Mechanical and dielectric properties of reduced graphene oxide nanosheets/alumina composite ceramics

Zhou, Liang; Qiu, Jieyou; Wang, Xingang; Wang, Hongbo; Wang, Zhenjun; Fang, Daqing; Li, Zhuo

doi:10.1016/j.ceramint.2020.04.293

Cited by 20 publications

(4 citation statements)

References 33 publications

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“…The rapid development of wireless communication with the broadband network has significantly increased the demand for microwave dielectric ceramics of excellent dielectric behaviors (e.g., suitable relative permittivity, high quality factor, and low-temperature drift of resonance frequency [1][2][3]) together with high J u s t A c c e p t e d mechanical properties (e.g., elastic modulus, hardness, and fracture toughness [4][5][6][7]), since excellent mechanical properties (e.g., high cracking resistance [8][9][10][11] and penetration resistance [12,13]) can ensure high structural stability, high reliability and long-term service life of dielectric ceramics, and have drawn extensive attention in the field of dielectric ceramics [4][5][6]14]. Values of Meyer and Knoop hardness of dielectric ceramic (Ba0.9Ca0.1)0.9(Na0.5Bi0.5)0.1TiO3 were found to be almost the same, and both increased with increasing sintering temperature [15].…”

Section: Introductionmentioning

confidence: 99%

Micromechanical characterization of microwave dielectric ceramic BaO–Sm₂O₃–5TiO₂by indentation and scratch methods

Liu¹,

Xu²

2023

Journal of Advanced Ceramics

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Mechanical characterization of dielectric ceramics, which have drawn extensive attention in wireless communication, remains challenging. Micromechanical properties with microstructures of dielectric ceramic BaO-Sm2O3-5TiO2 (BST) were assessed by nanoindentation, microhardness, and microscratch tests under different indenters, along with X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. Accurate determination of elastic modulus (i.e., 260 GPa) and indentation hardness (i.e., J u s t A c c e p t e d 16.2 GPa) of brittle BST ceramic by instrumented indentation technique requires low loads with little indentation-induced damage. Elastic modulus and indentation hardness were analyzed by different methodologies such as energybased and displacement-based approaches, and elastic recovery of Knoop imprint. Consistent values (about 3.1 MPa·m 1/2 ) of fracture toughness of BST ceramic were obtained by different methods such as Vickers indenter-induced cracking method, energy-based nanoindentation approaches, and linear elastic fracture mechanics-based scratch approach with a spherical indenter, demonstrating successful applications of indentation and scratch methods in characterizing fracture properties of brittle solids. The deterioration of elastic modulus or indentation hardness with the increase in indentation load is caused by indentation-induced damage, and can be used to determine fracture toughness of material by energy-based nanoindentation approaches, and the critical void volume fraction is 0.27 (or 0.18) if elastic modulus (or indentation hardness) of the brittle BST ceramic is used. The fracture work at the critical load corresponding to the initial decrease in elastic modulus or indentation hardness can also be used to assess fracture toughness of brittle solids, opening new venues of application of nanoindentation test as a means to characterize fracture toughness of brittle ceramics.

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Section: Introductionmentioning

confidence: 99%

Micromechanical characterization of microwave dielectric ceramic BaO–Sm₂O₃–5TiO₂by indentation and scratch methods

Liu¹,

Xu²

2023

Journal of Advanced Ceramics

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“…Inversely, the presence of graphene in polythiocarbonate decreased its dielectric loss . Despite their outstanding performance when tested in their flexibility range, pure graphene or graphene oxide still shows limited buckling ability when subjected to narrow curvature or high mechanical deformation. , …”

Section: Introductionmentioning

confidence: 99%

“…23 Despite their outstanding performance when tested in their flexibility range, pure graphene or graphene oxide still shows limited buckling ability when subjected to narrow curvature or high mechanical deformation. 24,25 Nanofiber composites can be used as a flexible candidate material for applications as electrode capacitors. Graphene oxide can be loaded into the nanofiber composites.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Properties and Flexibility of Polyacrylonitrile/Graphene Oxide Composite Nanofibers

et al. 2022

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Energy storage and modern electronics industries are in essential need of high dielectric and highly flexible materials. In this study, polyacrylonitrile and reduced graphene oxide (PAN/GO) were prepared by electrospinning. The composite morphology produced a homogeneous, smooth, and flexible surface with high tensile strength and durability. The diameter of the fibers in the composite mats ranged from 232 to 592 nm. The X-ray diffraction pattern recording displayed a sharp peak characteristic centered between 20 and 30° angles with a maximum degree of crystallinity of 86.23%. The evaluation of the Fourier-transform infrared spectrum indicated the interaction between GO and PAN through hydrogen bonds. The differential scanning calorimetry measurements confirmed that GO acted as a nucleating agent that improves the thermal stability of the composite. The dielectric properties exhibited the relative permittivity of the composite of 86.4 with a dielectric loss (tan δ) of 4.97 at 10 2 Hz, and the maximum conductivity was achieved at 34.9 × 10 –6 Sm –1 at high frequencies.

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“…Therefore, the protection of electromagnetic pollution caused by electromagnetic waves has been taken into consideration. Different from hard resin-based or ceramic-based composite materials [4][5][6], due to the high elasticity of rubber, conductive rubber composite materials are used as sensors, thermistors, wearable electronic devices and electromagnetic material [7][8][9][10][11][12][13]. At present, in order to improve the microwave absorption of rubber-based composites, some conductive particles, such as carbon black (CB) [14][15][16], single-wall carbon nanotubes [17], multi-wall carbon nanotubes [18], barium titanate (BT) [19], M-type hexagonal ferrites [20], Pb (Mg 1/3 Nb 2/3 ) 0.65 Ti 0.35 O 3 powder [21] and carbonyl iron [22,23] are added alone.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Dielectric Properties of a Flexible Anisotropic Rubber-Based Composite

et al. 2022

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Rubber-based conductive composites are widely used in sensors, wearable electronic devices and electromagnetic fields. In this work, by using the two-roll milling and hot-pressing process, chopped glass fiber (CGF) and graphene (Gr) as additives, and acrtlinitrile-brtadiene rubber (NBR) as the matrix, a series of anisotropic flexible rubber-based composites were prepared. Using this preparation method, both CGF and Gr additives were directly arranged in the material. When the content of CGF was 1 wt.%, the tensile strength in both the T and W directions of the material reached 27 MPa and 28 MPa, respectively. When the content of CGF was fixed at 1 wt.% and Gr was 1.5 wt.% and the elongation at break in both directions reached 328% and 347%. By focusing on the comparison of the dielectric differences in the T and W directions in the X band, it was found that the directional arrangement of the additives led to differences in the dielectric properties.

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Mechanical and dielectric properties of reduced graphene oxide nanosheets/alumina composite ceramics

Cited by 20 publications

References 33 publications

Micromechanical characterization of microwave dielectric ceramic BaO–Sm₂O₃–5TiO₂by indentation and scratch methods

Micromechanical characterization of microwave dielectric ceramic BaO–Sm₂O₃–5TiO₂by indentation and scratch methods

Dielectric Properties and Flexibility of Polyacrylonitrile/Graphene Oxide Composite Nanofibers

Mechanical and Dielectric Properties of a Flexible Anisotropic Rubber-Based Composite

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Mechanical and dielectric properties of reduced graphene oxide nanosheets/alumina composite ceramics

Cited by 20 publications

References 33 publications

Micromechanical characterization of microwave dielectric ceramic BaO–Sm2O3–5TiO2by indentation and scratch methods

Micromechanical characterization of microwave dielectric ceramic BaO–Sm2O3–5TiO2by indentation and scratch methods

Dielectric Properties and Flexibility of Polyacrylonitrile/Graphene Oxide Composite Nanofibers

Mechanical and Dielectric Properties of a Flexible Anisotropic Rubber-Based Composite

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Micromechanical characterization of microwave dielectric ceramic BaO–Sm₂O₃–5TiO₂by indentation and scratch methods

Micromechanical characterization of microwave dielectric ceramic BaO–Sm₂O₃–5TiO₂by indentation and scratch methods