{"title":"Microscale rising R-curve behavior of silicon nitride ceramics","authors":"Takahiro Saito, Tatsuki Ohji, Takuma Takahashi, Motoyuki Iijima, Junichi Tatami","doi":"10.1111/jace.20477","DOIUrl":"https://doi.org/10.1111/jace.20477","url":null,"abstract":"<p>This study investigated <i>R-</i>curve behavior when a crack extended several 100 nm for Y<sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub> doped Si<sub>3</sub>N<sub>4</sub> ceramics, using single-edge notched microcantilever beam specimens. The serrate or sawtooth behavior was observed around the maximum load of the load-displacement diagram, indicating the repetition of crack initiation and arrest. The toughness plots with crack extension from the diagram resulted in a rising <i>R</i>-curve fitting into one smooth line, which showed a 1.4 MPa m<sup>1/2</sup> toughness increase during crack extension equivalent to one-grain diameter. The maximum bridging stress calculated from the <i>R</i>-curve, approximately 1.8 GPa, was also close to the previous results, while the stress was estimated to rise more steeply than previously thought.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20477","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fan Yang, Yun Fan, Maoyuan Li, Simiao Sha, Yuchen Liu, Yiran Li, Bin Liu
{"title":"Thermal properties and oxygen vacancy behaviors for corrosion products of lutetium silicates against CMAS","authors":"Fan Yang, Yun Fan, Maoyuan Li, Simiao Sha, Yuchen Liu, Yiran Li, Bin Liu","doi":"10.1111/jace.20507","DOIUrl":"https://doi.org/10.1111/jace.20507","url":null,"abstract":"<p>Rare earth silicates are promising thermal/environmental barrier coatings (T/EBC) materials facing silicon-based ceramic matrix composite substrates and have attracted much attention due to the severe CMAS (CaO–MgO–Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub>) corrosion. Understanding the mechanism of thermal conductivity and oxygen vacancy behavior of their CMAS corrosion products is crucial to evaluate the performance of coatings in post-service stage. In this work, thermal conductivity as well as the stability and migration behaviors of oxygen vacancy of these seven CMAS corrosion products are studied using first-principles calculations. Analysis of their phonon behaviors indicates that low-frequency phonons play an essential role in heat conduction due to their long phonon relaxation times. The predominant oxygen vacancy configurations for these seven products are determined and their temperature dependent concentrations are predicted according to the calculated formation energies. α-CaSiO<sub>3</sub> with low thermal conductivity and high migration energy barriers is suggested to be the potential corrosion product of T/EBC with excellent service performance. These discoveries do not only provide insights into the thermal conductivity and oxygen vacancy behavior of corrosion products, but also are expected to suggest their potential application as advanced T/EBC materials.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dendritic crystals of α-MoO3","authors":"Ying Yang, Makoto Nanko, Ngo Minh Chu, Thi Mai Dung Do, Tadachika Nakayama, Koichi Niihara, Hisayuki Suematsu","doi":"10.1111/jace.20515","DOIUrl":"https://doi.org/10.1111/jace.20515","url":null,"abstract":"<p>The dendritic structure possesses a remarkably large surface area, which is advantageous for numerous chemical reactions and physical processes. Currently, we are seeking an appropriate molybdenum trioxide target for the production of the radionuclide technetium-99 m (<sup>99m</sup>Tc) through neutron irradiation. In the present work, the synthesis of α-MoO<sub>3</sub> dendritic crystals was achieved by thermally evaporating α-MoO<sub>3</sub> powders in a tube furnace under a flowing argon gas atmosphere at evaporation temperatures (<i>T</i><sub>E</sub>) ranging from 800°C to 1000°C. The scanning electron microscope results demonstrated the successful synthesis of dendrites. The dendrites exhibited their maximum dimension at a temperature of 900°C. The dendrites were identified as α-MoO<sub>3</sub> through X-ray diffraction. α-MoO<sub>3</sub> dendrites originated from the elevated temperature region on the upper surface of the tube. The temperature distribution measurements indicate that the formation of dendrites occurred after the transition from non-uniform to uniform growth. To the best of our knowledge, this is the first report on synthesizing α-MoO<sub>3</sub> dendrites and investigating their growth mechanisms.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weiyi Ji, Yifan Zhou, Ziwei Chen, Jian-Xin Lu, Christopher Cheeseman, Chi-Sun Poon
{"title":"Improved foamed glass using carbonated recycled concrete powder as a foaming agent","authors":"Weiyi Ji, Yifan Zhou, Ziwei Chen, Jian-Xin Lu, Christopher Cheeseman, Chi-Sun Poon","doi":"10.1111/jace.20481","DOIUrl":"https://doi.org/10.1111/jace.20481","url":null,"abstract":"<p>A novel foaming agent derived from carbonated recycled concrete powder (CRCP) has been employed to produce foamed glass as an alternative to commercial CaCO<sub>3</sub>. Three sintering temperatures (750, 800, and 850°C) and five dosages (1%, 2%, 3%, 5%, and 9%) were conducted for two foaming agents (CRCP and CaCO<sub>3</sub>). The results demonstrated that the CRCP samples perform better than those produced with CaCO<sub>3</sub> as the foaming agent. This can be attributed to the more uniform pore structure observed through scanning electron microscopy and X-ray computed tomography analysis, and enhanced micro-mechanical strength determined by nanoindentation testing. The CRCP exhibited a moderate gas generation process, accompanied by the decomposition residues that facilitated enhanced crystalline formation within the matrix, ultimately resulting in improved performance. The findings unveiled the underlying mechanism behind the disparity in foaming properties between the two agents and highlighted the potential opportunities for waste material substitution in this industry.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Phase field study of ferroelastic domain switching behavior related to grain size in polycrystalline tetragonal zirconia","authors":"Chongyan Li, Junbao Li","doi":"10.1111/jace.20495","DOIUrl":"https://doi.org/10.1111/jace.20495","url":null,"abstract":"<p>t'-YSZ has received widespread attention in the application of thermal barrier coatings due to its ferroelasticity. Related studies have shown that the switching behavior of ferroelastic domains is influenced by grain size (GS), which in turn affects the final toughness of the material. This article constructs a phase field model to study the domain structure evolution and mechanical response of polycrystalline t'-YSZ under external loading. To describe the grain size effect of ferroelastic domain switching, grain boundary (GB) energy is introduced into the phase field model to measure the grain size effect of domain switching. By comparing the results of the uniaxial compression experiment with t'-YSZ, the reliability of our model was verified. The influence of grain size on the microstructure transformation and macroscopic mechanical behavior of ferroelastic domains was studied by considering two geometric models, complete and prefabricated cracks, while further considering the synergistic effect of grain size and grain orientation. The simulation results indicate a negative correlation between GS and coercive stress <span></span><math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>σ</mi>\u0000 <mi>c</mi>\u0000 </msub>\u0000 <annotation>${sigma _c}$</annotation>\u0000 </semantics></math>. The larger the GS, the higher the overall transformation degree of the ferroelastic domain. The switching of ferroelastic domains is related to grain orientation, and the smaller the grain size, the greater the angle at which the ferroelastic domains do not transform.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Long Yan, Xin Zhang, Shenlin Zhou, Qinglin Rong, Nan Liu, Wei Zhang, Jichao Li, Qingmei Lu
{"title":"Field emission tip effect and field emission performance of micro-tip arrays fabricated on single-crystal LaB6","authors":"Long Yan, Xin Zhang, Shenlin Zhou, Qinglin Rong, Nan Liu, Wei Zhang, Jichao Li, Qingmei Lu","doi":"10.1111/jace.20496","DOIUrl":"https://doi.org/10.1111/jace.20496","url":null,"abstract":"<p>A finite element simulation study is conducted using COMSOL Multiphysics software for tip effects such as induced potential, induced electric field intensity, and charge density of micro-tips in a micro-tips array under applied voltage. The simulation results indicate that under a constant micro-tip spacing <i>x</i>, the field shielding effect increases as the micro-tip curvature radius decreases. Moreover, when the tip spacing <i>x</i> is greater than twice the tip height <i>h</i>, the field shielding effect can be neglected. Based on the COMSOL simulation results of the micro-tips array, the femtosecond laser processing technology was employed to achieve controllable fabrication of micro-tips array microstructures on the (100) crystal plane of single-crystal LaB<sub>6</sub>. Under the condition of good geometric morphology of the tips, tips with a height of 10 µm and a minimum tip curvature radius of 0.2 µm could be processed, with good uniformity in array morphology and distribution. Field emission performance tests show that under testing conditions with a vacuum level of 1 × 10<sup>−5</sup> Pa and an applied electric field <i>E<sub>a</sub></i> of 5.6 V/µm, it exhibits a low turn-on electric field <i>E<sub>t</sub></i> (2.7 V/µm), a field emission current density of 4.36 A/cm<sup>2</sup>, and good emission stability.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Giovanna Jaques Caldeira, Andre Avancini Bernardes, Vitor L. Martins, José Fábian Schneider, Renato V. Gonçalves, Douglas Gouvêa
{"title":"Li ions segregated on anatase powders: Surface excess and ionic conductivity in the natural adsorbed water","authors":"Giovanna Jaques Caldeira, Andre Avancini Bernardes, Vitor L. Martins, José Fábian Schneider, Renato V. Gonçalves, Douglas Gouvêa","doi":"10.1111/jace.20499","DOIUrl":"https://doi.org/10.1111/jace.20499","url":null,"abstract":"<p>The exploration of doped titanium dioxide (TiO<sub>2</sub>) materials presents significant potential for advancing technologies in energy storage, catalysis, and electronics. Among various dopants, lithium (Li) ions have attracted considerable interest due to their role in lithium-ion batteries. However, the understanding of lithium-ion distribution within the bulk and at the interfaces (surface and grain boundaries) of anatase TiO<sub>2</sub> nanoparticles remains limited and poorly understood. The lithium concentrations examined in this study were 0.0, 0.7, 3.2, 6.5, and 16.7 mol%. The specific surface area increased notably for lithium concentrations above 3.2 mol%, indicating the segregation of lithium ions on the TiO<sub>2</sub> surface. This segregation was demonstrated using several techniques, including x-ray photoelectron spectroscopy, nuclear magnetic resonance (NMR), and diffuse reflectance infrared Fourier transform spectroscopy (FTIR-DRIFT). NMR, in particular, provided novel insights into the proportions of lithium segregated on the surface and at grain boundaries. Impedance spectroscopy measurements revealed that overall electrical conductivity increases proportionally with the excess of lithium ions on the surface, whereas it decreases in dry atmospheres. This suggests that the segregated lithium ions dissolve in the naturally adsorbed water layer on the nanoparticle surfaces, contributing to ionic conductivity. This study offers valuable insights into the effects of lithium distribution in the nanostructure of TiO<sub>2</sub>.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lan Long, Yuting Zhang, Henghai Zhu, Yujia Nie, Wei Zhou, Yang Li
{"title":"In situ growth of the Y3Si2C2 interphase in SiCf-reinforced mullite ceramics for enhanced electromagnetic wave absorption","authors":"Lan Long, Yuting Zhang, Henghai Zhu, Yujia Nie, Wei Zhou, Yang Li","doi":"10.1111/jace.20506","DOIUrl":"https://doi.org/10.1111/jace.20506","url":null,"abstract":"<p>To meet the rigorous demands placed on electromagnetic (EM) wave absorbing (EWA) materials by harsh service conditions and to reduce EM wave power density, the development of ceramic-based EWA materials with high reliability and stability has become a subject of significant focus. In this study, yttrium silicide carbide interphase was in situ synthesized on silicon carbide fibers to fabricate Y₃Si₂C₂–SiC<sub>f</sub> composite fibers by the molten salt method. These fibers were then incorporated into a mullite ceramic matrix, and Y₃Si₂C₂–SiC<sub>f</sub>/mullite composites were prepared by gel injection molding, aiming at enhancing the EWA properties. The Y₃Si₂C₂–SiC<sub>f</sub>/mullite composite exhibited a reflection loss of −28.97 dB at 2.44 mm thickness and an effective absorption bandwidth of 3.066 GHz, outperforming pure mullite and SiC<sub>f</sub>/mullite composites due to the addition of Y₃Si₂C₂–SiC<sub>f</sub>. A modified Drude–Lorentz model was developed to capture the multi-peak permittivity behavior of Y₃Si₂C₂–SiC<sub>f</sub>/mullite composites. The results showed that dipole relaxation and hopping migration of localized electrons played key roles in the overall microwave energy attenuation, which closely matched the experimental data. Furthermore, simulations of the electric field distribution and radar cross-section confirmed the superior energy loss capability and practical application potential of Y₃Si₂C₂–SiC<sub>f</sub>/mullite composites. This study offers valuable theoretical insights into the design and application of SiC<sub>f</sub>-reinforced ceramic-based EWA materials.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"SrAl2O4: Eu2+, Dy3+ mechanoluminescent phosphor for potential bearings stress distribution imaging","authors":"Guixian Xiong, Sheng Wu, Puxian Xiong, Haitao Lv, Weichao Huang, Jialong Huang, Xiaodong Pu","doi":"10.1111/jace.20494","DOIUrl":"https://doi.org/10.1111/jace.20494","url":null,"abstract":"<p>Mechanoluminescence (ML) materials have shown broad application potentials in stress sensing and structural monitoring due to in situ, real-time monitoring, and low trigger threshold. However, the accurate detection of stress distribution inside machinery still faces certain challenges. Based on a flexible ML film prepared by SrAl<sub>2</sub>O<sub>4</sub>: Eu<sup>2+</sup>, Dy<sup>3+</sup> phosphor and polydimethylsiloxane, this paper proposes a “stress difference” strategy to monitor the stress distribution inside the mechanical structure. By applying different loads and recording the linear relationship between ML intensity and the load, the local stress distribution in the engine bearing can be measured. By comparing the difference between I<sub>ML</sub> and I<sub>PersL</sub>, the specific stress distribution inside the machine is successfully inferred. This study provides new ideas for the application of ML materials in stress sensing, which may open up an innovative method for stress monitoring inside mechanical structures.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20494","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Amir Jamilludin, Koichiro Hayashi, Yusril Yusuf, Kunio Ishikawa
{"title":"Low-crystalline magnesium-doped carbonate apatite/β-tricalcium phosphate granules from sea urchin spine","authors":"Muhammad Amir Jamilludin, Koichiro Hayashi, Yusril Yusuf, Kunio Ishikawa","doi":"10.1111/jace.20498","DOIUrl":"https://doi.org/10.1111/jace.20498","url":null,"abstract":"<p>The development of synthetic granules with performances equivalent to those of autogenous bone grafts is critical for effective bone replacement. Herein, we report on the fabrication of low-crystalline Mg-doped biphasic carbonate apatite/β-tricalcium phosphate (Mg-CAp/β-TCP) granules, with cylindrical shapes, concave surfaces, and multiscale pores, from sea urchin spines. The β-TCP/CAp ratios and Mg contents in the Mg-CAp/β-TCP granules were controlled to remain within 0.46–0.87 and 6.03–9.32 mol%, respectively. The Mg-CAp/β-TCP granules preserved the multiscale pores and concave surfaces of the sea urchin spines. The Mg-CAp/β-TCP granules exhibited inner stereom micropores (3–25 µm), thickened stereom micropores (<14 µm), interseptal gaps (20–43 µm), and concavities (26–41 µm), along with micropores (<3 µm) and nanopores (<100 nm) corresponding to intercrystal spaces. The rounded and uniformly shaped Mg-CAp/β-TCP granules facilitated denser packing in a simulated defect mold. The Mg-CAp/β-TCP granules exhibited compressive and diametral tensile strengths of 1.12–1.51 and 0.17–0.21 MPa, respectively. The distinctive physicochemical and structural characteristics of the Mg-CAp/β-TCP granules can be anticipated to facilitate controlled resorption rates and promote osteogenesis and angiogenesis, facilitating rapid bone defect repair. Furthermore, the adequate mechanical features of the Mg-CAp/β-TCP granules enable ease of handling during bone defect filling and potential application in load-bearing sites.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}