I. Campos-Silva, J. Cedeño-Velázquez, A. D. Contla-Pacheco, I. Arzate-Vázquez, L. E. Castillo-Vela, M. Olivares-Luna, J. L. Rosales-Lopez, F. P. Espino-Cortes
In this study, novel findings were obtained regarding the influence of a 10 A current intensity on the growth of an FeB–Fe2B layer during pulsed-DC powder-pack boriding. Boride layer formation was carried out on AISI 316 L steel at 1123–1223 K for different exposure times at each temperature, considering 10 s polarity inversion cycles. The boride layer was characterized by x-ray diffraction and high-speed Berkovich nanoindentation, the latter being used to determine the hardness and reduced Young’s modulus mappings along the depth of the layer-substrate system. Moreover, the growth kinetics of the FeB–Fe2B layer on the steel’s surface was modeled using the heat balance integral method (HBIM). This involved transforming Fick’s second law into ordinary differential equations over time, assuming a quadratic boron concentration profile in space to determine the B diffusion coefficients in FeB and Fe2B, respectively. From the Arrhenius relationship, the B activation energies in the boride layer were estimated considering the contribution of the electromigration effect; the results showed an approximately 30% reduction compared to the values obtained in the conventional powder-pack boriding for AISI 316 L steel. Finally, the theoretical layer thickness obtained by the HBIM demonstrated an error of no more than 5% against the experimental FeB and FeB + Fe2B layer thickness values.
本研究就脉冲直流粉末包硼化过程中 10 A 电流强度对 FeB-Fe2B 层生长的影响获得了新的发现。在 1123-1223 K 的 AISI 316 L 钢上形成了硼化物层，每个温度下的暴露时间不同，极性反转周期为 10 秒。通过 X 射线衍射和高速 Berkovich 纳米压痕法对硼化物层进行了表征，后者用于确定硼化物层-基底系统沿深度方向的硬度和还原杨氏模量映射。此外，还使用热平衡积分法（HBIM）对钢表面的 FeB-Fe2B 层的生长动力学进行了建模。这包括将菲克第二定律转化为随时间变化的常微分方程，假设空间中的硼浓度曲线为二次曲线，以分别确定铁硼和铁二硼中的硼扩散系数。根据阿伦尼乌斯关系，考虑到电迁移效应的贡献，对硼化物层中的硼活化能进行了估算；结果表明，与 AISI 316 L 钢的传统粉末包硼化物相比，硼活化能降低了约 30%。最后，HBIM 得出的理论硼化物层厚度与实验得出的 FeB 和 FeB + Fe2B 层厚度值相比，误差不超过 5%。
{"title":"Microstructural and kinetics analysis of FeB–Fe2B layer grown by pulsed-DC powder-pack boriding on AISI 316 L steel","authors":"I. Campos-Silva, J. Cedeño-Velázquez, A. D. Contla-Pacheco, I. Arzate-Vázquez, L. E. Castillo-Vela, M. Olivares-Luna, J. L. Rosales-Lopez, F. P. Espino-Cortes","doi":"10.1116/6.0003774","DOIUrl":"https://doi.org/10.1116/6.0003774","url":null,"abstract":"In this study, novel findings were obtained regarding the influence of a 10 A current intensity on the growth of an FeB–Fe2B layer during pulsed-DC powder-pack boriding. Boride layer formation was carried out on AISI 316 L steel at 1123–1223 K for different exposure times at each temperature, considering 10 s polarity inversion cycles. The boride layer was characterized by x-ray diffraction and high-speed Berkovich nanoindentation, the latter being used to determine the hardness and reduced Young’s modulus mappings along the depth of the layer-substrate system. Moreover, the growth kinetics of the FeB–Fe2B layer on the steel’s surface was modeled using the heat balance integral method (HBIM). This involved transforming Fick’s second law into ordinary differential equations over time, assuming a quadratic boron concentration profile in space to determine the B diffusion coefficients in FeB and Fe2B, respectively. From the Arrhenius relationship, the B activation energies in the boride layer were estimated considering the contribution of the electromigration effect; the results showed an approximately 30% reduction compared to the values obtained in the conventional powder-pack boriding for AISI 316 L steel. Finally, the theoretical layer thickness obtained by the HBIM demonstrated an error of no more than 5% against the experimental FeB and FeB + Fe2B layer thickness values.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141831401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Cu-Fe binary alloys exhibit severe elemental segregation, resulting in an inhomogeneous microstructure, which leads to differences in microregion magnetic properties, thus affecting their application. Employing magnetron sputtering to produce films is advantageous for achieving a consistent dispersion of Fe within the Cu matrix. Furthermore, the addition of Ni will result in a more uniform distribution of Fe and facilitate the formation of the ferromagnetic Ni3Fe phase. In this study, Cu100−xFex and Cu100−x(Ni3/4Fe1/4)x series films were prepared by magnetron sputtering technique. The magnetic properties of films are closely related to their ferromagnetic element content. An increase in the content of ferromagnetic elements leads to an improvement in the saturation magnetization (MS) strength and a decrease in the coercivity (HC). The formation of Fe-Fe pairs is more favorable for magnetic properties compared to Ni-Fe pairs. Meanwhile, by comparing with bulk alloys, the distribution of the magnetic elements severely affects the magnetic properties. Moreover, the resistivity of Cu100−xFex films (20.3–96.7 μΩ cm) is much higher than that of Cu100−x(Ni3/4Fe1/4)x films (15.6–60.6 μΩ cm), which depends on the magnetic properties. This study systematically analyzes the effect of the content and distribution of magnetic elements on magnetic and electrical properties.
{"title":"Studies of electrical resistivity and magnetic properties of CuFe and CuNiFe films prepared by magnetron sputtering","authors":"Muhammad Saqib Shahzad, Xiao Wang, Yinglin Hu, Xiaona Li, Qiao Jiang, Min Li, Zhumin Li, Renwei Liu, Rui Zheng, Chuang Dong","doi":"10.1116/6.0003684","DOIUrl":"https://doi.org/10.1116/6.0003684","url":null,"abstract":"The Cu-Fe binary alloys exhibit severe elemental segregation, resulting in an inhomogeneous microstructure, which leads to differences in microregion magnetic properties, thus affecting their application. Employing magnetron sputtering to produce films is advantageous for achieving a consistent dispersion of Fe within the Cu matrix. Furthermore, the addition of Ni will result in a more uniform distribution of Fe and facilitate the formation of the ferromagnetic Ni3Fe phase. In this study, Cu100−xFex and Cu100−x(Ni3/4Fe1/4)x series films were prepared by magnetron sputtering technique. The magnetic properties of films are closely related to their ferromagnetic element content. An increase in the content of ferromagnetic elements leads to an improvement in the saturation magnetization (MS) strength and a decrease in the coercivity (HC). The formation of Fe-Fe pairs is more favorable for magnetic properties compared to Ni-Fe pairs. Meanwhile, by comparing with bulk alloys, the distribution of the magnetic elements severely affects the magnetic properties. Moreover, the resistivity of Cu100−xFex films (20.3–96.7 μΩ cm) is much higher than that of Cu100−x(Ni3/4Fe1/4)x films (15.6–60.6 μΩ cm), which depends on the magnetic properties. This study systematically analyzes the effect of the content and distribution of magnetic elements on magnetic and electrical properties.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141267048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fei Zhou, Yang Li, Haizeng Song, Xianhua Wei, Bo Dai
Two-dimensional (2D) KNbO3 is prepared by topotactic transition from 2D KNbO2 at 530 °C in air, which has a single spontaneous polarization (Ps) direction along the [101¯]pc zone axis. The strong Ps anisotropy leads to a negligible second harmonic generation of 2D KNbO3 with laser vertically incident on the sample. However, a strong third harmonic generation is observed. The effective third-order susceptibility of 2D KNbO3 with the order of ∼10−19 m2 V−2 is estimated by comparing it with the χeff(3) of graphene. The robust power tolerance of 2D KNbO3 endows it great potential in the application of high-power third harmonic generation 2D devices.
{"title":"Third harmonic generation in monoclinic 2D KNbO3 with high power endurance","authors":"Fei Zhou, Yang Li, Haizeng Song, Xianhua Wei, Bo Dai","doi":"10.1116/5.0205350","DOIUrl":"https://doi.org/10.1116/5.0205350","url":null,"abstract":"Two-dimensional (2D) KNbO3 is prepared by topotactic transition from 2D KNbO2 at 530 °C in air, which has a single spontaneous polarization (Ps) direction along the [101¯]pc zone axis. The strong Ps anisotropy leads to a negligible second harmonic generation of 2D KNbO3 with laser vertically incident on the sample. However, a strong third harmonic generation is observed. The effective third-order susceptibility of 2D KNbO3 with the order of ∼10−19 m2 V−2 is estimated by comparing it with the χeff(3) of graphene. The robust power tolerance of 2D KNbO3 endows it great potential in the application of high-power third harmonic generation 2D devices.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiang Chen, Mingxu Su, Dan Liang, Qiong Zhou, Biao Huang, E. Zhang
In order to improve the corrosion resistance and conductivity of 316L stainless steel bipolar plates used for proton exchange membrane fuel cells, three Cr-containing nitride coatings were deposited on 316L stainless steel by multiarc ion plating. First, the microstructure, composition, and contact angle of the three coatings were systematically investigated. Then, electrochemical impedance spectroscopy, potentiodynamic polarization, potentiostatic polarization (PSP), and interfacial contact resistance (ICR) of the three coatings were also fully examined. The results revealed that CrN coating has the highest contact angle of 98.26°, indicating its superior hydrophobicity. Additionally, CrN coating performed the best corrosion resistance with the highest corrosion potential of 0.31 V, the lowest corrosion current density of 2.28 × 10−7 A cm−2, and the largest resistance. Furthermore, CrN coating showed the lowest current density during PSP tests and the smallest ICR value after corrosion. The superior corrosion resistance of CrN coating is mainly attributed to its decreased pore density caused by vacancylike defects and its uniform structure. This article provided evidence for the potential application of CrN coating to bipolar plates.
{"title":"Corrosion resistance and conductivity of CrN, CrAlN, and CrTiN coatings applied to bipolar plates for proton exchange membrane fuel cells","authors":"Qiang Chen, Mingxu Su, Dan Liang, Qiong Zhou, Biao Huang, E. Zhang","doi":"10.1116/6.0003601","DOIUrl":"https://doi.org/10.1116/6.0003601","url":null,"abstract":"In order to improve the corrosion resistance and conductivity of 316L stainless steel bipolar plates used for proton exchange membrane fuel cells, three Cr-containing nitride coatings were deposited on 316L stainless steel by multiarc ion plating. First, the microstructure, composition, and contact angle of the three coatings were systematically investigated. Then, electrochemical impedance spectroscopy, potentiodynamic polarization, potentiostatic polarization (PSP), and interfacial contact resistance (ICR) of the three coatings were also fully examined. The results revealed that CrN coating has the highest contact angle of 98.26°, indicating its superior hydrophobicity. Additionally, CrN coating performed the best corrosion resistance with the highest corrosion potential of 0.31 V, the lowest corrosion current density of 2.28 × 10−7 A cm−2, and the largest resistance. Furthermore, CrN coating showed the lowest current density during PSP tests and the smallest ICR value after corrosion. The superior corrosion resistance of CrN coating is mainly attributed to its decreased pore density caused by vacancylike defects and its uniform structure. This article provided evidence for the potential application of CrN coating to bipolar plates.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141105191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
FeCoNi high-entropy alloy (HEA) is widely used in the aerospace and chemical industry. However, the strength and corrosion resistance of the alloy still need to be improved. In this paper, FeCoNiAl0.2Yx (x = 0, 0.05, 0.1, 0.2, and 0.3 in mole ratio) high entropy alloys with different contents of rare earth (RE) element yttrium (Y) were prepared by the vacuum arc melting method, and then the alloys were subjected to annealing treatment at 800 °C/2h. The microstructure, hardness, magnetism, and corrosion performance of FeCoNiAl0.2Yx HEAs in the annealed state with different contents of element Y were analyzed. The results show that the annealed FeCoNiAl0.2Yx HEAs without the addition of element Y and after the addition of element Y both were composed of a face-centered cubic phase. The alloy showed a dendritic structure inside. The element Y was solidly dissolved in the alloys to refine the microstructure of the alloys, and the dendrites were gradually refined with the addition of Y. The Y element caused the phenomenon of lattice distortion inside the alloys, which led to the increase in the alloys’ hardness. The alloy with x = 0.2 showed the greatest exchange of magnetic atoms and the alloy with x = 0.05 showed the lowest coercivity. The alloy with x = 0.1 showed the lowest self-corrosion current density, the broadest passivation zone, the densest dendrites, the smallest grain spacing, and the weakest tendency for intergranular corrosion. The present study shows that the introduction of element Y improves the microstructural morphology, hardness, magnetism, and corrosion properties of FeCoNiAl0.2Yx HEAs in the annealed state.
铁钴镍高熵合金（HEA）广泛应用于航空航天和化学工业。然而，该合金的强度和耐腐蚀性仍有待提高。本文采用真空电弧熔炼法制备了不同稀土元素钇（Y）含量的 FeCoNiAl0.2Yx（x = 0、0.05、0.1、0.2 和 0.3，摩尔比）高熵合金，然后将合金在 800 °C/2h 下进行退火处理。分析了不同钇元素含量的退火态 FeCoNiAl0.2Yx HEA 的微观结构、硬度、磁性和腐蚀性能。结果表明，未添加 Y 元素和添加 Y 元素后退火的 FeCoNiAl0.2Yx HEA 均由面心立方相组成。合金内部呈现树枝状结构。为了细化合金的微观结构，在合金中固溶了 Y 元素，树枝状结构随着 Y 元素的加入而逐渐细化。x = 0.2 的合金显示出最大的磁性原子交换，而 x = 0.05 的合金显示出最低的矫顽力。x = 0.1 的合金显示出最低的自腐蚀电流密度、最宽的钝化区、最密集的枝晶、最小的晶粒间距和最弱的晶间腐蚀倾向。本研究表明，元素 Y 的引入改善了退火状态下 FeCoNiAl0.2Yx HEA 的微观结构形态、硬度、磁性和腐蚀特性。
{"title":"Effect of rare earth element Y content on microstructure, magnetic properties, and electrochemical properties of the as-annealed FeCoNiAl0.2Yx high-entropy alloys","authors":"Shaojie Cui, Sheng Lei, Yun Li, Junpeng Zhang, Shanshan Hu, Zhengwei Xue","doi":"10.1116/6.0003597","DOIUrl":"https://doi.org/10.1116/6.0003597","url":null,"abstract":"FeCoNi high-entropy alloy (HEA) is widely used in the aerospace and chemical industry. However, the strength and corrosion resistance of the alloy still need to be improved. In this paper, FeCoNiAl0.2Yx (x = 0, 0.05, 0.1, 0.2, and 0.3 in mole ratio) high entropy alloys with different contents of rare earth (RE) element yttrium (Y) were prepared by the vacuum arc melting method, and then the alloys were subjected to annealing treatment at 800 °C/2h. The microstructure, hardness, magnetism, and corrosion performance of FeCoNiAl0.2Yx HEAs in the annealed state with different contents of element Y were analyzed. The results show that the annealed FeCoNiAl0.2Yx HEAs without the addition of element Y and after the addition of element Y both were composed of a face-centered cubic phase. The alloy showed a dendritic structure inside. The element Y was solidly dissolved in the alloys to refine the microstructure of the alloys, and the dendrites were gradually refined with the addition of Y. The Y element caused the phenomenon of lattice distortion inside the alloys, which led to the increase in the alloys’ hardness. The alloy with x = 0.2 showed the greatest exchange of magnetic atoms and the alloy with x = 0.05 showed the lowest coercivity. The alloy with x = 0.1 showed the lowest self-corrosion current density, the broadest passivation zone, the densest dendrites, the smallest grain spacing, and the weakest tendency for intergranular corrosion. The present study shows that the introduction of element Y improves the microstructural morphology, hardness, magnetism, and corrosion properties of FeCoNiAl0.2Yx HEAs in the annealed state.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Naga Prathibha Jasti, S. Tirosh, Ansuman Halder, Eti Teblum, David Cahen
We report continuous wave laser-assisted evaporation (CLE), a thin film deposition technique that yields phase-pure and stoichiometric thin films of halide perovskites (HaPs) from stoichiometric HaP targets. We use methylammonium lead bromide (MAPbBr3) to demonstrate the ability to grow with CLE well-oriented and smooth thin films on various substrates. Further, we show the broader applicability of CLE by preparing films of several other 3D HaP compounds, viz., methylammonium lead iodide, formamidinium lead bromide, and a 2D one, butylammonium lead iodide. CLE is a single-source, solvent-free, room-temperature process that needs only roughing pump vacuum; it allows the deposition of hybrid organic-inorganic compound films without needing post-thermal treatment or an additional organic precursor source to yield the intended product. The resulting films are polycrystalline and highly oriented. All these features, and the fact that one stoichiometric source serves as the target, make for an attractive, potentially scalable dry deposition approach.
{"title":"Continuous wave laser-assisted evaporation of halide perovskite thin films from a single stoichiometric source","authors":"Naga Prathibha Jasti, S. Tirosh, Ansuman Halder, Eti Teblum, David Cahen","doi":"10.1116/6.0003607","DOIUrl":"https://doi.org/10.1116/6.0003607","url":null,"abstract":"We report continuous wave laser-assisted evaporation (CLE), a thin film deposition technique that yields phase-pure and stoichiometric thin films of halide perovskites (HaPs) from stoichiometric HaP targets. We use methylammonium lead bromide (MAPbBr3) to demonstrate the ability to grow with CLE well-oriented and smooth thin films on various substrates. Further, we show the broader applicability of CLE by preparing films of several other 3D HaP compounds, viz., methylammonium lead iodide, formamidinium lead bromide, and a 2D one, butylammonium lead iodide. CLE is a single-source, solvent-free, room-temperature process that needs only roughing pump vacuum; it allows the deposition of hybrid organic-inorganic compound films without needing post-thermal treatment or an additional organic precursor source to yield the intended product. The resulting films are polycrystalline and highly oriented. All these features, and the fact that one stoichiometric source serves as the target, make for an attractive, potentially scalable dry deposition approach.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141109713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gengyu Wang, Wenbo Luo, Dailei Zhu, Yuedong Wang, Y. Shuai, Chuangui Wu, W. Zhang
The defects distribution of ion-implanted SiC is a key to understanding changes in the electronic, optical, and mechanical properties of SiC devices. However, accessing the defect distribution within the sample primarily relies on simulation, yet a number of factors remain unaccounted for in the simulation results, ultimately resulting in numerous inaccuracies. To address this issue, a defect distribution investigation method based on the combination of argon ion etching and deep-ultraviolet (DUV) Raman spectroscopy has been established. The defects at different depths were exposed to the surface by etching, and the crystal quality of the surface layer was assessed using Raman spectra with a 266 nm DUV laser. The spectra for the H+ implanted 4H-SiC showed that the full width at half maximum of the transverse optical mode at 781 cm−1 and the longitudinal optical mode at 965 cm−1 exhibited an increasing and then decreasing trend, approximate to a Gaussian distribution. These results were confirmed with the transmission electron microscopy cross-sectional image and SRIM-2013 simulation. The establishment of this analytical investigation method can be widely applied to other semiconductor materials, without the need for electrodes and sample contamination.
{"title":"Lattice defects distribution of H+ implanted 4H-SiC investigated by deep-ultraviolet Raman spectroscopy","authors":"Gengyu Wang, Wenbo Luo, Dailei Zhu, Yuedong Wang, Y. Shuai, Chuangui Wu, W. Zhang","doi":"10.1116/6.0003643","DOIUrl":"https://doi.org/10.1116/6.0003643","url":null,"abstract":"The defects distribution of ion-implanted SiC is a key to understanding changes in the electronic, optical, and mechanical properties of SiC devices. However, accessing the defect distribution within the sample primarily relies on simulation, yet a number of factors remain unaccounted for in the simulation results, ultimately resulting in numerous inaccuracies. To address this issue, a defect distribution investigation method based on the combination of argon ion etching and deep-ultraviolet (DUV) Raman spectroscopy has been established. The defects at different depths were exposed to the surface by etching, and the crystal quality of the surface layer was assessed using Raman spectra with a 266 nm DUV laser. The spectra for the H+ implanted 4H-SiC showed that the full width at half maximum of the transverse optical mode at 781 cm−1 and the longitudinal optical mode at 965 cm−1 exhibited an increasing and then decreasing trend, approximate to a Gaussian distribution. These results were confirmed with the transmission electron microscopy cross-sectional image and SRIM-2013 simulation. The establishment of this analytical investigation method can be widely applied to other semiconductor materials, without the need for electrodes and sample contamination.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141109974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The interface structure holds paramount significance in enhancing the thermal conductivity (TC) of diamond/Cu composites, positioning them as a promising candidate for thermal management applications. Diamond/Cu composites (55% volume fraction) with three distinct interfacial carbides were fabricated via sintering at 950 °C using Cu and diamond powder coated with Ti, Cr, and W. During the sintering process, interfacial layers of TiC, Cr3C2, and W2C carbides formed at the composite interfaces. The findings reveal that the interfacial bonding strength among these three composites adheres to the following hierarchy: Ti-D/Cu exceeds Cr-D/Cu, which surpasses W-D/Cu. This hierarchy stems from the varying degrees of carbide coating integrity attained at 950 °C. Furthermore, the coating morphology differs on the diamond-{100} and -{111} crystal planes. Notably, among the interfacial carbides, TiC coating exhibits the most compact and contiguous structure postsintering. Consequently, Ti-D/Cu composites boast the highest density, reaching 95.49%, along with a remarkable TC of 317.66 W/mK. A comparative analysis of the fracture morphology of these composites reveals that Ti-D/Cu, characterized by the most robust interfacial bonding, exhibits a intransgranular fracture mechanism. This study offers profound insights and theoretical implications for the interface design of diamond/Cu composites, paving the way for their effective utilization in heat dissipation materials.
{"title":"Effects of different element coatings on the interface characteristics and thermal conductivity of vacuum-sintered diamond/Cu composites","authors":"Q. W. Zhou, L. Bolzoni, F. Yang","doi":"10.1116/6.0003600","DOIUrl":"https://doi.org/10.1116/6.0003600","url":null,"abstract":"The interface structure holds paramount significance in enhancing the thermal conductivity (TC) of diamond/Cu composites, positioning them as a promising candidate for thermal management applications. Diamond/Cu composites (55% volume fraction) with three distinct interfacial carbides were fabricated via sintering at 950 °C using Cu and diamond powder coated with Ti, Cr, and W. During the sintering process, interfacial layers of TiC, Cr3C2, and W2C carbides formed at the composite interfaces. The findings reveal that the interfacial bonding strength among these three composites adheres to the following hierarchy: Ti-D/Cu exceeds Cr-D/Cu, which surpasses W-D/Cu. This hierarchy stems from the varying degrees of carbide coating integrity attained at 950 °C. Furthermore, the coating morphology differs on the diamond-{100} and -{111} crystal planes. Notably, among the interfacial carbides, TiC coating exhibits the most compact and contiguous structure postsintering. Consequently, Ti-D/Cu composites boast the highest density, reaching 95.49%, along with a remarkable TC of 317.66 W/mK. A comparative analysis of the fracture morphology of these composites reveals that Ti-D/Cu, characterized by the most robust interfacial bonding, exhibits a intransgranular fracture mechanism. This study offers profound insights and theoretical implications for the interface design of diamond/Cu composites, paving the way for their effective utilization in heat dissipation materials.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141123410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Stramaglia, G. Panchal, L. Tovaglieri, C. Lichtensteiger, F. Nolting, C. Vaz
We report the direct imaging of the magnetic response of a 4.8 nm La0.9Ba0.1MnO3 film to the voltage applied across a 5 nm BaTiO3 film in a BaTiO3/La0.9Ba0.1MnO3 multiferroic heterostructure using x-ray photoemission electron microscopy (XPEEM). Specifically, we have written square ferroelectric domains on the BaTiO3 layer with an atomic force microscope in contact mode and imaged the corresponding magnetic contrast through the x-ray circular dichroic effect at the Mn L-edge with high spatial lateral resolution using XPEEM. We find a sudden decrease in the magnetic contrast for positive writing voltages above +6 V associated with the switching of the ferroelectric polarization of the BaTiO3, consistent with the presence of a magnetoelectric effect through changes in the hole carrier density at the BaTiO3/La0.9Ba0.1MnO3 interface. Temperature-dependent measurements show a decrease in the Curie temperature and magnetic moment in the areas where a positive voltage above +6 V was applied, corresponding to the hole depletion state and suggesting the onset of a spin-canted state of bulk La0.9Ba0.1MnO3. Our results are the first direct imaging of magnetoelectric coupling in such multiferroic heterostructure.
我们报告了在 BaTiO3/La0.9Ba0.1MnO3 多铁电体异质结构中，利用 x 射线光发射电子显微镜 (XPEEM) 直接成像 4.8 nm La0.9Ba0.1MnO3 薄膜对施加在 5 nm BaTiO3 薄膜上的电压的磁响应。具体来说，我们用原子力显微镜在接触模式下在 BaTiO3 层上写入了方形铁电畴，并通过 Mn L 边的 X 射线圆二色效应，用 XPEEM 以高空间横向分辨率对相应的磁对比进行了成像。我们发现，当正写入电压超过 +6 V 时，磁对比度会突然下降，这与 BaTiO3 的铁电极化切换有关，这与通过改变 BaTiO3/La0.9Ba0.1MnO3 界面的空穴载流子密度而产生的磁电效应是一致的。随温度变化的测量结果表明，在施加 +6 V 以上正电压的区域，居里温度和磁矩都有所下降，这与空穴耗尽态相对应，并表明块体 La0.9Ba0.1MnO3 开始进入自旋倾斜态。我们的研究结果是对此类多铁性异质结构中磁电耦合的首次直接成像。
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Yanxia Wu, Jiawei Qi, Ke Li, Xiaoyan Zhou, Shengwang Yu, Caili Zhang, Ying Liu
Ni was selected as a transition layer and sublayer in the diamondlike carbon-based multilayered film with varied bilayer periods (from 228 to 970 nm) prepared by magnetron sputtering. The reaction between Ni- and C-containing particles was discussed, and the influences of bilayer periods on the structure and morphology, accompanied with the frictional behaviors at different loading forces (2 and 5 N), as well as the field emission properties were investigated. The results showed that Ni grew in the (111) plane, and there was no Ni–C bond or graphene formed in the film because of the relatively lower energy during deposition. Moreover, the content of sp2C in the film, the hardness, and the field emission performance exhibited an initial increase followed by a subsequent decrease with increasing bilayer periods. However, the frictional coefficient decreased owing to more graphitization with an increase of the applied load. Particularly noteworthy was that the film possessed a bilayer period of 710 nm, displayed a compact structure with a smaller grain size, and showed reduced sp2C content in the role of Ni. This resulted in sustained lower surface roughness, heightened hardness, decreased coefficient of friction, and a smaller opening electric field.
{"title":"Preparation and tribological properties of Ni/DLC multilayer film","authors":"Yanxia Wu, Jiawei Qi, Ke Li, Xiaoyan Zhou, Shengwang Yu, Caili Zhang, Ying Liu","doi":"10.1116/6.0003431","DOIUrl":"https://doi.org/10.1116/6.0003431","url":null,"abstract":"Ni was selected as a transition layer and sublayer in the diamondlike carbon-based multilayered film with varied bilayer periods (from 228 to 970 nm) prepared by magnetron sputtering. The reaction between Ni- and C-containing particles was discussed, and the influences of bilayer periods on the structure and morphology, accompanied with the frictional behaviors at different loading forces (2 and 5 N), as well as the field emission properties were investigated. The results showed that Ni grew in the (111) plane, and there was no Ni–C bond or graphene formed in the film because of the relatively lower energy during deposition. Moreover, the content of sp2C in the film, the hardness, and the field emission performance exhibited an initial increase followed by a subsequent decrease with increasing bilayer periods. However, the frictional coefficient decreased owing to more graphitization with an increase of the applied load. Particularly noteworthy was that the film possessed a bilayer period of 710 nm, displayed a compact structure with a smaller grain size, and showed reduced sp2C content in the role of Ni. This resulted in sustained lower surface roughness, heightened hardness, decreased coefficient of friction, and a smaller opening electric field.","PeriodicalId":509398,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139962754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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