Journal of Alloys and Compounds最新文献

{"title":"Nanotopographical Design and Corrosion Resistance Improvement of Ti40Zr10Cu36Pd14 Glassy Alloy Using Alkaline Chemical Treatment","authors":"Kirti Tiwari, Yohan Douest, Paula Milena Giraldo-Osorno, Jules Galipaud, Thierry Douillard, Nicholas Blanchard, Anders Palmquist, Nicolas Courtois, Damien Fabrègue, Jérôme Chevalier, Paola Rizzi, Benoit Ter-Ovanessian","doi":"10.1016/j.jallcom.2025.180150","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180150","url":null,"abstract":"Ti-based bulk metallic glasses (Ti-BMGs) are promising candidates for mini-invasive dental implant devices due to their unique properties. Among them, Ti₄₀Zr₁₀Cu₃₆Pd₁₄ has received particular attention in the literature for its potential biocompatibility. However, its high copper content limits corrosion resistance by promoting localised corrosion (pitting or crevice). This study presents a rapid and straightforward surface modification technique known as chemical pseudo-dealloying to reduce copper content in the top surface layer, enriching palladium and enhancing corrosion resistance limiting pitting occurrence. Additionally, the selective etching of Cu creates nanoscale surface features that could be interesting for cell adhesion and differentiation. The Pd-rich nanoporous layer was thoroughly characterized by its topography, chemical composition, electrochemical behaviour, and biocompatibility. These findings pave the way for tailoring the topography and surface properties of metallic amorphous alloys for biomedical applications.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"90 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143782786","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}

{"title":"The influence of heating temperature on magnetization reversal process of SrCoO3−δ epitaxial thin film mediated through ionic liquid−gated technology","authors":"J. Zhang, L.F. Wang, J.C. Ma, T.C Su","doi":"10.1016/j.jallcom.2025.180240","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180240","url":null,"abstract":"The utilization of ionic liquid gating (ILG) as a gate dielectric to modulate the oxygen (O<sup>2−</sup>) ions of transition metal oxides and thereby control their various properties, holding potential applications in the area of electronics and energy storage. However, numerous experiments have indicated the challenge of fast and reversibly extracting or inserting O<sup>2−</sup> ions across the entire oxide structure at room temperature (RT). Here, the impact of ILG manipulation on magnetic properties in perovskite SrCoO<sub>3−δ</sub> (PV−SCO, 0 < δ < 0.25) epitaxial thin films is explored by varying the heating temperatures. The findings demonstrate that due to the difficulty of inserting O<sup>2−</sup> ions completely into the entire sample following manipulation with 0<!-- --> <!-- -->V<span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mover is=\"true\"><mo is=\"true\">→</mo><mrow is=\"true\"><mn is=\"true\">30</mn><mi is=\"true\">min</mi></mrow></mover></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"3.471ex\" role=\"img\" style=\"vertical-align: -0.028ex; margin-bottom: -0.323ex;\" viewbox=\"0 -1343.3 2110.3 1494.4\" width=\"4.901ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><g is=\"true\"><use x=\"-85\" xlink:href=\"#MJMAIN-2212\" y=\"0\"></use><g transform=\"translate(341.3830253947031,0) scale(1.40375117876091,1)\"><use xlink:href=\"#MJMAIN-2212\"></use></g><use x=\"1109\" xlink:href=\"#MJMAIN-2192\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(28,712)\"><g is=\"true\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-33\"></use><use transform=\"scale(0.707)\" x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(874,0)\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-6D\"></use><use transform=\"scale(0.707)\" x=\"833\" xlink:href=\"#MJMAIN-69\" y=\"0\"></use><use transform=\"scale(0.707)\" x=\"1112\" xlink:href=\"#MJMAIN-6E\" y=\"0\"></use></g></g></g></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mover is=\"true\"><mo is=\"true\">→</mo><mrow is=\"true\"><mn is=\"true\">30</mn><mi is=\"true\">min</mi></mrow></mover></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mover is=\"true\"><mo is=\"true\">→</mo><mrow is=\"true\"><mn is=\"true\">30</mn><mi is=\"true\">min</mi></mrow></mover></mrow></math></script></span>+4<!-- --> <!-- -->V<span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mover is=\"true\"><mo is=\"true\">→</mo><mrow is=\"true\"><mn is=\"true\">30</mn><mi is=\"true\">min</mi","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"80 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775713","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}

{"title":"Controllable synthesis of nano-CeO2 by the hydrothermal route and its effect on the activity of CO2 non-reductive transformation","authors":"Yuying Yang, Junjie Ma, Na Liu, Xueli Huang, Lijun Jin, He Huang","doi":"10.1016/j.jallcom.2025.180232","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180232","url":null,"abstract":"The catalytic conversion of CO₂ and diols to polycarbonates is conducive to the construction of a sustainable carbon source, but its efficiency largely depends on the catalysts. In this study, CeO₂ catalysts with different sizes and morphologies were synthesized via hydrothermal methods. The effect of CeO₂ morphology (nanoparticles, nanorods, and nanocubes) on this reaction was further investigated. Precise control of nano-CeO₂ morphology altered the surface Ce⁴⁺/Ce³⁺ ratio, inducing surface defects and enhancing catalytic activity. Among the tested morphologies, CeO₂ nanorods exhibited the highest catalytic performance (diol conversion > 90.5%, polycarbonate selectivity > 89.3%) and stability. The exposed (110) and (100) planes of CeO₂ increased oxygen vacancy concentrations and strengthened CO₂ interactions, promoting bicarbonate and bidentate carbonate formation on the CeO₂ surface and thereby enhancing CO₂ non-reductive transformation activity.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"26 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775793","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}

{"title":"Eu3+-Doped Fluorite-Type Molybdate Phosphors for Narrow-Band Red Emission with High Efficiency","authors":"Suyin Zhang,&nbsp;Qinhua Wei,&nbsp;Hang Yin,&nbsp;Gao Tang,&nbsp;Laishun Qin","doi":"10.1016/j.jallcom.2025.180172","DOIUrl":"10.1016/j.jallcom.2025.180172","url":null,"abstract":"<div><div>Eu³⁺ is regarded as the most important red luminescent activator among rare earth ions. In this work, Eu³⁺-activated Gd₄MgMo₃O₁₆ nanophosphors were synthesized using the sol-gel method. The fluorite-type cubic structure of the material was unequivocally confirmed by XRD patterns and Rietveld structure refinements. A comprehensive investigation was conducted on the band width, intrinsic luminescence, and decay lifetime of the host material. The detailed luminescence transitions of Eu³⁺ activators in the Gd₄MgMo₃O₁₆ host are reported. The phosphor exhibited an extremely narrow luminescence line at 616<!--> <!-->nm (corresponding to the ⁵D₀ → ⁷F₂ transition in Eu³⁺) with a full width at half maximum (FWHM) of approximately 1<!--> <!-->nm. Its CIE chromaticity coordinates closely matched the NTSC standard for ideal red light. Based on the luminescence efficiency, the optimal Eu³⁺ doping concentration in the host is 40<!--> <!-->mol%. The phosphor's excitation spectrum aligned well with the output emission wavelengths of commercial near-UV and blue LED semiconductor chips. Specifically, Gd_{4-4<em>x</em>}Eu_4<em>x</em>MgMo₃O₁₆ (<em>x</em> = 0.4) has a maximum quantum efficiency (QE) of 70.5%, and exhibits high thermal ability, with an activation energy value of 0.437<!--> <!-->eV. These characteristics render it particularly suitable for red-emitting applications in near-ultraviolet/blue GaN LED technologies.</div></div>","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"1024 ","pages":"Article 180172"},"PeriodicalIF":5.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775788","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}

{"title":"Ultrafine grain stabilization and corrosion studies on supersonic cold-sprayed Al-5Si/Al2O3 coating via thermal annealing","authors":"Nasir Ullah, Naeem Ul Haq Tariq, Madhusudan Dhakal, Xinyu Cui, Jiqiang Wang, Tianying Xiong","doi":"10.1016/j.jallcom.2025.180129","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180129","url":null,"abstract":"In order to enhance the corrosion protection of magnesium alloys, a novel eutectic Al-5Si/Al₂O₃ composite coating was applied to an AZ31 substrate by supersonic cold-spray technique, followed by annealing at 400 °C. The as sprayed and thermally treated coatings were subjected to systematic characterization for microstructural, mechanical and corrosion analyses. The results demonstrated that thermal input led to pronounced increase in the fraction of low-angle grain boundaries (LAGB), from 54% to 70%, while the average grain size value remained in the ultrafine regime (&lt;1<!-- --> <!-- -->µm). Although the thermal treatment rendered hardness and porosity slightly changed, a substantial enhancement in corrosion resistance was observed, with the protection efficiency increasing from 40% to 53% and corrosion current density (<em>I</em>_{<em>corr</em>}) decreasing by one order of magnitude. This significant improvement in corrosion resistance primarily originated from substantial increase in LAGB length fraction, decrease in grain boundary energy, as revealed by electron backscatter diffraction (EBSD), a reduction in porosity due to annealing, and the formation of Al₂O₃, Al(OH)₃, SiO₂, Al₂SiO₅, and albite on the surface, as confirmed by X-ray diffraction (XRD). These findings underscore the influence of annealing in optimizing both the microstructural features and corrosion resistance properties of Al-5Si/Al₂O₃ composite coating.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"183 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775803","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}

{"title":"Hot deformation behavior and microstructure evolution of a novel as-forged Ni-based superalloy","authors":"Xiaobin Song, Zhengxin Tang, Xikou He, Lei Jia, Gen Li, Jinshan He, Xitao Wang","doi":"10.1016/j.jallcom.2025.180195","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180195","url":null,"abstract":"The high-temperature mechanical properties of the nickel-based superalloy are exceptionally remarkable. However, the high level of alloying and limited hot working window of the alloy trigger significant challenges to its processing and production. The microstructural evolution and thermal deformation characteristics of the novel forged nickel-based superalloy were investigated through isothermal compression tests conducted at temperatures ranging from 1000 to 1200 ℃, strain rates varying from 0.001 to 1<!-- --> <!-- -->s⁻¹, and true strains reaching up to 0.693. The results indicate that the novel Ni-based alloy is a material with negative temperature sensitivity and positive rate sensitivity. The stress-strain curves in question encompass the phenomena of dynamic recovery (DRV) and dynamic recrystallization (DRX). The hot working maps of the alloy were constructed based on the dynamic materials model (DMM). It revealed the existence of two unstable regions: one located in the low-temperature and high-strain-rate area, and the other in the high-temperature and high-strain-rate area. The optimal parameters for isothermal deformation, combined with the hot working maps and the microstructure, were found to be 1100-1180 ℃/0.03-0.36<!-- --> <!-- -->s⁻¹. The phenomena of discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) were observed during the experiment. With respect to the exceptional case of 1<!-- --> <!-- -->s^-1, the <span><span style=\"\"></span><span data-mathml='&lt;math xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mi is=\"true\"&gt;&amp;#x3B7;&lt;/mi&gt;&lt;/math&gt;' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"1.855ex\" role=\"img\" style=\"vertical-align: -0.697ex;\" viewbox=\"0 -498.8 503.5 798.9\" width=\"1.169ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use xlink:href=\"#MJMATHI-3B7\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi is=\"true\">η</mi></math></span></span><script type=\"math/mml\"><math><mi is=\"true\">η</mi></math></script></span> revealed gradual decrease as the temperature dropped. As a result, the dominant deformation mechanism of the alloy changed from DDRX to a hybrid of DDRX and CDRX, then to DDRX + CDRX + DRV, and ultimately to the concurrent presence of CDRX and DRV.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"73 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775797","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}

{"title":"Ultra-strong yet ductile Ni49Fe20Al17V6Co4Cr4 eutectic high-entropy alloys with duplex heterogeneous structure","authors":"Xiangkui Liu, Chenglong Zhou, Jingying Liu, Qianye Wang, Xuecong Zhang, Weixia Dong, Xiaoxi Wang, Xulong An, Wei Wei, Dandan Wang, Zhenfei Jiang","doi":"10.1016/j.jallcom.2025.180219","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180219","url":null,"abstract":"Achieving an ultrahigh strength and ductility in high-entropy alloys (HEAs) is a huge challenge for traditional HEAs due to some unavoidable casting defects and component segregation. Here, a series of Ni₄₉Fe₂₀Al₁₇V₆Co₄Cr₄ eutectic high-entropy alloys (EHEAs) with heterogeneous structure were architected through thermomechanical processing. In particular, the cold-rolled Ni₄₉Fe₂₀Al₁₇V₆Co₄Cr₄ EHEA followed by annealing at 750 °C for 2<!-- --> <!-- -->hours shows an excellent combination of ultrahigh strength and ductility, i.e., an ultrahigh yield strength of ~1622<!-- --> <!-- -->MPa, an ultrahigh tensile strength of ~1820 MPa, as well as remained total elongation of 10.4%. Such ultrahigh strength is mainly attributed to HDI hardening caused by the deformation incompatibility between the soft recrystallized grains and the hard non-recrystallized grains, as well as the precipitation strengthening caused by the FCC/L1₂ phase. Our study provides a promising avenue for future exploration of high-performance materials by constructing a dual-phase heterogeneous microstructure.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"37 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775801","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}

{"title":"Formation of porous lithium silicate glass-ceramics with high flexural strength via cold sintering process associated with post-annealing technique","authors":"Xigeng Lyu, Xinyi Bai, Ding Li, Yeongjun Seo, Tohru Sekino, Yaming Zhang, Fu Wang","doi":"10.1016/j.jallcom.2025.180209","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180209","url":null,"abstract":"Using 20<!-- --> <!-- -->M NaOH solution and raw glass-ceramic powders with varied crystallinities, porous lithium silicate (Li₂SiO₃, LM or Li₂Si₂O₅, LD) glass-ceramics with high flexural strength were prepared via cold sintering process (CSP) associated with post-annealing technique. With the crystallinities of raw powders rising, less Si–OH groups formed for cold sintered samples, and reducing H₂O vapor formed as foaming agent for preparing porous glass-ceramics. Correspondingly, total porosities and mean pore sizes decreased from 58.5 ± 1.6% to 11.7 ± 1.4% and from 52.47 ± 52.02<!-- --> <!-- -->μm to 11.76 ± 5.96<!-- --> <!-- -->μm for porous ones. Their appearances varied from gray to white, and the edges of some were even blue owing to the unexpected side reactions. Only LM crystals precipitated within pore walls of porous ones, for which volume fractions and aspect ratios rose from 73.91 vol.% to 87.66 vol.% and from 6.23 to 7.27 when the crystallinities of raw powders were below 90.14%. Whereas, 81.68 vol.% LD, 8.97 vol.% LM and 1.98 vol.% quartz crystals existed in pore walls with the use of raw powders possessing crystallinities of 90.14%, and aspect ratio of major LD crystal was 2.90. Flexural strengths of the resultant porous lithium silicate glass-ceramics rose from 256.9 ± 13.9<!-- --> <!-- -->MPa to 345.3 ± 18.0<!-- --> <!-- -->MPa, which exhibited great potential in preparing polymer-infiltrated-ceramic-network (PICN) materials for dental restoration applications, and further researches were required relating to tailoring porosities.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"34 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143775857","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}

{"title":"In-situ monitoring the structural pathway of a Ti-based alloy from metallic liquid to metallic glass","authors":"K Georgarakis, ME Stiehler, L Hennet, Y Guo, J Antonowicz, DV Louzguine-Luzgin, MR Jolly, J Andrieux, G Vaughan, AL Greer","doi":"10.1016/j.jallcom.2025.180214","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180214","url":null,"abstract":"A metallic glass is formed when a molten metallic alloy is cooled rapidly enough that crystallisation is avoided. However, the way the atomic structure of the liquid converts to that of the glass is generally unknown. The main challenge is the sufficiently fast experimental acquisition of structural data in the undercooled liquid regime necessitated by the high cooling rates needed to avoid crystallisation. In the present study, using aerodynamic levitation, the Ni-free Ti-based alloy Ti₄₀Zr₁₀Cu₃₄Pd₁₄Sn₂ was vitrified in-situ in a high-energy synchrotron X-ray beam while diffraction data were acquired during cooling from above the liquidus temperature <em>T</em>_liq to well below the glass-transition temperature <em>T</em>_g. The structure in the undercooled liquid regime shows an accelerated evolution. Both the local order in the short (SRO) and medium range (MRO) increases rapidly as the undercooled liquid approaches <em>T</em>_g, below which the amorphous structure “freezes”. Nevertheless, distinct differences between the evolution of SRO and MRO were observed. The structural rearrangements in the undercooled liquid are found to be correlated with a rapid increase in viscosity of the metallic liquid upon cooling. The new findings shed light on the evolution of the atomic structure of metallic liquids during vitrification and the structural origins of the sluggish kinetics that suppress nucleation and growth of crystalline phases.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"58 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766495","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}

{"title":"High thermoelectric performance in donor-substituted strontium titanate-based composites processed by laser floating zone","authors":"Diogo Lopes, Miguel A. Vieira, Nuno M. Ferreira, Vladimir V. Shvartsman, Oscar J. Dura, Francisco Q. Batista, Andrei N. Salak, Sergey Mikhalev, Florinda Costa, Andrei V. Kovalevsky","doi":"10.1016/j.jallcom.2025.180106","DOIUrl":"https://doi.org/10.1016/j.jallcom.2025.180106","url":null,"abstract":"Oxide thermoelectrics, made from abundant, eco-friendly materials, can withstand high-temperature gradients, making them highly promising for high-temperature waste heat harvesting. Recent advancements in the efficiency of thermoelectric material families have been driven by composite approaches, fostering synergistic effects between materials, further enhanced by advanced processing techniques. Accordingly, this study explores the design of oxide-based thermoelectric composites, involving the redistribution of a common substituting cation between composite phases, driven by laser floating zone (LFZ) processing. Niobium substituted strontium titanate/rutile composite material with a nominal composition Sr_0.97Ti_0.8Nb_0.2O₃ / 0.15Ti_0.95Nb_0.05O₂ was processed by LFZ at various pulling rates (50, 100, and 200<!-- --> <!-- -->mm/h), followed by post-thermal treatment under highly reducing conditions. The obtained samples showed inhomogeneous niobium distribution between perovskite and rutile phases shaped by strongly non-equilibrium conditions inherent to the LFZ processing, in contrast to the conventional solid-state route. Adjusting the pulling rate enabled a certain degree of control over niobium incorporation into both phases. Primarily driven by an enhanced Seebeck coefficient, the LFZ-processed and thermally treated samples demonstrated high power factors, reaching 1350-820 μW·K^-2·m^-1 at 473-1173<!-- --> <!-- -->K, respectively. An appealing ZT of 0.52 at 1173<!-- --> <!-- -->K was achieved for the composite sample processed at 100<!-- --> <!-- -->mm/h and subjected to thermal treatment. This performance is attributed to a combination of a high power factor and low thermal conductivity (~2<!-- --> <!-- -->W·m^-1·K^-1 at 1173<!-- --> <!-- -->K), enabled by phase and compositional inhomogeneities, as well as residual porosity introduced by LFZ processing. The LFZ technique offers considerable potential for optimisation and has proven to be a powerful tool for designing ceramic composite thermoelectric materials.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"25 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766502","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}