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Graphene-based membranes for organic solvent nanofiltration

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Science China Materials 2018年第3期61卷 429-431页

作者： Ruirui Hu Hongwei Zhu state key lab of new ceramics and fine processing School of Materials Science and Engineering Tsinghua University

Different from the conventional polymeric separation membranes having a wide flexible-pore size distribution,layered graphene-based films with interconnected nanochannels provide narrowly well-defined nanopore-size di... 详细信息

关键词： CGO OSN

Opaque Gd_(2)Zr_(2)O_(7)/GdMnO_(3) thermal barrier materials for thermal radiation shielding:The effect of polaron excitation

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Journal of Materials Science & Technology 2022年第5期100卷 67-74页

作者： Muzhang Huang Jia Liang Peng Zhang Yi Li Yi Han Zesheng Yang Wei Pan Chunlei Wan state key lab of new ceramics and fine processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Opaque thermal barrier materials play a pivotal role in thermal radiation shielding of turbine blades,since the intensity of thermal radiation rapidly increases with the increase of operating temperature of gas turbines and has become a new and major concern for the durability of metallic *** conventional thermal barrier coating(TBC)materials such as YSZ and Gd_(2)Zr_(2)O_(7),however,are almost translucent to thermal radiation and are unable to protect the blades at such harsh *** searching for new thermal barrier materials is significant,it is still a challenge to make the current TBC materials opaque without significantly modifying the composition or other physical *** cope with this challenge,GdMnO_(3) is incorporated as an absorptive second phase into Gd_(2)Zr_(2)O_(7) in this work,which is originally translucent(absorption coefficient 10^(1)-10^(2) m^(-1))in the near-infrared ***,with less than 5 wt.%GdMnO_(3),the Gd_(2)Zr_(2)O_(7)/GdMnO_(3) becomes opaque to thermal radiation and successfully refrains the rise of thermal conductivity at high ***,the lattice thermal conductivity and mechanical properties are almost *** small polaron mechanism is confirmed for GdMnO_(3),leading to a high absorption coefficient(>10^(6) m^(-1))for near-infrared *** understand the underling mechanism,a theoretical model is built to estimate the absorption coefficient of the Gd_(2)Zr_(2)O_(7)/GdMnO_(3) composites(>10^(4) m^(-1)).This paper proposes a powerful strategy to design thermal-radiation-shielding TBCs through incorporating minor second-phase particles with high-absorption mechanism,such as polaron excitation.

关键词： Thermal barrier coatings Thermal radiation Radiative heat transfer Emissivity Small polaron

Tunnel elasticity enhancement effect of 3D submicron ceramics(A_(l)2O_(3),TiO_(2),ZrO_(2)) fiber on polydimethylsiloxane (PDMS)

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Journal of Advanced ceramics 2021年第3期10卷 502-508页

作者： Yuxiu HAO Junwei XIE Bingqing XU Bingkun HU Yunpeng ZHENG Yang SHEN state key lab of new ceramics and fine processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Some polymers are flexible,foldable,and ***-functional composite is fabricated by adding inorganic fillers with functional *** to date,compared with the polymer matrix,the composite prepared by polymer-inorganic fillers has lower flexibility,higher brittleness,and higher modulus of *** this paper,three-dimensional (3D) net-shaped submicron α-Al_(2)O_(3),orthorhombic ZrO_(2),and rutile TiO_(2) fiber were fabricated by solution blowing spinning on a large *** the contrary,the elastic modulus (E) of the composite prepared by this 3D ceramic fiber was greatly reduced,and the flexibility of the composite was higher than that of the polymer *** the strain was 75%,the E of the 3D net-shaped Al_(2)O_(3) fiber-polydimethylsiloxane(PDMS) composite was 20% lower than that of *** the strain was 78%,the E of the 3D net-shaped TiO_(2) fiber-PDMS and 3D net-shaped ZrO_(2) fiber-PDMS composites decreased by 20% and 25%,*** abnormal effect,namely the tunnel elastic enhancement effect,has great practical *** all-solid-state lithium-ion batteries,the composite inhibits lithium dendrite growth and the 3D inorganic network contributes to lithium ion *** is possible to promote the industrial production of low-cost and large-scale flexible solid-state lithium-ion batteries and it can enhance the energy storage density of energy storage *** novel idea also has bright prospects in flexible electronic materials.

关键词： ceramic fiber tunnel elasticity enhancement effect solution blowing spinning

Crystalline boron nitride nanosheets by sonication-assisted hydrothermal exfoliation

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Journal of Advanced ceramics 2019年第1期8卷 72-78页

作者： Zhaobo TIAN Kexin CHEN Siyuan SUN Jie ZHANG Wei CUI Zhipeng XIE Guanghua LIU state key laboratory of new ceramics and fine processing School of Materials Science and Engineering Tsinghua University

A simple method to prepare two-dimensional hexagonal boron nitride(h-BN) scalably is essential for practical applications. Despite intense research in this area, high-yield production of two-dimensional h-BN with large size and high crystallinity is still a key challenge. In the present work, we propose a simple exfoliation process for boron nitride nanosheets(BNNSs) with high crystallinity by sonication-assisted hydrothermal method, via the synergistic effect of the high pressure, and cavitation of the sonication. Compared with the method only by sonication, the sonication-assisted hydrothermal method can get the fewer-layer BNNSs with high ***, it can reach higher yield of nearly 1.68%, as the hydrothermal method with the yield of only 0.12%. The simple sonication-assisted hydrothermal method has potential applications in exfoliating other layered materials, thus opening new ways to produce other layered materials in high yield and high crystallinity.

关键词： boron nitride nanosheet (BNNS) high crystallinity sonication-assisted hydrothermal method

Ferroelectric and dielectric properties of La/Mn co-doped Bi_4Ti_3O_12 ceramics

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Chinese Physics B 2010年第3期19卷 539-545页

作者：吴云翼王晓慧李龙土 state key laboratory of new ceramics and fine processing Department of Materials Science and EngineeringTsinghua University

La/Mn co-doped Bi4Ti3O12 ceramics, Bi3.25La0.75Ti3-xMnxO12 （x = 0.02, 0.04, 0.06, 0.08）, were prepared by the solid-state reaction method. The influence of manganese substitution for the titanium part in Bi3.25La0.75Ti3O12 on the sintering behaviour, microstructure, Raman spectra and electrical properties was investigated. The experimental results show that the phase composition of all samples with and without manganese doping, sintered at 1000 ℃, consists of a single phase with a bismuth-layered structure belonging to the crystalline phase Bi4Ti3O12. There is no evidence of any impurity phase, but a small change in crystallographic orientation is observed. The Curie temperature of Bi3.25La0.75Ti3-xMnxO12 ceramics is steadily shifted to lower temperature with increasing Mn-doping content. Moreover, the remnant polarisation （Pr） of Bi3.25La0.75Ti3- xMnxO12 samples increases with Mn-doping content, and the Bi3.25La0.75Ti2.92Mn0.08O12 sample exhibits the largest Pr of 16.6 μC/cm^2.

关键词： bismuth titanate ceramics doping ferroelectric

Controllable fabrication and multifunctional applications of graphene/ceramic composites

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Journal of Advanced ceramics 2020年第3期9卷 271-291页

作者： Yujia HUANG Chunlei WAN state key lab of new ceramics and fine processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Graphene with excellent comprehensive properties has been considered as a promising filler to reinforce *** numerous studies have been devoted to the improvement of mechanical and electrical properties,incorporating graphene to ceramics also offers new opportunities for endowing ceramics with *** this review,the recent development of graphene/ceramic bulk composites is summarized with the focus on the construction of well-designed architecture and the realization of multifunctional *** processing technologies of the composites are systematically summarized towards homogeneous dispersion and even ordered orientation of graphene sheets in the ceramic *** improvement of composites in mechanical,electrical,electromagnetic,and thermal performances is *** novel multifunctional applications brought by smart integration of graphene in ceramics are also addressed,including microwave absorption,electromagnetic interference shielding,ballistic armors,self-monitor damage sensors,and energy storage and conversion.

关键词： graphene/ceramic composites synthesis mechanical property electromagnetic properties thermal properties multifunction

Versatile memristor implemented in van der Waals CuInP_(2)S_(6)

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Nano Research 2023年第7期16卷 10191-10197页

作者： Yiqun Liu Yonghuang Wu Bolun Wang Hetian Chen Di Yi Kai Liu Ce-Wen Nan Jing Ma state key lab of new ceramics and fine processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Memristors are playing an increasingly important role in developing in-memory *** memristors which offer both volatile and non-volatile performances can be employed as both memories and selectors,displaying unique advantages for developing novel electronic ***,the remarkable multifunctional memristor with switchable operating modes between volatile and non-volatile by regulating compliance currents is implemented in Ag/CIPS/Au(CIPS:CuInP_(2)S_(6))***-like volatile memristor performances with the rectification ratio of 10^(3) and an endurance of 500 switching cycles were ***,significant non-volatile memory performances with on/off ratio of 10^(3)and retention up to 10^(4)s were also developed,which enables it to be utilized as selectors and memories ***,such versatile memristor can emulate the short-term plasticity(STP)and long-term plasticity(LTP)of artificial synapse,demonstrating its advantages in neuromorphic computing applications.

关键词： CuInP_(2)S_(6)(CIPS) versatile memristor conductive filament synaptic plasticity

Grain size refinement of additive manufactured Ce-TZP ceramics by coupled two-step pre-sintering and HIP

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Journal of Advanced ceramics 2024年第5期13卷 621-629页

作者： Ruoshi Zhao Hongbing Yang Xintong Liu Hezhen Li Chang-An Wang Jing Ma Yanhao Dong state key lab of new ceramics and fine processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Ceria-stabilized tetragonal zirconia polycrystal(Ce-TZP)has exceptional fracture toughness and flaw tolerance due to facile t‒m phase transformation ***,its wider-range applications are limited by its relatively low strength due to its large grain size and low transformation stress,which results in yield-like ***,we combined additive manufacturing(AM),pressureless two-step sintering,and hot isostatic pressing(HIP),and addressed the challenging grain size refinement problem in *** successfully produced dense ultrafine-grained Ce-TZP ceramics with an average grain size below 500 nm,a three-point bending strength above 800 MPa,and a single-edge-notch-beam fracture toughness in the range of 11‒12 MPa·m^(1/2).The critical roles of processing design,mixed Ce valences,and ***-stabilization of tetragonal polymorphs were *** work offers insights and strategies for the future development of stronger and tougher Ce-TZP ceramics that can compete with tetragonal yttria-stabilized zirconia in various applications,including additive manufacturing.

关键词： zirconia additive manufacturing(AM) two-step sintering hot isostatic pressing(HIP) grain size refinement

Defect characterization and magnetic properties in un-doped ZnO thin film annealed in a strong magnetic field

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Chinese Physics B 2014年第12期23卷 458-463页

作者：宁帅战鹏王炜鹏李正操张政军 state key laboratory of new ceramics and fine processing School of Materials Science and Engineering Tsinghua University

Highly c-axis oriented un-doped zinc oxide（Zn O） thin films, each with a thickness of ～ 100 nm, are deposited on Si（001） substrates by pulsed electron beam deposition at a temperature of ～ 320℃, followed by annealing at 650℃ in argon in a strong magnetic field. X-ray photoelectron spectroscopy（XPS）, positron annihilation analysis（PAS）, and electron paramagnetic resonance（EPR） characterizations suggest that the major defects generated in these Zn O films are oxygen vacancies. Photoluminescence（PL） and magnetic property measurements indicate that the room-temperature ferromagnetism in the un-doped Zn O film originates from the singly ionized oxygen vacancies whose number depends on the strength of the magnetic field applied in the thermal annealing process. The effects of the magnetic field on the defect generation in the Zn O films are also discussed.

关键词： magnetic semiconductors magnetic annealing defects zinc oxides