Pub Date : 2024-10-30DOI: 10.1016/j.jeurceramsoc.2024.117038
Yanfei Wang , Weiran Zhang , Jinping Du, Duan Li, Rongjun Liu
It is urgent to develop thermal barrier coating (TBC) topcoat materials with ultra-low thermal conductivities for next-generation gas turbine engines. A novel pyrochlore-based single-phased ceramic, tuned by codoping of lanthanum zirconate, (La1-xYx)2(Zr1-yCey)2O7, has been synthesized from the solid state reaction method. The thermal conductivity of (La1-xYx)2(Zr1-yCey)2O7 not only exhibits a temperature-independent trend but also reaches as low as 0.93 W·m−1·K−1, a value that is lowest of fully dense crystalline solids in open literature, attributing to the following two combined effects. The first is the strong scattering of phonons by small-sized Y3+ cations occupying the oversized atomic cages formed by the distinctive pyrochlore structure. The second is the lattice softening effects arising from larger-sized Ce4+ substituting Zr4+ cations. The above two effects act in concert and thus form a glasslike and ultra-low thermal conductivity of (La1-xYx)2(Zr1-yCey)2O7 solid solutions, which is ideal for next-generation TBC topcoat applications.
{"title":"The ultra-low glasslike thermal conductivities of Y3+- and Ce4+- codoped lanthanum zirconate pyrochlores for potential thermal barrier coating applications","authors":"Yanfei Wang , Weiran Zhang , Jinping Du, Duan Li, Rongjun Liu","doi":"10.1016/j.jeurceramsoc.2024.117038","DOIUrl":"10.1016/j.jeurceramsoc.2024.117038","url":null,"abstract":"<div><div>It is urgent to develop thermal barrier coating (TBC) topcoat materials with ultra-low thermal conductivities for next-generation gas turbine engines. A novel pyrochlore-based single-phased ceramic, tuned by codoping of lanthanum zirconate, (La<sub>1-x</sub>Y<sub>x</sub>)<sub>2</sub>(Zr<sub>1-y</sub>Ce<sub>y</sub>)<sub>2</sub>O<sub>7</sub>, has been synthesized from the solid state reaction method. The thermal conductivity of (La<sub>1-x</sub>Y<sub>x</sub>)<sub>2</sub>(Zr<sub>1-y</sub>Ce<sub>y</sub>)<sub>2</sub>O<sub>7</sub> not only exhibits a temperature-independent trend but also reaches as low as 0.93 W·m<sup>−1</sup>·K<sup>−1</sup>, a value that is lowest of fully dense crystalline solids in open literature, attributing to the following two combined effects. The first is the strong scattering of phonons by small-sized Y<sup>3+</sup> cations occupying the oversized atomic cages formed by the distinctive pyrochlore structure. The second is the lattice softening effects arising from larger-sized Ce<sup>4+</sup> substituting Zr<sup>4+</sup> cations. The above two effects act in concert and thus form a glasslike and ultra-low thermal conductivity of (La<sub>1-x</sub>Y<sub>x</sub>)<sub>2</sub>(Zr<sub>1-y</sub>Ce<sub>y</sub>)<sub>2</sub>O<sub>7</sub> solid solutions, which is ideal for next-generation TBC topcoat applications.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117038"},"PeriodicalIF":5.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593280","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}
Dense SiC-(10-30 vol%) ZrN composites were developed using spark plasma sintering with AlN-Y2O3 additives at 1800 °C for 5 min in nitrogen atmosphere. The nascent oxide present on ZrN surface reduces liquid phase formation temperature, facilitating improved densification of SiC ceramics. Mechanical properties were retained, and electrical conductivity increased with ZrN addition. To demonstrate a rapid and low-cost machining alternative for SiC ceramics, SiC-ZrN composites were successfully cut using wire-EDM. The tribological potential of novel electrical discharge machinable SiC-ZrN composite disk against SiC ball at various conditions of reciprocating sliding contacts was investigated. Friction is less affected by reinforcement content at room temperature (25 ℃) but significant change is observed at high temperature (600 ℃). Minimum one order of lower wear rate is reported with an increase in temperature from 25 ℃ to 600 ℃. The major wear mechanism changed from abrasion to tribo oxidation with increase in temperature.
{"title":"Development of electrical discharge machinable SiC-ZrN composites: Unveiling high temperature sliding wear resistance","authors":"Chodisetti Surya Prakasarao , Irfan Nadeem , Mitjan Kalin , B. Venkata Manoj Kumar","doi":"10.1016/j.jeurceramsoc.2024.117040","DOIUrl":"10.1016/j.jeurceramsoc.2024.117040","url":null,"abstract":"<div><div>Dense SiC-(10-30 vol%) ZrN composites were developed using spark plasma sintering with AlN-Y<sub>2</sub>O<sub>3</sub> additives at 1800 °C for 5 min in nitrogen atmosphere. The nascent oxide present on ZrN surface reduces liquid phase formation temperature, facilitating improved densification of SiC ceramics. Mechanical properties were retained, and electrical conductivity increased with ZrN addition. To demonstrate a rapid and low-cost machining alternative for SiC ceramics, SiC-ZrN composites were successfully cut using wire-EDM. The tribological potential of novel electrical discharge machinable SiC-ZrN composite disk against SiC ball at various conditions of reciprocating sliding contacts was investigated. Friction is less affected by reinforcement content at room temperature (25 ℃) but significant change is observed at high temperature (600 ℃). Minimum one order of lower wear rate is reported with an increase in temperature from 25 ℃ to 600 ℃. The major wear mechanism changed from abrasion to tribo oxidation with increase in temperature.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117040"},"PeriodicalIF":5.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578410","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 : 2024-10-30DOI: 10.1016/j.jeurceramsoc.2024.117041
Ruifeng Wu , Yang Zhou , Yue Xian , Yafei Liu , Hao Sun , Aimin Chang , Bo Zhang
In this work, a series of CaCu3Ti4O12-LaMn1-xFexO3 sandwich and core-shell structured ceramics were prepared by using the conventional solid-state method. For these structures, LaMn1-xFexO3 is encapsulated by the CaCu3Ti4O12 (CCTO) layer as a core and interlayer. These ceramics demonstrate high sensitivity with material constants (B) ranging from 7391 to 9786 K and temperature coefficients up to −7.03 %. In addition, Fe3+ doping optimizes the electronic structure of LaMnO3 (LMO) and enhances the Jahn-Taylor coupling and charge localization, thus leading to an increase in the material constant. Furthermore, the core-shell ceramics of CCTO-LMO (Co-LMO) have a high dielectric constant of 16731 at 1 kHz, which exceeds that of the CCTO samples. This enhancement can be attributed to the increase in potential differences caused by the additional carriers. The proposed schemes in this work have important implications for regulating the thermal sensitivity and permittivity of CCTO-based multifunctional coupled electronics.
{"title":"High thermal sensitivity and dielectric constants in CaCu3Ti4O12-LaMn1-xFexO3 composite ceramics by designing sandwich and core-shell structure","authors":"Ruifeng Wu , Yang Zhou , Yue Xian , Yafei Liu , Hao Sun , Aimin Chang , Bo Zhang","doi":"10.1016/j.jeurceramsoc.2024.117041","DOIUrl":"10.1016/j.jeurceramsoc.2024.117041","url":null,"abstract":"<div><div>In this work, a series of CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub>-LaMn<sub>1-<em>x</em></sub>Fe<sub><em>x</em></sub>O<sub>3</sub> sandwich and core-shell structured ceramics were prepared by using the conventional solid-state method. For these structures, LaMn<sub>1-<em>x</em></sub>Fe<sub><em>x</em></sub>O<sub>3</sub> is encapsulated by the CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> (CCTO) layer as a core and interlayer. These ceramics demonstrate high sensitivity with material constants (<em>B</em>) ranging from 7391 to 9786 K and temperature coefficients up to −7.03 %. In addition, Fe<sup>3+</sup> doping optimizes the electronic structure of LaMnO<sub>3</sub> (LMO) and enhances the Jahn-Taylor coupling and charge localization, thus leading to an increase in the material constant. Furthermore, the core-shell ceramics of CCTO-LMO (Co-LMO) have a high dielectric constant of 16731 at 1 kHz, which exceeds that of the CCTO samples. This enhancement can be attributed to the increase in potential differences caused by the additional carriers. The proposed schemes in this work have important implications for regulating the thermal sensitivity and permittivity of CCTO-based multifunctional coupled electronics.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117041"},"PeriodicalIF":5.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572810","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 : 2024-10-29DOI: 10.1016/j.jeurceramsoc.2024.117037
Josef Schlacher, Fabian Stücklberger, Abdullah Jabr, Raul Bermejo
Hertzian contact damage upon spherical indentation is investigated in alumina-based ceramics designed with embedded textured compressive layers. The effect of the location of the embedded layer and the testing configuration (parallel or normal to the layer orientation) on the sub-surface damage evolution is explored. An acoustic emission system for crack detection and post-mortem cross sectioning are employed to evaluate the onset and extension of damage in the different samples. Distinct acoustic signals detected at different contact loads are correlated with the onset of the ring crack, cone crack propagation and quasi-plastic deformation within the textured layer. The distinct damage mechanisms are influenced by the location of the embedded textured compressive layer and the loading orientation with respect to the layers. The design of layered ceramics for contact applications should consider the loading orientation as well as the contact stress field with respect to the “protective” layer to enhance damage tolerance.
{"title":"Contact damage response of alumina-based layered architectures under different loading configurations","authors":"Josef Schlacher, Fabian Stücklberger, Abdullah Jabr, Raul Bermejo","doi":"10.1016/j.jeurceramsoc.2024.117037","DOIUrl":"10.1016/j.jeurceramsoc.2024.117037","url":null,"abstract":"<div><div>Hertzian contact damage upon spherical indentation is investigated in alumina-based ceramics designed with embedded textured compressive layers. The effect of the location of the embedded layer and the testing configuration (parallel or normal to the layer orientation) on the sub-surface damage evolution is explored. An acoustic emission system for crack detection and post-mortem cross sectioning are employed to evaluate the onset and extension of damage in the different samples. Distinct acoustic signals detected at different contact loads are correlated with the onset of the ring crack, cone crack propagation and quasi-plastic deformation within the textured layer. The distinct damage mechanisms are influenced by the location of the embedded textured compressive layer and the loading orientation with respect to the layers. The design of layered ceramics for contact applications should consider the loading orientation as well as the contact stress field with respect to the “protective” layer to enhance damage tolerance.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117037"},"PeriodicalIF":5.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561489","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 : 2024-10-29DOI: 10.1016/j.jeurceramsoc.2024.117028
Yuxin Tang , Song Hu , Zhenhai Xue , Guohong Zhou
Efficient thermal management is essential to reduce hot spot temperature of high-power opto-electronic components and improve their working efficiency. In this work, AlN ceramics with high density and thermal conductivity properties were fabricated using a joint process of digital light processing (DLP) 3D printing and micro-pressure-assisted sintering method. Effects of solid loading on microstructure evolution and thermal properties of the ceramics were systematically discussed. AlN ceramic mini-channel heat sinks were designed and fabricated using the optimized DLP 3D printing and sintering parameters. The thermal management performances of the ceramic heat sinks were evaluated by investigating the optoelectronic property of the encapsulated laser diode module. Results indicated that the laser diode module could be long-timely operated at full driven power. This study provided a new strategy for fabricating high performance AlN ceramics with complex configurations and highlighted the technical potential of AlN ceramic heat sink with compact coolant channels.
{"title":"Influence of solid loading on microstructure evolution and thermal conductivity of aluminum nitride ceramics fabricated by digital light processing 3D printing","authors":"Yuxin Tang , Song Hu , Zhenhai Xue , Guohong Zhou","doi":"10.1016/j.jeurceramsoc.2024.117028","DOIUrl":"10.1016/j.jeurceramsoc.2024.117028","url":null,"abstract":"<div><div>Efficient thermal management is essential to reduce hot spot temperature of high-power opto-electronic components and improve their working efficiency. In this work, AlN ceramics with high density and thermal conductivity properties were fabricated using a joint process of digital light processing (DLP) 3D printing and micro-pressure-assisted sintering method. Effects of solid loading on microstructure evolution and thermal properties of the ceramics were systematically discussed. AlN ceramic mini-channel heat sinks were designed and fabricated using the optimized DLP 3D printing and sintering parameters. The thermal management performances of the ceramic heat sinks were evaluated by investigating the optoelectronic property of the encapsulated laser diode module. Results indicated that the laser diode module could be long-timely operated at full driven power. This study provided a new strategy for fabricating high performance AlN ceramics with complex configurations and highlighted the technical potential of AlN ceramic heat sink with compact coolant channels.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117028"},"PeriodicalIF":5.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554143","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}
Highly transparent ceramics based on LuAG with erbium content ranging from 1 to 50 at% were synthesized from powders prepared via chemical precipitation in an aqueous solution. The impact of hot isostatic pressing on the optical properties of these ceramics was investigated. It was demonstrated that employing hot isostatic pressing enhances the optical transmittance of LuAG:Er ceramics. The influence of erbium concentration on the average grain size of the ceramics was also examined. Additionally, temperature-dependent thermal diffusivity profiles of LuAG:Er ceramics as a function of erbium content were analyzed. Erbium concentrations yielding the highest luminescence intensity in spectral ranges around ∼1.5–1.6 μm and ∼2.7 μm were determined.
{"title":"Fabrication and characterization of LuAG: Er ceramics with high optical transmission","authors":"A.A. Kravtsov , O.M. Chapura , V.A. Tarala , E.V. Medyanik , L.V. Tarala , V.E. Suprunchuk , F.F. Malyavin , S.V. Kuznetsov , V.S. Tsvetkov , E.A. Dobretsova , Yu.L. Kalachev , V.A. Lapin","doi":"10.1016/j.jeurceramsoc.2024.117033","DOIUrl":"10.1016/j.jeurceramsoc.2024.117033","url":null,"abstract":"<div><div>Highly transparent ceramics based on LuAG with erbium content ranging from 1 to 50 at% were synthesized from powders prepared via chemical precipitation in an aqueous solution. The impact of hot isostatic pressing on the optical properties of these ceramics was investigated. It was demonstrated that employing hot isostatic pressing enhances the optical transmittance of LuAG:Er ceramics. The influence of erbium concentration on the average grain size of the ceramics was also examined. Additionally, temperature-dependent thermal diffusivity profiles of LuAG:Er ceramics as a function of erbium content were analyzed. Erbium concentrations yielding the highest luminescence intensity in spectral ranges around ∼1.5–1.6 μm and ∼2.7 μm were determined.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117033"},"PeriodicalIF":5.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561492","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 : 2024-10-29DOI: 10.1016/j.jeurceramsoc.2024.117036
Atta Ullah, Haribabu Palneedi, Sang-Chae Jeon
The cold sintering process (CSP) is utilized as a pre-treatment to densify BaTiO3 before subsequent conventional sintering (TS). A comparison between two different processing routes, with or without the CSP pre-treatment (CSP + TS or TS). After CSP at 225 °C and subsequent TS at 1000 °C, a high relative density (e.g., 96.86 % TD) was obtained with an average grain size of 1.52 μm, while corresponding outcomes of 60.56 % TD and 0.29 μm were obtained in the sample without the CSP pre-treatment. This dramatic improvement was evident in a wide temperature range from 900 to 1200 °C, leading to superior dielectric properties to the TS samples in a frequency range from 1 kHz to 1 MHz. The enhanced performance is attributable to reduced secondary phases, an enhanced relative density, and the optimal grain size realized by modifying the processing temperatures, highlighting the benefits of the CSP pre-treatment.
{"title":"Enhanced densification and dielectric properties of BaTiO3 through a cold-sintering pre-treatment","authors":"Atta Ullah, Haribabu Palneedi, Sang-Chae Jeon","doi":"10.1016/j.jeurceramsoc.2024.117036","DOIUrl":"10.1016/j.jeurceramsoc.2024.117036","url":null,"abstract":"<div><div>The cold sintering process (CSP) is utilized as a pre-treatment to densify BaTiO<sub>3</sub> before subsequent conventional sintering (TS). A comparison between two different processing routes, with or without the CSP pre-treatment (CSP + TS or TS). After CSP at 225 °C and subsequent TS at 1000 °C, a high relative density (e.g., 96.86 % TD) was obtained with an average grain size of 1.52 μm, while corresponding outcomes of 60.56 % TD and 0.29 μm were obtained in the sample without the CSP pre-treatment. This dramatic improvement was evident in a wide temperature range from 900 to 1200 °C, leading to superior dielectric properties to the TS samples in a frequency range from 1 kHz to 1 MHz. The enhanced performance is attributable to reduced secondary phases, an enhanced relative density, and the optimal grain size realized by modifying the processing temperatures, highlighting the benefits of the CSP pre-treatment.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117036"},"PeriodicalIF":5.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561493","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 : 2024-10-28DOI: 10.1016/j.jeurceramsoc.2024.117026
Yang Lu , Jian Sun , Guanghua Liu , Wei Liu , Xiangyang Liu , Wei Pan , Chunlei Wan
To fulfill the multi-functional requirements of advanced thermal barrier coatings, composite oxides are emerging as promising candidates due to their enhanced thermal and mechanical properties. Although numerous composite materials have been developed, a comprehensive investigation of their microstructure and property evolution is still lacking. In this study, we conducted a comprehensive investigation of the microstructure and property evolution of the Gd3NbO7-GdNbO4 composite thermal barrier coating as a case study. The as-sprayed Gd3NbO7-GdNbO4 coating was verified to possess a single fluorite phase with a composition of NbxGd(1-x)O(1.5+x), which is a metastable phase. After heat treatment, the monoclinic GdNbO4 phase precipitated without altering the coating microstructure. During high-temperature thermal exposure, rapid sintering occurred, accompanied by grain coarsening and pore healing, leading to an increase in hardness and toughness. The toughness of the Gd3NbO7-GdNbO4 coating was higher than that of rare earth zirconates due to the presence of multiple toughening mechanisms. Additionally, a low thermal conductivity of 1.33 W/(m·K) was achieved for the Gd3NbO7-GdNbO4 coating due to rapid sintering. Notably, there were no abrupt changes in the CTE curves during the heating process, which is crucial for thermal barrier coatings. The CTE reaches 11.0×10−6 K−1 at 1300 °C, which is close to YSZ, indicating that the Gd3NbO7-GdNbO4 coating is suitable for advanced thermal barrier coatings.
{"title":"Microstructure and property evolution of Gd3NbO7-GdNbO4 composite thermal barrier coating","authors":"Yang Lu , Jian Sun , Guanghua Liu , Wei Liu , Xiangyang Liu , Wei Pan , Chunlei Wan","doi":"10.1016/j.jeurceramsoc.2024.117026","DOIUrl":"10.1016/j.jeurceramsoc.2024.117026","url":null,"abstract":"<div><div>To fulfill the multi-functional requirements of advanced thermal barrier coatings, composite oxides are emerging as promising candidates due to their enhanced thermal and mechanical properties. Although numerous composite materials have been developed, a comprehensive investigation of their microstructure and property evolution is still lacking. In this study, we conducted a comprehensive investigation of the microstructure and property evolution of the Gd<sub>3</sub>NbO<sub>7</sub>-GdNbO<sub>4</sub> composite thermal barrier coating as a case study. The as-sprayed Gd<sub>3</sub>NbO<sub>7</sub>-GdNbO<sub>4</sub> coating was verified to possess a single fluorite phase with a composition of Nb<sub>x</sub>Gd<sub>(1-x)</sub>O<sub>(1.5+x)</sub>, which is a metastable phase. After heat treatment, the monoclinic GdNbO<sub>4</sub> phase precipitated without altering the coating microstructure. During high-temperature thermal exposure, rapid sintering occurred, accompanied by grain coarsening and pore healing, leading to an increase in hardness and toughness. The toughness of the Gd<sub>3</sub>NbO<sub>7</sub>-GdNbO<sub>4</sub> coating was higher than that of rare earth zirconates due to the presence of multiple toughening mechanisms. Additionally, a low thermal conductivity of 1.33 W/(m·K) was achieved for the Gd<sub>3</sub>NbO<sub>7</sub>-GdNbO<sub>4</sub> coating due to rapid sintering. Notably, there were no abrupt changes in the CTE curves during the heating process, which is crucial for thermal barrier coatings. The CTE reaches 11.0×10<sup>−6</sup> K<sup>−1</sup> at 1300 °C, which is close to YSZ, indicating that the Gd<sub>3</sub>NbO<sub>7</sub>-GdNbO<sub>4</sub> coating is suitable for advanced thermal barrier coatings.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117026"},"PeriodicalIF":5.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658224","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 : 2024-10-28DOI: 10.1016/j.jeurceramsoc.2024.117030
Lexing Liang , Junjing Duan , Cong Zhang , Heqi Zhang , Kailei Lu , Yanli Shi , Jianqi Qi , Tiecheng Lu
Transparent Gd2Zr2O7 (GZO) ceramics show significant potential for radiation detection and nuclear energy applications. However, scalable production through cost-effective solid-state vacuum sintering is challenging due to the material's high melting point and low thermal conductivity. This study introduces a novel approach by incorporating excess Gd to increase lattice defects, such as cation disorder and oxygen vacancies, which have low formation energy. This strategy lowers the energy barrier for ion diffusion, enhances material migration during sintering, and promotes the elimination of residual pores, leading to high densification. We examined the densification behavior of GZO compositions with varying Gd content (Gd1.8Zr2O6.7 to Gd2.5Zr2O7.75) during vacuum sintering at 1450°C to 1900°C, focusing on phase transformation, grain growth, and pore elimination. Notably, the optimal sample achieved 78.3 % transmittance, approaching the theoretical maximum. These findings offer a promising route for the large-scale production and commercialization of transparent GZO ceramics for advanced radiation applications.
{"title":"Promoting transparency: Defect-driven sintering of Gd2Zr2O7 ceramics for advanced radiation applications","authors":"Lexing Liang , Junjing Duan , Cong Zhang , Heqi Zhang , Kailei Lu , Yanli Shi , Jianqi Qi , Tiecheng Lu","doi":"10.1016/j.jeurceramsoc.2024.117030","DOIUrl":"10.1016/j.jeurceramsoc.2024.117030","url":null,"abstract":"<div><div>Transparent Gd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> (GZO) ceramics show significant potential for radiation detection and nuclear energy applications. However, scalable production through cost-effective solid-state vacuum sintering is challenging due to the material's high melting point and low thermal conductivity. This study introduces a novel approach by incorporating excess Gd to increase lattice defects, such as cation disorder and oxygen vacancies, which have low formation energy. This strategy lowers the energy barrier for ion diffusion, enhances material migration during sintering, and promotes the elimination of residual pores, leading to high densification. We examined the densification behavior of GZO compositions with varying Gd content (Gd<sub>1.8</sub>Zr<sub>2</sub>O<sub>6.7</sub> to Gd<sub>2.5</sub>Zr<sub>2</sub>O<sub>7.75</sub>) during vacuum sintering at 1450°C to 1900°C, focusing on phase transformation, grain growth, and pore elimination. Notably, the optimal sample achieved 78.3 % transmittance, approaching the theoretical maximum. These findings offer a promising route for the large-scale production and commercialization of transparent GZO ceramics for advanced radiation applications.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117030"},"PeriodicalIF":5.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142577801","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 : 2024-10-28DOI: 10.1016/j.jeurceramsoc.2024.117025
Minwook Kim , Unseo Kim , Seon-Gyu Kim , Yunsang Kwak , Sung-Soo Ryu , Jaehun Cho
Ultrafast high-temperature sintering (UHS) has received significant attention due to its effectiveness in consolidating ceramics in a very rapid manner. However, the application of UHS to non-oxide materials has been limited due to their extremely low sinterability. In this study, the UHS technique was applied to AlN to demonstrate its applicability and examine the resulting microstructure evolution and mechanical properties. High densification was achieved using electric currents of 47 A, 50 A, and 53 A for 240 s, with corresponding specimen temperatures of 1807.5 °C, 1872.8 °C, and 1935.6 °C. Vickers hardness increases up to 240 s but decreases at 300 s due to grain growth and sublimation of secondary phases. Fracture toughness decreases with larger grain sizes showing the inverse relationship between grain size and toughness. This study demonstrates that UHS is applicable to non-oxide ceramics, which offers significant potential for energy savings and rapid processing in non-oxide ceramic manufacturing.
{"title":"Ultrafast high-temperature sintering of aluminum nitride","authors":"Minwook Kim , Unseo Kim , Seon-Gyu Kim , Yunsang Kwak , Sung-Soo Ryu , Jaehun Cho","doi":"10.1016/j.jeurceramsoc.2024.117025","DOIUrl":"10.1016/j.jeurceramsoc.2024.117025","url":null,"abstract":"<div><div>Ultrafast high-temperature sintering (UHS) has received significant attention due to its effectiveness in consolidating ceramics in a very rapid manner. However, the application of UHS to non-oxide materials has been limited due to their extremely low sinterability. In this study, the UHS technique was applied to AlN to demonstrate its applicability and examine the resulting microstructure evolution and mechanical properties. High densification was achieved using electric currents of 47 A, 50 A, and 53 A for 240 s, with corresponding specimen temperatures of 1807.5 °C, 1872.8 °C, and 1935.6 °C. Vickers hardness increases up to 240 s but decreases at 300 s due to grain growth and sublimation of secondary phases. Fracture toughness decreases with larger grain sizes showing the inverse relationship between grain size and toughness. This study demonstrates that UHS is applicable to non-oxide ceramics, which offers significant potential for energy savings and rapid processing in non-oxide ceramic manufacturing.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 117025"},"PeriodicalIF":5.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572808","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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