Pub Date : 2026-08-01Epub Date: 2026-02-11DOI: 10.1016/j.jeurceramsoc.2026.118230
Hao Chen , Hong Liu , Jie Yin , Voon-Kean Wong , David Boon Kiang Lim , Chao Jiang , Jie Xing , Kui Yao , Jianguo Zhu
Pb(Mg1/3Nb2/3)O3-Pb(Zr0.41Ti0.59)O3 is a perovskite material system with superior piezoelectric properties. Here, with optimized Nd ions introduced as soft dopants into the A-site of the lattice, the piezoelectric constant (d33) was significantly enhanced from 318 pC/N to 825 pC/N. Microstructural characterization and electrical property measurements revealed that the outstanding piezoelectric performance primarily originated from the formation of polar nanoregions (PNRs) induced by the synergistic regulation of phase structure and relaxor characteristics. The presence of PNRs was further confirmed by the observation of Moiré fringes using transmission electron microscopy. The activation energy analysis indicated that Nd-doped PNRs significantly facilitate domain switching, thereby improving piezoelectric properties. As a demonstration of the practical value of the improved piezoelectric properties, the PMNZT-xNd ceramic exhibits enhanced ultrasonic structural health monitoring performance, identifying defects to a depth of 0.06 mm in ultrasonic detection experiments.
{"title":"Enhancing piezoelectric properties of PZT-based ceramics for ultrasonic device application via Nd-doping and modulating polar nanoregions","authors":"Hao Chen , Hong Liu , Jie Yin , Voon-Kean Wong , David Boon Kiang Lim , Chao Jiang , Jie Xing , Kui Yao , Jianguo Zhu","doi":"10.1016/j.jeurceramsoc.2026.118230","DOIUrl":"10.1016/j.jeurceramsoc.2026.118230","url":null,"abstract":"<div><div>Pb(Mg1/3Nb2/3)O<sub>3</sub>-Pb(Zr<sub>0.41</sub>Ti<sub>0.59</sub>)O<sub>3</sub> is a perovskite material system with superior piezoelectric properties. Here, with optimized Nd ions introduced as soft dopants into the A-site of the lattice, the piezoelectric constant (<em>d</em><sub>33</sub>) was significantly enhanced from 318 pC/N to 825 pC/N. Microstructural characterization and electrical property measurements revealed that the outstanding piezoelectric performance primarily originated from the formation of polar nanoregions (PNRs) induced by the synergistic regulation of phase structure and relaxor characteristics. The presence of PNRs was further confirmed by the observation of Moiré fringes using transmission electron microscopy. The activation energy analysis indicated that Nd-doped PNRs significantly facilitate domain switching, thereby improving piezoelectric properties. As a demonstration of the practical value of the improved piezoelectric properties, the PMNZT-<em>x</em>Nd ceramic exhibits enhanced ultrasonic structural health monitoring performance, identifying defects to a depth of 0.06 mm in ultrasonic detection experiments.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 9","pages":"Article 118230"},"PeriodicalIF":6.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191586","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}
In this work, the influence of aliovalent doping with Al3 + and Ta5+ cations on the structure and thermal properties of La2Zr2O7 (LZO) was investigated and the solubility of Al3+ and Ta5+ in LZO separately and jointly was studied for the first time. The samples were synthesized by mechanochemical activation followed by sintering at 1200 °C and 1500 °C. It was established that doping maintains the pyrochlore-type structure (space group Fdm) within observed solubility limits (Al3+ up to x ≈ 0.12 and Ta5+ up to y ≈ 0.48). While the CTE of pure LZO increases with temperature (from 7.97 at 25°C to 11.50 ×10⁻⁶ °C⁻¹ at 1300°C), co-doping with Al3+ and Ta5+, specifically for the La1.96Al0.09Ta0.25Zr1.7O7.075 composition, resulted in a remarkably stable CTE (from 9.09 at 25°C to 9.82 ×10⁻⁶ °C⁻¹ at 1300°C) over a wide temperature range, a critical factor for thermal barrier coatings.
{"title":"Aliovalent doping of La2Zr2O7 with Al³ ⁺ and Ta⁵⁺ for CTE tuning","authors":"A.B. Kuznetsov , S.F. Solodovnikov , D. Sagatova , A.O. Klimov , P.A. Abramov , K.A. Kokh","doi":"10.1016/j.jeurceramsoc.2026.118215","DOIUrl":"10.1016/j.jeurceramsoc.2026.118215","url":null,"abstract":"<div><div>In this work, the influence of aliovalent doping with Al<sup>3 +</sup> and Ta<sup>5+</sup> cations on the structure and thermal properties of La<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> (LZO) was investigated and the solubility of Al<sup>3+</sup> and Ta<sup>5+</sup> in LZO separately and jointly was studied for the first time. The samples were synthesized by mechanochemical activation followed by sintering at 1200 °C and 1500 °C. It was established that doping maintains the pyrochlore-type structure (space group <em>Fd</em> <span><math><mover><mn>3</mn><mo>¯</mo></mover></math></span><em>m</em>) within observed solubility limits (Al<sup>3+</sup> up to <em>x</em> ≈ 0.12 and Ta<sup>5+</sup> up to <em>y</em> ≈ 0.48). While the CTE of pure LZO increases with temperature (from 7.97 at 25°C to 11.50 ×10⁻⁶ °C⁻¹ at 1300°C), co-doping with Al<sup>3+</sup> and Ta<sup>5+</sup>, specifically for the La<sub>1.96</sub>Al<sub>0.09</sub>Ta<sub>0.25</sub>Zr<sub>1.7</sub>O<sub>7.075</sub> composition, resulted in a remarkably stable CTE (from 9.09 at 25°C to 9.82 ×10⁻⁶ °C⁻¹ at 1300°C) over a wide temperature range, a critical factor for thermal barrier coatings.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 9","pages":"Article 118215"},"PeriodicalIF":6.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191686","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}
In recent times, dispersion strengthening has been given prime importance by researchers to modify the microstructure and enhance the mechanical properties of tungsten alloys for their applications in strategic sectors. The present study focuses on the incorporation of Y2O3, ZrB2, and graphene nanoplatelet (GNP) in W-0.7Ni-0.3Fe alloys to improve their overall characteristics. To achieve the same, the selected alloy compositions were blended, compacted, and then sintered at 1500 °C for 75 min in H2 atmosphere. It was observed that the addition of nano Y2O3 and GNP increases the sintered density of the WHAs. FESEM and EPMA analysis exhibit the uniform distribution of dispersoids in WHAs. It was noticed that the maximum compressive strength of 1985.6 MPa was obtained in 1 wt% Y2O3 incorporated W-0.7Ni-0.3Fe alloy, followed by Y2O3 + GNP, base alloy, GNP, and ZrB2 incorporated alloys. The maximum bulk hardness of ∼347 HV was obtained in the Y2O3 + GNP incorporated WHAs. Overall, the combined incorporation of Y2O3 and GNP was effective in improving the densification, microstructure and mechanical properties of sintered W-based systems.
{"title":"The effect of ZrB2, Y2O3, and/or graphene nanoplatelet incorporation on densification, microstructural evolution, and compressive deformation of W-0.7Ni-0.3Fe alloys","authors":"Deepak Adhikari , Suvam Sarthak Tripathy , Suresh Chandra Adhikari , Ashirbad Nayak , Alok Kumar Prusty , Tapas Kumar Sahoo , Mayadhar Debata , Pradyut Sengupta","doi":"10.1016/j.ijrmhm.2026.107694","DOIUrl":"10.1016/j.ijrmhm.2026.107694","url":null,"abstract":"<div><div>In recent times, dispersion strengthening has been given prime importance by researchers to modify the microstructure and enhance the mechanical properties of tungsten alloys for their applications in strategic sectors. The present study focuses on the incorporation of Y<sub>2</sub>O<sub>3</sub>, ZrB<sub>2</sub>, and graphene nanoplatelet (GNP) in W-0.7Ni-0.3Fe alloys to improve their overall characteristics. To achieve the same, the selected alloy compositions were blended, compacted, and then sintered at 1500 °C for 75 min in H<sub>2</sub> atmosphere. It was observed that the addition of nano Y<sub>2</sub>O<sub>3</sub> and GNP increases the sintered density of the WHAs. FESEM and EPMA analysis exhibit the uniform distribution of dispersoids in WHAs. It was noticed that the maximum compressive strength of 1985.6 MPa was obtained in 1 wt% Y<sub>2</sub>O<sub>3</sub> incorporated W-0.7Ni-0.3Fe alloy, followed by Y<sub>2</sub>O<sub>3</sub> + GNP, base alloy, GNP, and ZrB<sub>2</sub> incorporated alloys. The maximum bulk hardness of ∼347 HV was obtained in the Y<sub>2</sub>O<sub>3</sub> + GNP incorporated WHAs. Overall, the combined incorporation of Y<sub>2</sub>O<sub>3</sub> and GNP was effective in improving the densification, microstructure and mechanical properties of sintered W-based systems.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107694"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146032954","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 : 2026-08-01Epub Date: 2026-02-02DOI: 10.1016/j.jeurceramsoc.2026.118204
Siyuan Wang , Wei Cai , WenJin Wu , Huasong Liu , Jianwei Zheng , Liang Qiao , Yao Ying , Juan Li , Jing Yu , Naoki Wakiya , Jingwu Zheng , Shenglei Che
Cold sintering, characterized by low temperature, low energy consumption, and environmental friendliness, offers a promising route for sintering SrFe12O19. This study systematically investigates the effects of transient solvent composition, sintering temperature, and powder morphology on the densification mechanism of SrFe12O19. In the acetic acid–ethanol transient solvent system, Fe3 + ions preferentially dissolved and reacted with acetate and hydroxyl groups to form iron–carboxylate species, which facilitated particle bonding and densification. However, increased solvent concentration and cold sintering temperature cause its decomposition into Fe2O3, and gas release; trapped gas forms pores that impede densification, leading to reduced densification at higher temperatures. Meanwhile, irregular powders promote the “dissolution–precipitation” process more effectively than spherical ones. Under optimized conditions, 16 mol/L transient solvent concentration, 40 wt% addition, 250 °C sintering temperature, 1 GPa pressure, and 3 h holding time, the ball-milled powder achieved a optimal combined magnetic properties (Hcj = 5.31 kOe, Ms = 60.39 emu/g).
{"title":"Mechanistic elucidation of cold sintering behavior in SrFe12O19 ceramics: Role of transient solvent, temperature, and particle morphology","authors":"Siyuan Wang , Wei Cai , WenJin Wu , Huasong Liu , Jianwei Zheng , Liang Qiao , Yao Ying , Juan Li , Jing Yu , Naoki Wakiya , Jingwu Zheng , Shenglei Che","doi":"10.1016/j.jeurceramsoc.2026.118204","DOIUrl":"10.1016/j.jeurceramsoc.2026.118204","url":null,"abstract":"<div><div>Cold sintering, characterized by low temperature, low energy consumption, and environmental friendliness, offers a promising route for sintering SrFe<sub>12</sub>O<sub>19</sub>. This study systematically investigates the effects of transient solvent composition, sintering temperature, and powder morphology on the densification mechanism of SrFe<sub>12</sub>O<sub>19</sub>. In the acetic acid–ethanol transient solvent system, Fe<sup>3 +</sup> ions preferentially dissolved and reacted with acetate and hydroxyl groups to form iron–carboxylate species, which facilitated particle bonding and densification. However, increased solvent concentration and cold sintering temperature cause its decomposition into Fe<sub>2</sub>O<sub>3</sub>, and gas release; trapped gas forms pores that impede densification, leading to reduced densification at higher temperatures. Meanwhile, irregular powders promote the “dissolution–precipitation” process more effectively than spherical ones. Under optimized conditions, 16 mol/L transient solvent concentration, 40 wt% addition, 250 °C sintering temperature, 1 GPa pressure, and 3 h holding time, the ball-milled powder achieved a optimal combined magnetic properties (<em>H</em><sub><em>cj</em></sub> = 5.31 kOe, <em>M</em><sub><em>s</em></sub> = 60.39 emu/g).</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 9","pages":"Article 118204"},"PeriodicalIF":6.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098721","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}
Shape memory materials (SMMs) enable strain recovery after deformation. Ferroelectric ceramics, such as BaTiO3 (BTO), can also demonstrate the shape memory effect (SME) through a ferroelectric-paraelectric transformation. While grain size (GS) is known to significantly influence SME in shape memory alloys (SMAs), its role in shape memory ceramics (SMCs) remains unexplored. In this work, BTO ceramics with GS ranging from 49 μm to 0.54 μm were prepared via a two-step sintering method to investigate the GS effect on SME. Results reveal that decreasing GS significantly enhances the residual strain, with the maximum residual strain increasing by approximately 3 times from 0.05 % (coarse grains, 49 μm) to 0.15 % (fine grains, 0.54 μm). This improvement is attributed to the increased number of 90° domains in smaller GS BTO ceramics. Additionally, external stress applied during cooling leads to a linear increase in residual strain. This phenomenon is explained from an energy perspective. Stress raises the system's strain energy, which encourages the formation of more 90° domains and fewer 180° domains as BTO transitions to the tetragonal phase. This work provides critical insights into enhancing SME in ferroelectric ceramics by controlling GS and domain structure, offering a potential strategy to tailor SME in SMCs.
{"title":"Grain size effect on the shape memory effect of BaTiO3","authors":"Xiongxin Guo, Baoju Xia, Xinnan Shi, Xinrong Yang, Yagang Qi, Baojin Chu","doi":"10.1016/j.jeurceramsoc.2026.118229","DOIUrl":"10.1016/j.jeurceramsoc.2026.118229","url":null,"abstract":"<div><div>Shape memory materials (SMMs) enable strain recovery after deformation. Ferroelectric ceramics, such as BaTiO<sub>3</sub> (BTO), can also demonstrate the shape memory effect (SME) through a ferroelectric-paraelectric transformation. While grain size (GS) is known to significantly influence SME in shape memory alloys (SMAs), its role in shape memory ceramics (SMCs) remains unexplored. In this work, BTO ceramics with GS ranging from 49 μm to 0.54 μm were prepared via a two-step sintering method to investigate the GS effect on SME. Results reveal that decreasing GS significantly enhances the residual strain, with the maximum residual strain increasing by approximately 3 times from 0.05 % (coarse grains, 49 μm) to 0.15 % (fine grains, 0.54 μm). This improvement is attributed to the increased number of 90° domains in smaller GS BTO ceramics. Additionally, external stress applied during cooling leads to a linear increase in residual strain. This phenomenon is explained from an energy perspective. Stress raises the system's strain energy, which encourages the formation of more 90° domains and fewer 180° domains as BTO transitions to the tetragonal phase. This work provides critical insights into enhancing SME in ferroelectric ceramics by controlling GS and domain structure, offering a potential strategy to tailor SME in SMCs.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 9","pages":"Article 118229"},"PeriodicalIF":6.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191588","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 : 2026-08-01Epub Date: 2026-02-06DOI: 10.1016/j.jeurceramsoc.2026.118218
Lu Sun , Ziyang Ma , Zhenfei Cai , Kai Li , Yuxin Lin , Qinyu Wu , Yanan Chen , Shimiao Chen , Junzhe Li , Muhammad Moin , Yangzhou Ma , Guangsheng Song
Li1.2Mn0.54Co0.13Ni0.13O2 (Li-rich Mn-based layered oxide) exhibits a high theoretical specific capacity, high operating voltage, and low cost, making it a promising candidate for next-generation cathodes in high-energy-density lithium-ion batteries. This study synthesized the cathode material coated with discontinuous ZrO2 nanoparticles via a co-precipitation method. Results demonstrate that the discontinuous ZrO2 nanoparticle coating significantly influences the electrochemical properties of Li1.2Mn0.54Co0.13Ni0.13O2. The optimal electrochemical performance, achieved with a 1.0 wt% ZrO2 discontinuous coating, delivered an initial discharge capacity of 196mAh g−1 and a capacity of 170.5mAh g−1 after 200 cycles at 1 C, corresponding to a high retention rate of 86.8 %. Furthermore, the discontinuous coating forms an intermittent protective layer while leaving substantial surface areas exposed. This morphology facilitates smoother and more numerous lithium-ion transport pathways, thereby maintaining high ionic conductivity and enhancing the cathode's electrochemical performance.
Li1.2Mn0.54Co0.13Ni0.13O2（富锂锰基层状氧化物）具有理论比容量高、工作电压高、成本低的特点，是高能量密度锂离子电池下一代阴极的理想材料。本研究采用共沉淀法合成了不连续ZrO2纳米颗粒包覆的正极材料。结果表明，不连续的ZrO2纳米颗粒涂层对Li1.2Mn0.54Co0.13Ni0.13O2的电化学性能有显著影响。在1.0 wt%的ZrO2不连续涂层中获得了最佳的电化学性能，在1 C下进行200次循环后，初始放电容量为196mAh g - 1，放电容量为170.5mAh g - 1，相应的保留率高达86.8% %。此外，不连续的涂层在留下大量暴露的表面区域的同时形成间歇性保护层。这种形态有利于更平滑和更多的锂离子传输路径，从而保持高离子电导率，提高阴极的电化学性能。
{"title":"Enhancing a high-energy Li-rich cathode for Li-ion batteries via discontinuous ZrO2 coating","authors":"Lu Sun , Ziyang Ma , Zhenfei Cai , Kai Li , Yuxin Lin , Qinyu Wu , Yanan Chen , Shimiao Chen , Junzhe Li , Muhammad Moin , Yangzhou Ma , Guangsheng Song","doi":"10.1016/j.jeurceramsoc.2026.118218","DOIUrl":"10.1016/j.jeurceramsoc.2026.118218","url":null,"abstract":"<div><div>Li<sub>1.2</sub>Mn<sub>0.54</sub>Co<sub>0.13</sub>Ni<sub>0.13</sub>O<sub>2</sub> (Li-rich Mn-based layered oxide) exhibits a high theoretical specific capacity, high operating voltage, and low cost, making it a promising candidate for next-generation cathodes in high-energy-density lithium-ion batteries. This study synthesized the cathode material coated with discontinuous ZrO<sub>2</sub> nanoparticles via a co-precipitation method. Results demonstrate that the discontinuous ZrO<sub>2</sub> nanoparticle coating significantly influences the electrochemical properties of Li<sub>1.2</sub>Mn<sub>0.54</sub>Co<sub>0.13</sub>Ni<sub>0.13</sub>O<sub>2</sub>. The optimal electrochemical performance, achieved with a 1.0 wt% ZrO<sub>2</sub> discontinuous coating, delivered an initial discharge capacity of 196mAh g<sup>−1</sup> and a capacity of 170.5mAh g<sup>−1</sup> after 200 cycles at 1 C, corresponding to a high retention rate of 86.8 %. Furthermore, the discontinuous coating forms an intermittent protective layer while leaving substantial surface areas exposed. This morphology facilitates smoother and more numerous lithium-ion transport pathways, thereby maintaining high ionic conductivity and enhancing the cathode's electrochemical performance.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 9","pages":"Article 118218"},"PeriodicalIF":6.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191591","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 : 2026-08-01Epub Date: 2026-02-02DOI: 10.1016/j.jeurceramsoc.2026.118206
F. Monteverde , S. Cassese , D. De Prisco , S. Mungiguerra , R. Savino
Compositionally complex (CC) AlB2-type diboride solid solutions (DSSs) containing IV-V-VI group metals were investigated as candidate materials for hypersonic applications using a ground entry simulator. Each CCDSS was composed of Ti and three other transition metals among Zr-Hf-Nb-Ta. Single phase CCDSS dense discs were spark plasma sintered and then exposed to a supersonic dissociated airflow (nominal Mach 3). The overall degradation of the discs was highly dependent on the combination of starting metals, and massive preferential oxidation occurred. The coexistence of Nb and Ta was detrimental. A thermal study was devised and implemented in a numerical model to validate the experimental set-up. The experimental results also showed good agreement with predictions based on a thermodynamic assessment.
{"title":"Searching the limits of compositionally complex AlB2-type diboride solid solutions for hypersonic applications","authors":"F. Monteverde , S. Cassese , D. De Prisco , S. Mungiguerra , R. Savino","doi":"10.1016/j.jeurceramsoc.2026.118206","DOIUrl":"10.1016/j.jeurceramsoc.2026.118206","url":null,"abstract":"<div><div>Compositionally complex (CC) AlB<sub>2</sub>-type diboride solid solutions (DSSs) containing IV-V-VI group metals were investigated as candidate materials for hypersonic applications using a ground entry simulator. Each CCDSS was composed of Ti and three other transition metals among Zr-Hf-Nb-Ta. Single phase CCDSS dense discs were spark plasma sintered and then exposed to a supersonic dissociated airflow (nominal Mach 3). The overall degradation of the discs was highly dependent on the combination of starting metals, and massive preferential oxidation occurred. The coexistence of Nb and Ta was detrimental. A thermal study was devised and implemented in a numerical model to validate the experimental set-up. The experimental results also showed good agreement with predictions based on a thermodynamic assessment.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 9","pages":"Article 118206"},"PeriodicalIF":6.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191593","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 : 2026-08-01Epub Date: 2026-02-12DOI: 10.1016/j.ijrmhm.2026.107727
Pejman Zamani, Meysam Khakian, Saeed Lak, Mohammad Amin Amjadi
The sequence of aging heat treatment for superalloy base metals and the application of hardface coatings pose significant challenges in the refurbishment of gas turbine blades. This study investigates the influence of an aging heat treatment of IN738 superalloy (845 °C, 24 h) on the microstructural features, mechanical characteristics, and tribological performance of HVOF-sprayed Cr₃C₂–NiCr coating. Microstructural and phase analyses were performed utilizing XRD, SEM, and EDS, while microhardness, fracture toughness, and ball-on-disc wear tests were conducted at room temperature and 550 °C. The as-sprayed coating consisted of Cr₃C₂, Cr₇C₃, and NiCr phases, whereas aging promoted the formation of Ni₃Cr, Cr₂₃C₆, and Cr₂O₃ phases through carbide coarsening and oxidation. These transformations resulted in a synergistic effect, leading to approximately a 20% reduction in hardness and a 50% decrease in fracture toughness, accompanied by a moderate increase in wear rate. At room temperature, the as-sprayed and aged coatings exhibited wear rates of 3.1 × 10−15 and 4.1 × 10−15 m3/N·m, respectively, whereas at 550 °C these values decreased to 2.0 × 10−15 and 3.0 × 10−15 m3/N·m. The as-sprayed coating exhibited predominantly abrasive and mild oxidative–adhesive wear, while the aged one showed adhesive transfer and oxide-assisted delamination. The findings suggest that the aging heat treatment of turbine superalloys should precede HVOF coating deposition to maintain the coating's microstructural integrity and high-temperature wear resistance.
{"title":"Correlation between microstructure, phase evolution, and high-temperature wear resistance of HVOF-sprayed Cr3C2-NiCr composite coatings subjected to superalloy aging treatment","authors":"Pejman Zamani, Meysam Khakian, Saeed Lak, Mohammad Amin Amjadi","doi":"10.1016/j.ijrmhm.2026.107727","DOIUrl":"10.1016/j.ijrmhm.2026.107727","url":null,"abstract":"<div><div>The sequence of aging heat treatment for superalloy base metals and the application of hardface coatings pose significant challenges in the refurbishment of gas turbine blades. This study investigates the influence of an aging heat treatment of IN738 superalloy (845 °C, 24 h) on the microstructural features, mechanical characteristics, and tribological performance of HVOF-sprayed Cr₃C₂–NiCr coating. Microstructural and phase analyses were performed utilizing XRD, SEM, and EDS, while microhardness, fracture toughness, and ball-on-disc wear tests were conducted at room temperature and 550 °C. The as-sprayed coating consisted of Cr₃C₂, Cr₇C₃, and NiCr phases, whereas aging promoted the formation of Ni₃Cr, Cr₂₃C₆, and Cr₂O₃ phases through carbide coarsening and oxidation. These transformations resulted in a synergistic effect, leading to approximately a 20% reduction in hardness and a 50% decrease in fracture toughness, accompanied by a moderate increase in wear rate. At room temperature, the as-sprayed and aged coatings exhibited wear rates of 3.1 × 10<sup>−15</sup> and 4.1 × 10<sup>−15</sup> m<sup>3</sup>/N·m, respectively, whereas at 550 °C these values decreased to 2.0 × 10<sup>−15</sup> and 3.0 × 10<sup>−15</sup> m<sup>3</sup>/N·m. The as-sprayed coating exhibited predominantly abrasive and mild oxidative–adhesive wear, while the aged one showed adhesive transfer and oxide-assisted delamination. The findings suggest that the aging heat treatment of turbine superalloys should precede HVOF coating deposition to maintain the coating's microstructural integrity and high-temperature wear resistance.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107727"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171514","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}
Zirconium (Zr) shows great promise for next-generation orthopedic implants due to its excellent biocompatibility, low elastic modulus, and low magnetic susceptibility. However, it is clinically constrained by high production costs and insufficient yield strength. Herein, a novel “impurity utilization + microalloying” strategy is proposed to optimize mechanical properties and reduce costs of Zr-based alloys while preserving biocompatibility and magnetic resonance imaging (MRI) compatibility. By leveraging the β-stabilizing effect of inherent impurities (Hf, Fe) in sponge zirconium (SZr) and atomic mobility inhibition by microalloying elements (Fe, Si, Mg), the brittle ω phase is suppressed in SZr-xNb-0.2 Mg-0.15Fe-0.1Si (SZNx) alloys, promoting formation of the intermediate β' phase (from β → ω transformation). Ultrafine/nanoscale β' plates induce precipitation and boundary strengthening, synergizing with solid solution strengthening from impurities and microalloying elements to enhance strength while maintaining low Young's modulus and good ductility. Consequently, SZNx alloys outperform ZrNb alloys fabricated from high-purity Zr (NZr) or unalloyed SZr in strength. Notably, the Zr-15Nb-0.25 Mg-0.15Fe-0.1Si (SZN15) alloy exhibits exceptional comprehensive properties: Young's modulus (E) = 58 ± 3 GPa, yield strength (YS) = 750 ± 18 MPa, elongation (EL) = 15.5 ± 1.6%. In vitro biocompatibility assessments show SZN15 cell viability exceeds 92% over all test periods, comparable to or better than clinically used Ti–6Al–4 V (TC4) and NZr. The mass magnetic susceptibility of SZNx alloys (1.27–1.90 × 10−6 cm3/g) is ∼50% that of TC4, ensuring excellent MRI compatibility. Most importantly, the cost of SZNx alloys is reduced by over 80% versus NZr-based alloys. This work offers an efficient, cost-effective strategy for developing low-cost, high-performance Zr-based orthopedic alloys, addressing the strength-modulus-ductility trade-off and cost barriers limiting clinical translation. .
{"title":"Optimization of mechanical properties and cost-reduction of potential orthopedic Zr alloys maintaining favorable biocompatibility through impurity utilization and microalloying","authors":"X.K. Liu , Z.C. Yin , S.X. Liang, Z.K. Zhou, Z.Y. Yuan, B.Y. Liu, Y.X. Guo, S.Z. Zhang, J.S. Zhang, X.Y. Zhang, R.P. Liu","doi":"10.1016/j.ijrmhm.2026.107687","DOIUrl":"10.1016/j.ijrmhm.2026.107687","url":null,"abstract":"<div><div>Zirconium (Zr) shows great promise for next-generation orthopedic implants due to its excellent biocompatibility, low elastic modulus, and low magnetic susceptibility. However, it is clinically constrained by high production costs and insufficient yield strength. Herein, a novel “impurity utilization + microalloying” strategy is proposed to optimize mechanical properties and reduce costs of Zr-based alloys while preserving biocompatibility and magnetic resonance imaging (MRI) compatibility. By leveraging the β-stabilizing effect of inherent impurities (Hf, Fe) in sponge zirconium (SZr) and atomic mobility inhibition by microalloying elements (Fe, Si, Mg), the brittle ω phase is suppressed in SZr-xNb-0.2 Mg-0.15Fe-0.1Si (SZNx) alloys, promoting formation of the intermediate β' phase (from β → ω transformation). Ultrafine/nanoscale β' plates induce precipitation and boundary strengthening, synergizing with solid solution strengthening from impurities and microalloying elements to enhance strength while maintaining low Young's modulus and good ductility. Consequently, SZNx alloys outperform Zr<img>Nb alloys fabricated from high-purity Zr (NZr) or unalloyed SZr in strength. Notably, the Zr-15Nb-0.25 Mg-0.15Fe-0.1Si (SZN15) alloy exhibits exceptional comprehensive properties: Young's modulus (E) = 58 ± 3 GPa, yield strength (YS) = 750 ± 18 MPa, elongation (EL) = 15.5 ± 1.6%. In vitro biocompatibility assessments show SZN15 cell viability exceeds 92% over all test periods, comparable to or better than clinically used Ti–6Al–4 V (TC4) and NZr. The mass magnetic susceptibility of SZNx alloys (1.27–1.90 × 10<sup>−6</sup> cm<sup>3</sup>/g) is ∼50% that of TC4, ensuring excellent MRI compatibility. Most importantly, the cost of SZNx alloys is reduced by over 80% versus NZr-based alloys. This work offers an efficient, cost-effective strategy for developing low-cost, high-performance Zr-based orthopedic alloys, addressing the strength-modulus-ductility trade-off and cost barriers limiting clinical translation.<!--> <!-->.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107687"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057556","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 : 2026-08-01Epub Date: 2026-01-22DOI: 10.1016/j.ijrmhm.2026.107691
Ruochong Wang , Yunan Fan , Zihan Yang , Weiwei He , Li Wang , Bin Liu , Yang Lu , Yong Liu
The influences of printing process on metallurgical quality and wear resistance of NiCu-diamond composites were quantitatively analyzed. The NiCu-diamond composite with low porosity (∼1.6 vol%) and low loss of diamond particles (only 0.5 vol%) was successfully fabricated, at an electron beam current of 2.4 mA, and a scanning rate of 1 m·s−1. The wear rate of the NiCu-diamond composite was as low as 5.0 × 10−7 mm3·N−1·m−1, and coefficients of friction (COFs) within 0.02–0.05. These values represent a substantial reduction compared to the corresponding values of 43.7 × 10−7 mm3·N−1·m−1 and 0.18–0.28. The dense tribofilm formed during wet friction (in 3.5 wt% NaCl solution) hinders further wear of the substrate, leading to lower COFs and wear rates than those of dry friction. The PBF-ed NiCu-diamond composites show excellent wet friction and wear properties with COFs lower than 0.04 and a wear rate of 1.6 × 10−7 mm3·N−1·m−1.
{"title":"Friction and wear behavior of NiCu-diamond composites fabricated by defect-controlled powder bed fusion (PBF) process","authors":"Ruochong Wang , Yunan Fan , Zihan Yang , Weiwei He , Li Wang , Bin Liu , Yang Lu , Yong Liu","doi":"10.1016/j.ijrmhm.2026.107691","DOIUrl":"10.1016/j.ijrmhm.2026.107691","url":null,"abstract":"<div><div>The influences of printing process on metallurgical quality and wear resistance of NiCu-diamond composites were quantitatively analyzed. The NiCu-diamond composite with low porosity (∼1.6 vol%) and low loss of diamond particles (only 0.5 vol%) was successfully fabricated, at an electron beam current of 2.4 mA, and a scanning rate of 1 m·s<sup>−1</sup>. The wear rate of the NiCu-diamond composite was as low as 5.0 × 10<sup>−7</sup> mm<sup>3</sup>·N<sup>−1</sup>·m<sup>−1</sup>, and coefficients of friction (COFs) within 0.02–0.05. These values represent a substantial reduction compared to the corresponding values of 43.7 × 10<sup>−7</sup> mm<sup>3</sup>·N<sup>−1</sup>·m<sup>−1</sup> and 0.18–0.28. The dense tribofilm formed during wet friction (in 3.5 wt% NaCl solution) hinders further wear of the substrate, leading to lower COFs and wear rates than those of dry friction. The PBF-ed NiCu-diamond composites show excellent wet friction and wear properties with COFs lower than 0.04 and a wear rate of 1.6 × 10<sup>−7</sup> mm<sup>3</sup>·N<sup>−1</sup>·m<sup>−1</sup>.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"138 ","pages":"Article 107691"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146032957","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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