layer prepared by Archimedean polyhedron powders is 86.43 μm at 1400 °C for 3 h. This work holds significant importance for the development of new ceramic powders preparation methods and provides a novel approach for studying the performance improvement of ultra-high temperature ceramic materials.
{"title":"Growth mechanism and sintering properties of high crystallinity Archimedean polyhedral (Zr0.5Hf0.5)B2 nanoparticles","authors":"Zhen Wang , Yuan Cheng , Kewei Li , Mengen Hu , Hanwen Zhang , Xian Dang , Ming Li , Xinyang Li , Zhulin Huang , Yue Li , Xiaoye Hu","doi":"10.1016/j.jeurceramsoc.2025.117251","DOIUrl":"10.1016/j.jeurceramsoc.2025.117251","url":null,"abstract":"<div><div>High quality ceramic powders are crucial for the performance of composite materials, yet preparing powders with good morphology and high crystallinity still faces enormous challenges. Herein we report a topological Archimedean polyhedron of (Zr<sub>0.5</sub>Hf<sub>0.5</sub>)B<sub>2</sub> nanoparticles were synthesized <em>via</em> a high pressure liquid-phase and coprecipitation co-assisted boro/carbothermal reduction method. A nonclassical crystallization model where both oriented attachment and screw dislocation growth mechanism occur simultaneously. The microstructural evolution during the growth process of borides indicates that the growth mechanism of the new layer on the surface of diborides is mainly explained by the layered structure and trapezoidal profile. The initial growth stage energy of each layer comes from interface defects and lattice mismatches during atomic diffusion processes. The directional attachment of clusters leads to the generation of a large number of dislocations in the system, resulting in the formation of polyhedral structures. Benefiting from the high crystallinity polyhedral morphology, the powder shows excellent oxidation resistance, <em>i.e.</em>, the thickness of ceramic oxide layer prepared by Archimedean polyhedron powders is 86.43 μm at 1400 °C for 3 h. This work holds significant importance for the development of new ceramic powders preparation methods and provides a novel approach for studying the performance improvement of ultra-high temperature ceramic materials.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117251"},"PeriodicalIF":5.8,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376797","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 : 2025-01-29DOI: 10.1016/j.jeurceramsoc.2025.117244
J. Molera , M. Colomer , O. Vallcorba , T. Pradell
Lead glazes have been coloured and decorated with iron and manganese oxides since ancient times. During firing, these pigments react and form new crystalline compounds such as haematite, andradite, melanotekite, kentrolite, braunite, jacobsite and magnetoplumbite which have been identified in lead-glazed ceramics from the 11th to 17th centuries. To determine the sequence of formation of these pigments, an X-ray powder diffraction experiment was conducted at the ALBA synchrotron up to 928°C with various mixtures. The influence of Al2O3, CaO, and MgO was also studied. The sequence of crystalline phase formation in different systems was established, and laboratory recreations of glazed ceramics at temperatures from 850°C to 1020°C were analysed using optical and electronic microscopy. Understanding the sequence of formation of iron and manganese crystals in lead glazes helps to elucidate ancient production techniques and the final appearance of the glazes.
{"title":"Iron-manganese crystalline phases developed in high lead glazes during firing","authors":"J. Molera , M. Colomer , O. Vallcorba , T. Pradell","doi":"10.1016/j.jeurceramsoc.2025.117244","DOIUrl":"10.1016/j.jeurceramsoc.2025.117244","url":null,"abstract":"<div><div>Lead glazes have been coloured and decorated with iron and manganese oxides since ancient times. During firing, these pigments react and form new crystalline compounds such as haematite, andradite, melanotekite, kentrolite, braunite, jacobsite and magnetoplumbite which have been identified in lead-glazed ceramics from the 11th to 17th centuries. To determine the sequence of formation of these pigments, an X-ray powder diffraction experiment was conducted at the ALBA synchrotron up to 928°C with various mixtures. The influence of Al<sub>2</sub>O<sub>3</sub>, CaO, and MgO was also studied. The sequence of crystalline phase formation in different systems was established, and laboratory recreations of glazed ceramics at temperatures from 850°C to 1020°C were analysed using optical and electronic microscopy. Understanding the sequence of formation of iron and manganese crystals in lead glazes helps to elucidate ancient production techniques and the final appearance of the glazes.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117244"},"PeriodicalIF":5.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143360801","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 : 2025-01-29DOI: 10.1016/j.jeurceramsoc.2025.117246
Xiong Xiao , Linpeng Zheng , Qian Li , Chunhua Chen , Duanwei He , Xiuyan Wei , Zuguang Hu , Jianyun Yang , Guodong (David) Zhan
Chemical vapour deposition (CVD) rates are limited, making the preparation of thick diamonds challenging. We propose an efficient high pressure high temperature (HPHT) welding method for polycrystalline CVD diamond films. Multiple layers of CVD polycrystalline diamond films are welded into a monolithic structure under 15 GPa and 2100 °C. HPHT treated samples have an extremely high bond strength and the hardness of the weld layer exceeds 120 GPa. Microstructural analyses suggest the mechanism of HPHT welding: laser treatment transforms the carbon atoms on the CVD diamond film surface from SP3 to SP2 hybridization, forming a non-diamond-carbon/diamond coherent interface. Under HPHT conditions, the carbon atoms are again transformed from SP2 to SP3 hybridization, forming a strong interlayer bond through diffusion at the coherent interface. This method provides a new approach for rapidly preparing diamond bulk materials.
{"title":"HPHT welding of CVD polycrystalline diamond films","authors":"Xiong Xiao , Linpeng Zheng , Qian Li , Chunhua Chen , Duanwei He , Xiuyan Wei , Zuguang Hu , Jianyun Yang , Guodong (David) Zhan","doi":"10.1016/j.jeurceramsoc.2025.117246","DOIUrl":"10.1016/j.jeurceramsoc.2025.117246","url":null,"abstract":"<div><div>Chemical vapour deposition (CVD) rates are limited, making the preparation of thick diamonds challenging. We propose an efficient high pressure high temperature (HPHT) welding method for polycrystalline CVD diamond films. Multiple layers of CVD polycrystalline diamond films are welded into a monolithic structure under 15 GPa and 2100 °C. HPHT treated samples have an extremely high bond strength and the hardness of the weld layer exceeds 120 GPa. Microstructural analyses suggest the mechanism of HPHT welding: laser treatment transforms the carbon atoms on the CVD diamond film surface from SP3 to SP2 hybridization, forming a non-diamond-carbon/diamond coherent interface. Under HPHT conditions, the carbon atoms are again transformed from SP2 to SP3 hybridization, forming a strong interlayer bond through diffusion at the coherent interface. This method provides a new approach for rapidly preparing diamond bulk materials.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117246"},"PeriodicalIF":5.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143358622","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 : 2025-01-29DOI: 10.1016/j.jeurceramsoc.2025.117248
Ce Sun , Song Zhang , Zimian Xu , Junchao He , Lihong Wu , Dongsheng Gu , Meijun Yang , Peng Chen , Xiao Han , Lixia Yang , Kai Liu , Yusheng Shi
The Csf/SiC composites are fabricated by Laser powder bed fusion/liquid silicon infiltration (LPBF/LSI). To prevent the Csf from being eroded by molten Si, and optimize the interface between the fiber and matrix, a pyrolytic carbon-silicon carbide (PyC-SiC) double-coated layer is synthesized on the surface of Csf. The SiC layer prevents the diffusion of molten Si, thereby shielding fibers from erosion. The PyC layer can form a weak bonding interface between the matrix and fibers, facilitating fiber extraction at crack tips during material fracture. The double-layer coating's dual action mechanism of fiber damage prevention and crack propagation inhibition significantly enhances the strength and fracture toughness of Csf/SiC composites. Csf/SiC composites with double-layer coated fibers exhibit a maximum bending strength of 257.11 MPa and a maximum fracture toughness of 3.60 MPa·m1/2, marking respective improvements of 8.51 % and 16.12 % compared to the Csf/SiC composites with original fibers.
{"title":"Double-layer coated Csf/SiC composite fabricated by LPBF/LSI with improved mechanical properties through fiber damage prevention and crack propagation inhibition","authors":"Ce Sun , Song Zhang , Zimian Xu , Junchao He , Lihong Wu , Dongsheng Gu , Meijun Yang , Peng Chen , Xiao Han , Lixia Yang , Kai Liu , Yusheng Shi","doi":"10.1016/j.jeurceramsoc.2025.117248","DOIUrl":"10.1016/j.jeurceramsoc.2025.117248","url":null,"abstract":"<div><div>The C<sub>sf</sub>/SiC composites are fabricated by Laser powder bed fusion/liquid silicon infiltration (LPBF/LSI). To prevent the C<sub>sf</sub> from being eroded by molten Si, and optimize the interface between the fiber and matrix, a pyrolytic carbon-silicon carbide (PyC-SiC) double-coated layer is synthesized on the surface of C<sub>sf</sub>. The SiC layer prevents the diffusion of molten Si, thereby shielding fibers from erosion. The PyC layer can form a weak bonding interface between the matrix and fibers, facilitating fiber extraction at crack tips during material fracture. The double-layer coating's dual action mechanism of fiber damage prevention and crack propagation inhibition significantly enhances the strength and fracture toughness of C<sub>sf</sub>/SiC composites. C<sub>sf</sub>/SiC composites with double-layer coated fibers exhibit a maximum bending strength of 257.11 MPa and a maximum fracture toughness of 3.60 MPa·m<sup>1/2</sup>, marking respective improvements of 8.51 % and 16.12 % compared to the C<sub>sf</sub>/SiC composites with original fibers.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 7","pages":"Article 117248"},"PeriodicalIF":5.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143358623","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 : 2025-01-29DOI: 10.1016/j.jeurceramsoc.2025.117247
Robert Golden , Elizabeth Opila
The diffusivity of oxygen in environmental barrier coating (EBC) materials must be sufficiently low to limit the oxidation of the underlying silicon bond coat and silicon carbide ceramic matrix composite (SiC CMC). Yttrium silicates have been proposed as candidate EBC materials however there are limited oxygen diffusivity data available. In this study, oxygen diffusion coefficients for polycrystalline Y2Si2O7 and Y2SiO5 were determined using the oxygen tracer diffusion technique. The 18O diffusion concentration profiles were measured after exposure at temperatures of 1000 – 1300°C using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Oxygen tracer diffusion and surface exchange coefficients were obtained by fitting the semi-infinite solution of the diffusion equation to the concentration profiles. Oxygen diffusion and surface exchange coefficients in yttrium silicates ranged from 10−14 – 10−12 cm2/s and 10−10 – 10−8 cm/s respectively. Fast transport of 18O along grain boundaries, pores and in some grain orientations (anisotropic diffusion) was observed. Results are utilized to assess the viability of yttrium silicates and other rare-earth silicates as EBC materials for SiC CMCs.
{"title":"Oxygen tracer diffusion in yttrium silicates","authors":"Robert Golden , Elizabeth Opila","doi":"10.1016/j.jeurceramsoc.2025.117247","DOIUrl":"10.1016/j.jeurceramsoc.2025.117247","url":null,"abstract":"<div><div>The diffusivity of oxygen in environmental barrier coating (EBC) materials must be sufficiently low to limit the oxidation of the underlying silicon bond coat and silicon carbide ceramic matrix composite (SiC CMC). Yttrium silicates have been proposed as candidate EBC materials however there are limited oxygen diffusivity data available. In this study, oxygen diffusion coefficients for polycrystalline Y<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> and Y<sub>2</sub>SiO<sub>5</sub> were determined using the oxygen tracer diffusion technique. The <sup>18</sup>O diffusion concentration profiles were measured after exposure at temperatures of 1000 – 1300°C using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Oxygen tracer diffusion and surface exchange coefficients were obtained by fitting the semi-infinite solution of the diffusion equation to the concentration profiles. Oxygen diffusion and surface exchange coefficients in yttrium silicates ranged from 10<sup>−14</sup> – 10<sup>−12</sup> cm<sup>2</sup>/s and 10<sup>−10</sup> – 10<sup>−8</sup> cm/s respectively. Fast transport of <sup>18</sup>O along grain boundaries, pores and in some grain orientations (anisotropic diffusion) was observed. Results are utilized to assess the viability of yttrium silicates and other rare-earth silicates as EBC materials for SiC CMCs.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 8","pages":"Article 117247"},"PeriodicalIF":5.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429136","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 : 2025-01-29DOI: 10.1016/j.jeurceramsoc.2025.117243
Baokuo Nie , Zhongkan Ren , Tongyang Li , Huaguo Tang , Yuan Yu , Lujie Wang , Zhuhui Qiao
In all-brittle systems, inducing rising crack-resistance curves (R-curve) remains challenging due to high interface strength, especially introducing a stiffer additive phase. Nevertheless, we connected stiff phase TiC as network structure in Si3N4 matrix and facilitated their in-situ reaction. Morphological characterisation indicates that a submicron SiC network with micro/nano-pores was formed in the TiC network, which provides a continuous “channel” to induce the deflection of cracks within stiff network and results in rising R-curves. In samples with direct TiN introduction, cracks are likely to be blocked by the TiN network rather than propagating along the network. Finally, we deduced the formation process of SiC network with micro/nano pores based on the morphological characterisation and the reaction mechanism between Si3N4 and TiC. These findings provide valuable insights into the structural and component design associated with toughening efforts for ceramic composites.
{"title":"Investigation of inducing rising R-curves in all-brittle systems with stiff network structure","authors":"Baokuo Nie , Zhongkan Ren , Tongyang Li , Huaguo Tang , Yuan Yu , Lujie Wang , Zhuhui Qiao","doi":"10.1016/j.jeurceramsoc.2025.117243","DOIUrl":"10.1016/j.jeurceramsoc.2025.117243","url":null,"abstract":"<div><div>In all-brittle systems, inducing rising crack-resistance curves (R-curve) remains challenging due to high interface strength, especially introducing a stiffer additive phase. Nevertheless, we connected stiff phase TiC as network structure in Si<sub>3</sub>N<sub>4</sub> matrix and facilitated their in-situ reaction. Morphological characterisation indicates that a submicron SiC network with micro/nano-pores was formed in the TiC network, which provides a continuous “channel” to induce the deflection of cracks within stiff network and results in rising R-curves. In samples with direct TiN introduction, cracks are likely to be blocked by the TiN network rather than propagating along the network. Finally, we deduced the formation process of SiC network with micro/nano pores based on the morphological characterisation and the reaction mechanism between Si<sub>3</sub>N<sub>4</sub> and TiC. These findings provide valuable insights into the structural and component design associated with toughening efforts for ceramic composites.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 8","pages":"Article 117243"},"PeriodicalIF":5.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403459","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 : 2025-01-29DOI: 10.1016/j.jeurceramsoc.2025.117242
Woo-Jin Choi , Jeong-Woo Sun , Temesgen Tadeyos Zate , Sang-Goo Lee , Yoon-Sang Jeong , Wook Jo
Enhanced temperature stability and dielectric permittivity of piezoelectric materials are desirable for ultrasound-based transducer applications because the self-heating of devices during operation degrades piezoelectric properties and electrical impedance mismatching limits power transfer. To address these issues, (1−x)Pb(In1/2Nb1/2)O3−0.05Pb(Mg1/3Nb2/3)O3−xPbTiO3 ceramics near the morphotropic phase boundary were synthesized using solid-state reaction method. These compositions exhibited mixed rhombohedral and tetragonal perovskite structures, and the tetragonal phase fraction increased with increasing x. The εr of the rhombohedral phase decreased, while that of the tetragonal phase increased after application of an AC electric field, and the tetragonal phase contributed more to d33 than the rhombohedral phase. The rhombohedral phase gradually depolarized with increasing annealing temperature. The εr can be enhanced by utilizing the advantage of the depolarized rhombohedral phase without significantly sacrificing piezoelectric properties. This method has potential as a strategy to alleviate electrical impedance mismatching, enhancing the imaging performance of transducers for ultrasound-based medical diagnosis.
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