Pub Date : 2024-11-21DOI: 10.1016/j.jallcom.2024.177654
Md. Shahwaz, Prekshya Nath, Indrani Sen
Ni-based superalloys exhibit exceptional high-temperature mechanical properties. A specific group, “Inconel superalloys,” has been a focus of extensive research owing to their ability to withstand high-temperatures, making them an inevitable candidate for aerospace applications. Superalloy components are traditionally manufactured through casting, forging, and post-machining, leading to material wastage and higher manufacturing costs. In this regard, additive manufacturing (AM) is increasingly used for fabricating complex shaped Inconel based components for critical aerospace application. AM is particularly advantageous for easy fabrication of intricate designs while having high material utilization, and reduced build time, still achieving controlled and targeted properties for expensive and difficult-to-machine Inconel superalloy components. Nevertheless, the complex layer-by-layer processing technique leads to completely different microstructural evolutions with respect to the as-cast counterparts which is also reflected in altered mechanical performance. This is particularly crucial considering that Inconel consists of different alloying elements, leading to the formation of multiple phases like γ, γ′ γ′′, etc. The current article reports a comprehensive overview of the following two topics: (i) commonly practiced AM techniques for fabricating Inconel superalloys and (ii) processing– microstructure–mechanical properties correlations for the most studied additively manufactured Inconel superalloys, IN718, IN625, IN738LC, and IN939. Special attention is dedicated in elucidating the influence of heat-treatment schedules on both the microstructure and mechanical properties of Inconel superalloys. This extensive research would prove beneficial in optimizing the types and processing parameters for AM of Inconel superalloys to attain the targeted microstructure, and phases, and also to design the suitable post-manufacturing heat-treatment schedule. Such correlation holds significant potential for realizing enhanced mechanical performance for additively manufactured Inconel components for industrial applications.
镍基超级合金具有优异的高温机械性能。英科耐尔超耐热合金 "是一个特殊的组别，由于具有耐高温的能力，使其成为航空航天应用的必然候选材料，一直是广泛研究的重点。超耐热合金部件传统上通过铸造、锻造和后加工制造，导致材料浪费和制造成本上升。在这方面，增材制造（AM）越来越多地用于制造复杂形状的因科镍合金组件，以满足关键的航空航天应用需求。对于昂贵且难以加工的因科镍尔超耐热合金部件来说，AM 尤其具有优势，它可以轻松制造复杂的设计，同时具有较高的材料利用率和较短的制造时间，还能实现可控的目标性能。然而，复杂的逐层加工技术会导致与铸件完全不同的微观结构演变，这也反映在机械性能的改变上。考虑到铬镍铁合金由不同的合金元素组成，会形成γ、γ′ γ′等多相，这一点尤为重要。本文全面概述了以下两个主题：(i) 制造因科镍尔超级合金的常用 AM 技术；(ii) 研究最多的添加剂制造因科镍尔超级合金 IN718、IN625、IN738LC 和 IN939 的加工-微观结构-力学性能相关性。研究还特别关注了热处理时间对因科镍尔超合金微观结构和机械性能的影响。这项广泛的研究将有助于优化因科镍尔超耐热合金 AM 的类型和加工参数，以实现目标微观结构和相位，并设计合适的制造后热处理计划。这种相关性为提高工业应用中铬镍铁合金增材制造部件的机械性能带来了巨大潜力。
{"title":"Recent Advances in Additive Manufacturing Technologies for Ni-Based Inconel Superalloys – A Comprehensive Review","authors":"Md. Shahwaz, Prekshya Nath, Indrani Sen","doi":"10.1016/j.jallcom.2024.177654","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177654","url":null,"abstract":"<em>Ni-based</em> superalloys exhibit exceptional high-temperature mechanical properties. A specific group, “Inconel superalloys,” has been a focus of extensive research owing to their ability to withstand high-temperatures, making them an inevitable candidate for aerospace applications. Superalloy components are traditionally manufactured through casting, forging, and post-machining, leading to material wastage and higher manufacturing costs. In this regard, additive manufacturing <em>(AM)</em> is increasingly used for fabricating complex shaped Inconel based components for critical aerospace application. <em>AM</em> is particularly advantageous for easy fabrication of intricate designs while having high material utilization, and reduced build time, still achieving controlled and targeted properties for expensive and difficult-to-machine Inconel superalloy components. Nevertheless, the complex layer-by-layer processing technique leads to completely different microstructural evolutions with respect to the as-cast counterparts which is also reflected in altered mechanical performance. This is particularly crucial considering that Inconel consists of different alloying elements, leading to the formation of multiple phases like γ, γ′ γ′′, etc. The current article reports a comprehensive overview of the following two topics: (i) commonly practiced <em>AM</em> techniques for fabricating Inconel superalloys and (ii) processing– microstructure–mechanical properties correlations for the most studied additively manufactured Inconel superalloys, <em>IN718</em>, <em>IN625</em>, <em>IN738LC</em>, and <em>IN939</em>. Special attention is dedicated in elucidating the influence of heat-treatment schedules on both the microstructure and mechanical properties of Inconel superalloys. This extensive research would prove beneficial in optimizing the types and processing parameters for <em>AM</em> of Inconel superalloys to attain the targeted microstructure, and phases, and also to design the suitable post-manufacturing heat-treatment schedule. Such correlation holds significant potential for realizing enhanced mechanical performance for additively manufactured Inconel components for industrial applications.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"63 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678176","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 : 2024-11-21DOI: 10.1016/j.jallcom.2024.177676
Gunasekaran Arunkumar, Lokeshraj Srinivasan, Govindan Deviga, Mariappan Mariappan, Mehboobali Pannipara, Abdullah G. Al-Sehemi, Savarimuthu Philip Anthony
Iron carbonate hydroxide-iron oxide hetero-phase bifunctional electrocatalyst was directly fabricated on nickel foam (NF), which exhibited strong urea oxidation reaction (UOR) and overall water splitting including sea water splitting. Hydrothermal method was adopted for fabrication of iron carbonate hydroxide-iron oxide catalyst (1-3) and deposition time was varied (3 h (1), 6 h (2) and 12 h (3)) to optimize the electrocatalytic activity. FTIR and X-ray photoelectron spectroscopic (XPS) analysis suggested the formation of iron carbonate hydroxide-iron oxide. OER studies revealed relatively strong activity for 1 compared to 2 and 3 in alkaline condition. 1 required the overpotential of 238 mV for producing the current density of 50 mA/cm2 whereas 2 and 3 needed 248 and 280 mV, respectively. In contrast, 3 showed strong HER activity that required overpotential of 301 mV to achieve 50 mA/cm2 whereas 2 and 1 needed 303 and 343 mV, respectively. Hence, 2 was chosen to fabricate overall water splitting and UOR. In presence of urea, 2 required low overpotential (130 mV) to produce 50 mA/cm2 current density. For overall water splitting, 2 needed 1.71 V to produce 10 mA/cm2 current density. The UOR combined cell required only 1.56 V to achieve 10 mA/cm2. Tafel slope, impedance and electrochemical active surface area (ECSA) calculation suggests improved kinetics with reduced charge transfer resistance and more active sites for 2. The stability studies indicated good stability of 2 in OER, HER and overall water splitting. After catalysis analysis indicated the formation of FeOOH and FeO active species during OER and HER, respectively. Thus, the present work developed a low-cost transition metal based bifunctional electrocatalyst for overall water splitting.
{"title":"Iron carbonate hydroxide-iron oxide hetero-phase catalyst: A bifunctional electrocatalyst for urea boosted overall water splitting","authors":"Gunasekaran Arunkumar, Lokeshraj Srinivasan, Govindan Deviga, Mariappan Mariappan, Mehboobali Pannipara, Abdullah G. Al-Sehemi, Savarimuthu Philip Anthony","doi":"10.1016/j.jallcom.2024.177676","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177676","url":null,"abstract":"Iron carbonate hydroxide-iron oxide hetero-phase bifunctional electrocatalyst was directly fabricated on nickel foam (NF), which exhibited strong urea oxidation reaction (UOR) and overall water splitting including sea water splitting. Hydrothermal method was adopted for fabrication of iron carbonate hydroxide-iron oxide catalyst (<strong>1-3</strong>) and deposition time was varied (3<!-- --> <!-- -->h (<strong>1</strong>), 6<!-- --> <!-- -->h (<strong>2</strong>) and 12<!-- --> <!-- -->h (<strong>3</strong>)) to optimize the electrocatalytic activity. FTIR and X-ray photoelectron spectroscopic (XPS) analysis suggested the formation of iron carbonate hydroxide-iron oxide. OER studies revealed relatively strong activity for <strong>1</strong> compared to <strong>2</strong> and <strong>3</strong> in alkaline condition. <strong>1</strong> required the overpotential of 238<!-- --> <!-- -->mV for producing the current density of 50<!-- --> <!-- -->mA/cm<sup>2</sup> whereas <strong>2</strong> and <strong>3</strong> needed 248 and 280<!-- --> <!-- -->mV, respectively. In contrast, <strong>3</strong> showed strong HER activity that required overpotential of 301<!-- --> <!-- -->mV to achieve 50<!-- --> <!-- -->mA/cm<sup>2</sup> whereas <strong>2</strong> and <strong>1</strong> needed 303 and 343<!-- --> <!-- -->mV, respectively. Hence, <strong>2</strong> was chosen to fabricate overall water splitting and UOR. In presence of urea, <strong>2</strong> required low overpotential (130<!-- --> <!-- -->mV) to produce 50<!-- --> <!-- -->mA/cm<sup>2</sup> current density. For overall water splitting, <strong>2</strong> needed 1.71<!-- --> <!-- -->V to produce 10<!-- --> <!-- -->mA/cm<sup>2</sup> current density. The UOR combined cell required only 1.56<!-- --> <!-- -->V to achieve 10<!-- --> <!-- -->mA/cm<sup>2</sup>. Tafel slope, impedance and electrochemical active surface area (ECSA) calculation suggests improved kinetics with reduced charge transfer resistance and more active sites for <strong>2</strong>. The stability studies indicated good stability of <strong>2</strong> in OER, HER and overall water splitting. After catalysis analysis indicated the formation of FeOOH and FeO active species during OER and HER, respectively. Thus, the present work developed a low-cost transition metal based bifunctional electrocatalyst for overall water splitting.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"73 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678254","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177695
Xuehuang Tang, Xiaowei Huang, Taifu Lang, Yujie Xie, Xin Lin, Yang Li, Yijian Zhou, Qun Yan, Kaixin Zhang, Chang Lin, Jie Sun
With the rapid advancement of display and smart lighting technologies, micro-light-emitting diodes (Micro-LEDs) have garnered substantial attention due to their exceptional performance characteristics. However, a significant challenge persists in achieving reliable interconnections between Micro-LED chips and driver backplanes. This article proposes and implements the Double-Layer Photoresist Structure Electroplating (DPSE) technique for fabricating Cu-SnAg metal bumps, thereby facilitating the heterogeneous integration of oxide thin film transistors (TFTs) with GaN-based blue LEDs. The DPSE process was optimized by addressing several critical factors, including the correlation between bump height and electroplating time, the occurrence of cracks in the photoresist surface, and the removal of the conductive layer. Metal bumps were successfully fabricated on TFT backplanes with dimensions of 16.5 μm × 10 μm, an average height of 5.39 μm, and a uniformity of approximately 2.266%. To demonstrate the efficacy of this approach, a 0.495-inch blue active-matrix Micro-LED display was designed and fabricated. This display features a mesa size of 15 µm × 30 µm, a pixel pitch of 222 µm, and a pixel density of 114 pixels per inch (PPI). The resultant blue Micro-LED display exhibits excellent optical characteristics, achieving a brightness of 1625 cd/m² (nits). It is anticipated that the methodology and findings presented in this study will contribute significantly to the advancement of Micro-LED display technology in consumer electronics. This research not only represents a significant advancement in the field of Micro-LED display technology, but also paves the way for future innovations in high-resolution, energy-efficient display systems.
{"title":"Active-matrix TFT driven GaN blue Micro-LED display realized with electroplated copper-tin-silver micro bumps-based bonding structure","authors":"Xuehuang Tang, Xiaowei Huang, Taifu Lang, Yujie Xie, Xin Lin, Yang Li, Yijian Zhou, Qun Yan, Kaixin Zhang, Chang Lin, Jie Sun","doi":"10.1016/j.jallcom.2024.177695","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177695","url":null,"abstract":"With the rapid advancement of display and smart lighting technologies, micro-light-emitting diodes (Micro-LEDs) have garnered substantial attention due to their exceptional performance characteristics. However, a significant challenge persists in achieving reliable interconnections between Micro-LED chips and driver backplanes. This article proposes and implements the Double-Layer Photoresist Structure Electroplating (DPSE) technique for fabricating Cu-SnAg metal bumps, thereby facilitating the heterogeneous integration of oxide thin film transistors (TFTs) with GaN-based blue LEDs. The DPSE process was optimized by addressing several critical factors, including the correlation between bump height and electroplating time, the occurrence of cracks in the photoresist surface, and the removal of the conductive layer. Metal bumps were successfully fabricated on TFT backplanes with dimensions of 16.5 μm × 10 μm, an average height of 5.39 μm, and a uniformity of approximately 2.266%. To demonstrate the efficacy of this approach, a 0.495-inch blue active-matrix Micro-LED display was designed and fabricated. This display features a mesa size of 15<!-- --> <!-- -->µm × 30<!-- --> <!-- -->µm, a pixel pitch of 222<!-- --> <!-- -->µm, and a pixel density of 114 pixels per inch (PPI). The resultant blue Micro-LED display exhibits excellent optical characteristics, achieving a brightness of 1625<!-- --> <!-- -->cd/m² (nits). It is anticipated that the methodology and findings presented in this study will contribute significantly to the advancement of Micro-LED display technology in consumer electronics. This research not only represents a significant advancement in the field of Micro-LED display technology, but also paves the way for future innovations in high-resolution, energy-efficient display systems.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"19 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673342","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177688
Yanping Wang, Xihai Li, Hong Yan, Boyu Liu, Zhiwei Shan, Rongshi Chen
The Mg-2.10Zn-0.58Ca-1.02Zr-10.34SiCp (wt%, SiCp/ZX20K) composites were fabricated by stir casting and hot extruded at 400 °C with extrusion speed of 5 mm/s and 10 mm/s, respectively. The SiC particles, which initially exhibited a necklace-type distribution at the grain boundaries, transformed into a band-type distribution after hot extrusion. The SiCp/ZX20K composites underwent complete recrystallization, resulting in a pronounced bimodal microstructure consisting of coarse secondary recrystallized grains in the SiC-poor region and fine grains in the SiC-rich regions. A basal plane fiber texture was achieved, with the {0001} plane oriented parallel to the transverse direction (TD). Moreover, grains with their <2-1-10> orientation parallel to the extrusion direction (ED) experienced preferred growth because those grains possessed characteristics such as larger initial size, lower storage energy, and a larger orientation difference from neighboring grains. The SiCp/ZX20K composites extruded at 5 mm/s exhibited a yield strength (YS) of 218 MPa, with a decent elongation to failure (EL) of 4.8% and an ultimate tensile strength (UTS) of 294 MPa which was 2.3 times greater than that of the as-cast state. Increasing the extrusion speed resulted in better overall mechanical properties and reduced the anisotropy in mechanical properties, due to the combined effects of texture, particle orientation and particle distribution.
{"title":"Microstructure, texture and mechanical properties of Mg-2.10Zn-0.58Ca-1.02Zr-10.34SiCp (wt%) composites after being extruded at different speeds","authors":"Yanping Wang, Xihai Li, Hong Yan, Boyu Liu, Zhiwei Shan, Rongshi Chen","doi":"10.1016/j.jallcom.2024.177688","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177688","url":null,"abstract":"The Mg-2.10Zn-0.58Ca-1.02Zr-10.34SiC<sub>p</sub> (wt%, SiC<sub>p</sub>/ZX20K) composites were fabricated by stir casting and hot extruded at 400 °C with extrusion speed of 5<!-- --> <!-- -->mm/s and 10<!-- --> <!-- -->mm/s, respectively. The SiC particles, which initially exhibited a necklace-type distribution at the grain boundaries, transformed into a band-type distribution after hot extrusion. The SiC<sub>p</sub>/ZX20K composites underwent complete recrystallization, resulting in a pronounced bimodal microstructure consisting of coarse secondary recrystallized grains in the SiC-poor region and fine grains in the SiC-rich regions. A basal plane fiber texture was achieved, with the {0001} plane oriented parallel to the transverse direction (TD). Moreover, grains with their <2-1-10> orientation parallel to the extrusion direction (ED) experienced preferred growth because those grains possessed characteristics such as larger initial size, lower storage energy, and a larger orientation difference from neighboring grains. The SiC<sub>p</sub>/ZX20K composites extruded at 5<!-- --> <!-- -->mm/s exhibited a yield strength (YS) of 218<!-- --> <!-- -->MPa, with a decent elongation to failure (EL) of 4.8% and an ultimate tensile strength (UTS) of 294<!-- --> <!-- -->MPa which was 2.3 times greater than that of the as-cast state. Increasing the extrusion speed resulted in better overall mechanical properties and reduced the anisotropy in mechanical properties, due to the combined effects of texture, particle orientation and particle distribution.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"251 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673347","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177693
Yang Zhao, Jiahui Zhang, Chengle Song, Guojiao Xiang, Chenfei Jiao, Meibo Xin, Fujing Dong, Zhikang Huang, Mingkun Wang, Hui Wang
GaN-based light-emitting diodes (LEDs) have important applications in medical diagnostics, sterilization, and other fields. However, the mismatch of p-type materials usually makes it difficult for conventional pn-type GaN-based LEDs to obtain pure ultraviolet (UV) emission. In this paper, a series of metal-insulator-semiconductor (MIS)-type diodes with Au/i-AlN/n-GaN structure were prepared by varying the deposition time of AlN films, and the effects of ambient temperature on their electrical and electroluminescence (EL) properties were investigated. The Au/i-AlN/n-GaN diode achieved high-purity UV emission, and the device had the lowest turn-on voltage and the strongest EL intensity when the deposition time of AlN is 40 min. In addition, the effect of ambient temperature on the EL performance of the MIS-type LED was investigated, and the emission was attenuated due to thermal effects at temperatures above 40℃. Finally, we clarified the source of holes from the energy band structure and discussed the luminescence mechanism of the device. The results show that the MIS structure is an attractive choice to effectively realize the UV emission of GaN-based LEDs.
氮化镓基发光二极管（LED）在医疗诊断、消毒等领域有着重要的应用。然而，由于 p 型材料的不匹配，传统的 pn 型氮化镓基发光二极管通常难以获得纯紫外线（UV）发射。本文通过改变 AlN 薄膜的沉积时间，制备了一系列具有 Au/i-AlN/n-GaN 结构的金属绝缘体半导体（MIS）型二极管，并研究了环境温度对其电学和电致发光（EL）特性的影响。当 AlN 的沉积时间为 40 分钟时，Au/i-AlN/n-GaN 二极管实现了高纯度的紫外发射，该器件的开启电压最低，电致发光强度最强。此外，我们还研究了环境温度对 MIS 型发光二极管电致发光性能的影响，结果表明，在温度高于 40℃ 时，由于热效应，发射会减弱。最后，我们从能带结构上阐明了空穴的来源，并讨论了该器件的发光机理。结果表明，MIS 结构是有效实现氮化镓基发光二极管紫外发射的一个有吸引力的选择。
{"title":"Study on the fabrication of UV LED based on Au/i-AlN/n-GaN structure and the effect of operating temperature on the carrier transmission and electroluminescence characteristics","authors":"Yang Zhao, Jiahui Zhang, Chengle Song, Guojiao Xiang, Chenfei Jiao, Meibo Xin, Fujing Dong, Zhikang Huang, Mingkun Wang, Hui Wang","doi":"10.1016/j.jallcom.2024.177693","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177693","url":null,"abstract":"GaN-based light-emitting diodes (LEDs) have important applications in medical diagnostics, sterilization, and other fields. However, the mismatch of p-type materials usually makes it difficult for conventional pn-type GaN-based LEDs to obtain pure ultraviolet (UV) emission. In this paper, a series of metal-insulator-semiconductor (MIS)-type diodes with Au/i-AlN/n-GaN structure were prepared by varying the deposition time of AlN films, and the effects of ambient temperature on their electrical and electroluminescence (EL) properties were investigated. The Au/i-AlN/n-GaN diode achieved high-purity UV emission, and the device had the lowest turn-on voltage and the strongest EL intensity when the deposition time of AlN is 40<!-- --> <!-- -->min. In addition, the effect of ambient temperature on the EL performance of the MIS-type LED was investigated, and the emission was attenuated due to thermal effects at temperatures above 40℃. Finally, we clarified the source of holes from the energy band structure and discussed the luminescence mechanism of the device. The results show that the MIS structure is an attractive choice to effectively realize the UV emission of GaN-based LEDs.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"81 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678256","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177687
Qiwei Sun, Qiuyan Yi, Hang Luo, Qiong Liu, Dou Zhang
The sintering temperature of solid-state synthesis exceeds 1000 ℃, which easily leads to the formation of oxygen vacancies. The presence of oxygen vacancies can alter the electronic/crystal structure and surface chemical properties of perovskite oxides. In this work, the content of oxygen vacancy of NaNbO3 are controlled by adjusting the heat treatment conditions including atmosphere, temperature, and time. XPS and EPR are used to analyze the relative content of oxygen vacancies. The N2 heat treatment time is 3 hours, and as the temperature increases from 300 ℃ to 900 ℃, the oxygen vacancy content increases from 16.4% to 18.9%. At 900 ℃, the time is extended to 5 hours, and the oxygen vacancy content increased to 26.4%. The disordered outer structure in HRTEM images confirms the existence of oxygen vacancies. The effect of the presence of oxygen vacancy on the efficiency of piezocatalysis and piezo-photocatalysis of NaNbO3 is cleared. The NaNbO3 sample heat-treated in N2 for 3 hours (named NN-3h N2) showed the best piezo-photocatalytic performance, with a rate constant (k) of 0.19175 min-1, which is much higher than the unmodified NaNbO3 (0.11777 min-1). The electrochemical test results show that the NN-3h N2 sample has better charge transfer ability and stronger photocurrent response, indicating that the presence of oxygen vacancies improves the migration and transfer efficiency of charge carriers. The volcanic trend indicates that an appropriate oxygen vacancy content is beneficial to the improvement of piezo-photocatalytic performance.
{"title":"Improved piezo-photocatalytic activity by controlling the oxygen vacancy content of NaNbO3 powders","authors":"Qiwei Sun, Qiuyan Yi, Hang Luo, Qiong Liu, Dou Zhang","doi":"10.1016/j.jallcom.2024.177687","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177687","url":null,"abstract":"The sintering temperature of solid-state synthesis exceeds 1000 ℃, which easily leads to the formation of oxygen vacancies. The presence of oxygen vacancies can alter the electronic/crystal structure and surface chemical properties of perovskite oxides. In this work, the content of oxygen vacancy of NaNbO<sub>3</sub> are controlled by adjusting the heat treatment conditions including atmosphere, temperature, and time. XPS and EPR are used to analyze the relative content of oxygen vacancies. The N<sub>2</sub> heat treatment time is 3<!-- --> <!-- -->hours, and as the temperature increases from 300 ℃ to 900 ℃, the oxygen vacancy content increases from 16.4% to 18.9%. At 900 ℃, the time is extended to 5<!-- --> <!-- -->hours, and the oxygen vacancy content increased to 26.4%. The disordered outer structure in HRTEM images confirms the existence of oxygen vacancies. The effect of the presence of oxygen vacancy on the efficiency of piezocatalysis and piezo-photocatalysis of NaNbO<sub>3</sub> is cleared. The NaNbO<sub>3</sub> sample heat-treated in N<sub>2</sub> for 3<!-- --> <!-- -->hours (named NN-3h N<sub>2</sub>) showed the best piezo-photocatalytic performance, with a rate constant (k) of 0.19175<!-- --> <!-- -->min<sup>-1</sup>, which is much higher than the unmodified NaNbO<sub>3</sub> (0.11777<!-- --> <!-- -->min<sup>-1</sup>). The electrochemical test results show that the NN-3h N<sub>2</sub> sample has better charge transfer ability and stronger photocurrent response, indicating that the presence of oxygen vacancies improves the migration and transfer efficiency of charge carriers. The volcanic trend indicates that an appropriate oxygen vacancy content is beneficial to the improvement of piezo-photocatalytic performance.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"42 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673337","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177690
Hae In Choi, Jae Ho Han, Chae Yeon Lee, Myang Hwan Lee, Tae Kwon Song, Yun Sang Lee
The presence of secondary phases in rare-earth ion-doped potassium sodium niobate ((K0.5Na0.5)NbO3, KNN) ceramics limit its electronic applications. To address this limitation, we investigated the electronic and luminescence properties of Eu3+-doped KNN (KNEN) ceramics. We synthesized a high-purity perovskite phase of KNEN without secondary phases by carefully adjusting the Na and K concentrations with 1 mol% Eu. KNEN ceramics demonstrated excellent ferroelectric and luminescent properties, including a photochromic effect that presented reversible color changes on exposure to ultraviolet light and X-rays. Further, we observed a strong correlation between the electric and luminescent properties near the orthorhombic-tetragonal phase transition at ~200 °C. These results suggest that KNEN ceramics are promising Pb-free luminescent piezoelectric materials.
稀土离子掺杂的铌酸钠钾（(K0.5Na0.5)NbO3，KNN）陶瓷中存在的次生相限制了其电子应用。为了解决这一限制，我们研究了掺杂 Eu3+ 的铌酸钠钾（KNEN）陶瓷的电子和发光特性。我们通过仔细调节 Na 和 K 的浓度，用 1 mol% 的 Eu 合成了不含次生相的高纯度 KNEN 包晶相。KNEN 陶瓷具有出色的铁电和发光特性，包括光致变色效应，在紫外线和 X 射线照射下会呈现可逆的颜色变化。此外，我们还观察到，在约 200 °C 的正方-四方相变附近，电学特性和发光特性之间存在很强的相关性。这些结果表明，KNEN 陶瓷是一种很有前途的无铅发光压电材料。
{"title":"Synthesis and Characterization of Eu-Doped (K0.5Na0.5)NbO3 Ceramics with Enhanced Ferroelectric, Photochromic, and Luminescent Properties","authors":"Hae In Choi, Jae Ho Han, Chae Yeon Lee, Myang Hwan Lee, Tae Kwon Song, Yun Sang Lee","doi":"10.1016/j.jallcom.2024.177690","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177690","url":null,"abstract":"The presence of secondary phases in rare-earth ion-doped potassium sodium niobate ((K<sub>0.5</sub>Na<sub>0.5</sub>)NbO<sub>3</sub>, KNN) ceramics limit its electronic applications. To address this limitation, we investigated the electronic and luminescence properties of Eu<sup>3+</sup>-doped KNN (KNEN) ceramics. We synthesized a high-purity perovskite phase of KNEN without secondary phases by carefully adjusting the Na and K concentrations with 1<!-- --> <!-- -->mol% Eu. KNEN ceramics demonstrated excellent ferroelectric and luminescent properties, including a photochromic effect that presented reversible color changes on exposure to ultraviolet light and X-rays. Further, we observed a strong correlation between the electric and luminescent properties near the orthorhombic-tetragonal phase transition at ~200 °C. These results suggest that KNEN ceramics are promising Pb-free luminescent piezoelectric materials.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"74 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678949","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177677
Tianwei Zhao, Gang Cheng, Wuxia Zhang, Jinyan Xiong
Hollow-structured TiO2 is promising for photocatalytic CO2 reduction due to its high surface area and light absorption. This study aims to enhance its photocatalytic activity through the engineering of Cu and CuAg alloy cocatalysts. Hollow TiO2 was synthesized by a hard template method, followed by Cu loading and CuAg alloy formation via a chemical replacement reaction. The optimal 7% Cu loading achieved the highest CH4 yield of 2.47 μmol g-1 h-1 among the TiO2-Cu composites. Introducing Ag further enhanced the performance, with the Cu:Ag= 9:1 alloy boosting the CH4 yield to 6.72 μmol g-1 h-1, approximately 14 times that of pure TiO2. Characterization techniques such as XRD, SEM, and XPS were also employed to analyze the phase composition, microstructure, and photoelectrochemical properties of the synthesized materials. The experimental findings indicate that the introduction of the CuAg alloy significantly promotes charge separation and transfer efficiency, and increases the effective active sites on the TiO2 surface, thereby greatly enhancing the efficiency of the photocatalytic reaction. These findings offer insights into the design of efficient photocatalytic materials for sustainable energy applications.
{"title":"Cocatalysts engineering promotes photocatalytic CO2 reduction of hollow TiO2 nanospheres: From Cu nanoparticles to CuAg species","authors":"Tianwei Zhao, Gang Cheng, Wuxia Zhang, Jinyan Xiong","doi":"10.1016/j.jallcom.2024.177677","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177677","url":null,"abstract":"Hollow-structured TiO<sub>2</sub> is promising for photocatalytic CO<sub>2</sub> reduction due to its high surface area and light absorption. This study aims to enhance its photocatalytic activity through the engineering of Cu and CuAg alloy cocatalysts. Hollow TiO<sub>2</sub> was synthesized by a hard template method, followed by Cu loading and CuAg alloy formation via a chemical replacement reaction. The optimal 7% Cu loading achieved the highest CH<sub>4</sub> yield of 2.47 μmol g<sup>-1</sup> h<sup>-1</sup> among the TiO<sub>2</sub>-Cu composites. Introducing Ag further enhanced the performance, with the Cu:Ag= 9:1 alloy boosting the CH<sub>4</sub> yield to 6.72 μmol g<sup>-1</sup> h<sup>-1</sup>, approximately 14 times that of pure TiO<sub>2</sub>. Characterization techniques such as XRD, SEM, and XPS were also employed to analyze the phase composition, microstructure, and photoelectrochemical properties of the synthesized materials. The experimental findings indicate that the introduction of the CuAg alloy significantly promotes charge separation and transfer efficiency, and increases the effective active sites on the TiO<sub>2</sub> surface, thereby greatly enhancing the efficiency of the photocatalytic reaction. These findings offer insights into the design of efficient photocatalytic materials for sustainable energy applications.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"18 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673344","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 : 2024-11-20DOI: 10.1016/j.jallcom.2024.177678
Yonglei Xing, Chunlin Li, Xiaojing Jiang, Xiaoyong Jin, Yage Peng, Beibei Kou, Gang Ni
The strong electronic interactions between metal oxide components are crucial for the activation of peroxymonosulfate (PMS) in pollutant degradation. In this study, an innovative MnOOH/CoOOH composite material (labeled as B-MCo-0.1) was synthesized through mesoscale chemical coupling, serving as an efficient PMS activator for phenol degradation. Experimental findings suggest that CoOOH nanosheets incorporated on MnOOH surface prevent CoOOH aggregation, increase specific surface area, and enhance the synergistic interaction between components, thereby improving activation and degradation efficiency. Under optimal conditions, a 50 mL phenol solution (25 mg/L) can achieve 100% degradation within 10 minutes. XPS analysis reveals that the robust electronic interaction between CoOOH and MnOOH facilitates PMS activation, generating reactive oxygen species (ROS) that effectively degrade phenol through both non-radical and radical pathways. Experiments, including quenching tests, electrochemical analysis, electron paramagnetic resonance (EPR) measurements, and sulfoxide method experiments for identifying high-valent metal oxides confirm that singlet oxygen (1O2) and superoxide anion (·O2−) play major roles in this process. Additionally, high-valent manganese oxides and electron transfer complexes on the catalyst surface, generated under strong electronic interactions, also contribute significantly to phenol degradation. By exploring the pivotal role of robust electronic interactions in activating PMS, this study extends the potential applications of MnOOH-based materials in environmental remediation.
{"title":"Enhanced Peroxymonosulfate Activation by MnOOH/CoOOH Composites for Efficient Phenol Degradation: Mechanistic Insights and Practical Implications","authors":"Yonglei Xing, Chunlin Li, Xiaojing Jiang, Xiaoyong Jin, Yage Peng, Beibei Kou, Gang Ni","doi":"10.1016/j.jallcom.2024.177678","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177678","url":null,"abstract":"The strong electronic interactions between metal oxide components are crucial for the activation of peroxymonosulfate (PMS) in pollutant degradation. In this study, an innovative MnOOH/CoOOH composite material (labeled as B-MCo-0.1) was synthesized through mesoscale chemical coupling, serving as an efficient PMS activator for phenol degradation. Experimental findings suggest that CoOOH nanosheets incorporated on MnOOH surface prevent CoOOH aggregation, increase specific surface area, and enhance the synergistic interaction between components, thereby improving activation and degradation efficiency. Under optimal conditions, a 50<!-- --> <!-- -->mL phenol solution (25<!-- --> <!-- -->mg/L) can achieve 100% degradation within 10<!-- --> <!-- -->minutes. XPS analysis reveals that the robust electronic interaction between CoOOH and MnOOH facilitates PMS activation, generating reactive oxygen species (ROS) that effectively degrade phenol through both non-radical and radical pathways. Experiments, including quenching tests, electrochemical analysis, electron paramagnetic resonance (EPR) measurements, and sulfoxide method experiments for identifying high-valent metal oxides confirm that singlet oxygen (<sup>1</sup>O<sub>2</sub>) and superoxide anion (·O<sub>2</sub><sup>−</sup>) play major roles in this process. Additionally, high-valent manganese oxides and electron transfer complexes on the catalyst surface, generated under strong electronic interactions, also contribute significantly to phenol degradation. By exploring the pivotal role of robust electronic interactions in activating PMS, this study extends the potential applications of MnOOH-based materials in environmental remediation.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"43 2 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673348","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}
Carbon-based transition-metal electrocatalysts are regarded as promising candidates for catalyzing oxygen reduction reaction (ORR), yet their electrocatalytic ORR performances are greatly limited by active sites utilization caused by the metal aggregation and pore collapse under high temperature. This study rationally designed a cobalt-based ORR catalyst supported on a g-C3N4/carbon nanotube (CNT) network as a cost-effective alternative of platinum-based catalysts. CNT were embedded into the lamellar precursor of melamine and cyanuric acid, and a synergistic effect between CNT and precursor was realized to regulate the density and activity of active sites. The polycondensation of precursors led to the formation of an "interlocking" structure of CNT supports with abundant exposed defects, allowing for effectively anchoring cobalt ions to generate Co-Nx sites. Meanwhile, partial Co ions underwent reconstruction and transportation to form Co nanoparticles and extended the disruptive CNT structure, exposing more interfacial defects to enhance the ORR catalytic properties. The prepared Co@g-C3N4/CNT catalyst demonstrated impressive ORR activity comparable to commercial Pt/C catalyst, showing superior stability. This research offers a promising approach for engineering interfacial defects to synthesize high-performance non-precious metal electrocatalysts for energy conversion applications.
{"title":"Leveraging Interlocking Structural Defects of g-C3N4/CNT Networks: Toward Enhanced Oxygen Reduction Activity of the Cobalt-Based Electrocatalyst","authors":"Zhengyu Wei, Pingyi Feng, Lingzhe Meng, Xuelin Gong, Faheem Naseem, Xue Qin, Wei Wei","doi":"10.1016/j.jallcom.2024.177696","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177696","url":null,"abstract":"Carbon-based transition-metal electrocatalysts are regarded as promising candidates for catalyzing oxygen reduction reaction (ORR), yet their electrocatalytic ORR performances are greatly limited by active sites utilization caused by the metal aggregation and pore collapse under high temperature. This study rationally designed a cobalt-based ORR catalyst supported on a g-C<sub>3</sub>N<sub>4</sub>/carbon nanotube (CNT) network as a cost-effective alternative of platinum-based catalysts. CNT were embedded into the lamellar precursor of melamine and cyanuric acid, and a synergistic effect between CNT and precursor was realized to regulate the density and activity of active sites. The polycondensation of precursors led to the formation of an \"interlocking\" structure of CNT supports with abundant exposed defects, allowing for effectively anchoring cobalt ions to generate Co-N<sub>x</sub> sites. Meanwhile, partial Co ions underwent reconstruction and transportation to form Co nanoparticles and extended the disruptive CNT structure, exposing more interfacial defects to enhance the ORR catalytic properties. The prepared Co@g-C<sub>3</sub>N<sub>4</sub>/CNT catalyst demonstrated impressive ORR activity comparable to commercial Pt/C catalyst, showing superior stability. This research offers a promising approach for engineering interfacial defects to synthesize high-performance non-precious metal electrocatalysts for energy conversion applications.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"71 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678257","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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