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Co-modulated interface binding energy and electric field distribution of layer-structured PVDF–LDPE dielectric composites with BaTiO3: experiment and multiscale simulations

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Frontiers of Materials Science 2023年第3期17卷 155-167页

作者： Ruitian Bo Chunfeng Wang Yongliang Wang peigang he Zhidong Han School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150040China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory of Engineering Dielectrics and Its Application(Ministry of Education) Harbin University of Science and TechnologyHarbin 150080China

The layer-structured composites were built by the dielectric and insulating layers composed of polyvinylidene fluoride(PVDF)and low-density polyethylene(LDPE)composites containing barium titanate(BT)to modulate the dielectric and energy storage properties of the *** simulations on the interface models for molecular dynamics and the geometric models for finite element analysis were performed together with the experimental characterization of the morphology,dielectric,and energy storage properties of the *** results revealed that polyethylene as an insulating layer played a successful role in modulating dielectric permittivity and breakdown strength while BT particles exerted positive effects in improving the miscibility between the composed layers and redistributing the electric *** strong interface binding energy and the similar dielectric permittivity between the PVDF layer and the BT20/LDPE layer made for the layer-structured composites with a characteristic breakdown strength(Eb)of 188.9 kV·mm^(−1),a discharge energy density(Ud)of 1.42 J·cm^(−3),and a dielectric loss factor(tanδ)of 0.017,which were increased by 94%,141%,and decreased by 54%in comparison with those of the BT20/PVDF composite,respectively.

关键词： dielectric composite layer structure low-density polyethylene polyvinylidene fluoride molecular dynamics simulation finite element analysis

Preparation and anisotropic properties of textured structural ceramics: A review

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Journal of Advanced Ceramics 2019年第3期8卷 289-332页

作者： Zhuo ZHANG Xiaoming DUAN Baofu QIU Zhihua YANG Delong CAI peigang he Dechang JIA Yu ZHOU Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin150001China Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute ofTechnologyHarbin Institute of TechnologyHarbin150001China

Ceramics are usually composed of randomly oriented grains and intergranular phases, so their properties are the statistical average along each direction and show isotropy corresponding to the uniform microstructures. Some methods have been developed to achieve directional grain arrangement and preferred orientation growth during ceramic preparation, and then textured ceramics with anisotropic properties are obtained. Texture microstructures give particular properties to ceramics along specific directions, which can effectively expand their application fields. In this review, typical texturing techniques suitable for ceramic materials, such as hot working, magnetic alignment, and templated grain growth(TGG), are discussed. Several typical textured structural ceramics including α-Al2O3 and related nacre bioinspired ceramics, Si3N4 and SiAlON, h-BN, MB2 matrix ultra-high temperature ceramics, MAX phases and their anisotropic properties are presented.

关键词： texture structural ceramics anisotropic properties strengthening and toughening mechanisms

Effects of Zr and chopped C fiber on microstructure and mechanical properties of SiBCN ceramics

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Science China(Technological Sciences) 2020年第8期63卷 1520-1530页

作者： ZHU QiShuai WANG GaoYuan LIAO XingQi LI DaXin YANG ZhiHua JIA DeChang DUAN XiaoMing he peigang ZHOU Yu Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China Key Laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing Technology Ministry of Industry and Information TechnologyHarbin 150080China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150080China

To further improve the thermal shock resistance and ablation resistance of SiBCN system ceramics targeted much harsh environment,both ultra-high temperature ceramic phases and carbon fibers are expected to be incorporated simultaneously as the ***,tough problems like difficulty in densification as well as degradation of C fibers(Cf)due to interfacial reaction usually cannot be ***,in this study,Zr as well as chopped Cf with BN coating were introduced into SiBCN ceramics by mechanical alloying and after hot-pressing sintering to prepare Cf/SiBCNZr *** structure and phase component development have been characterized in detail by XRD,SEM,TEM and XPS etc.,and mechanical properties,fracture behavior and toughening mechanisms were also ***-B and Zr-O bonds are detected besides Si-C,N-B and N-B-C bonds when pre-alloyed ZrB2 amorphous powder was incorporated into SiBCN system by further mechanical-alloying *** hot-pressing,the ultra-high temperature phases of ZrB2 and ZrN were formed as expected besides the original matrix phases of BN(C)and *** mechanical properties can be obtained for SiBCNZr *** BN coating on carbon fibers successfully avoids the severe fiber degradation and makes it possible for moderating strong interface bonding,which ensuring the debonding,crack deflection,fiber pulling-out and bridging during the *** a result,the Cf/SiBCNZr composites retain good mechanical properties and fractures in a pseudoplastic fracture manner,showing better potential applications in harsh *** of the BN coating on Cf and Zr incorporation by pre-mechanical alloying can be a good route to achieve Cf/SiBCNZr composites with a better balance between thermal shock resistance,ablation resistance and mechanical properties.

关键词： SiBCN ZrB2 ZrN carbon fiber BN coating chemical bond microstructure mechanical properties fracture toughening

3D-printed Lunar regolith simulant-based geopolymer composites with bio-inspired sandwich architectures

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Journal of Advanced Ceramics 2023年第3期12卷 510-525页

作者： Siqi Ma Yuqi Jiang Shuai Fu peigang he Chengyue Sun Xiaoming Duan Dechang Jia Paolo Colombo Yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural–Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Max Planck Institute for Polymer Research Mainz 5512Germany Laboratory for Space Environment and Physical Sciences Harbin Institute of TechnologyHarbin 150001China Department of Industrial Engineering University of PadovaPadova 35122Italy Department of Materials Science and Engineering The Pennsylvania State UniversityPhiladelphia 16802USA

Over time,natural materials have evolved to be lightweight,high-strength,tough,and damage-tolerant due to their unique biological ***,combining biological inspiration and structural design would provide traditional materials with a broader range of performance and ***,the application of an ink-based three-dimensional(3D)printing strategy to the structural design of a Lunar regolith simulant-based geopolymer(HIT-LRS-1 GP)was first reported,and high-precision carbon fiber/quartz sand-reinforced biomimetic patterns inspired by the cellular sandwich structure of plant stems were *** study demonstrated how different cellular sandwich structures can balance the structure–property relationship and how to achieve unprecedented damage tolerance for a geopolymer *** results presented that components based on these biomimetic architectures exhibited stable non-catastrophic fracture characteristics regardless of the compression direction,and each structure possessed effective damage tolerance and anisotropy of mechanical *** results showed that the compressive strengths of honeycomb sandwich patterns,triangular sandwich patterns,wave sandwich patterns,and rectangular sandwich patterns in the Y-axis(Z-axis)direction were 15.6,17.9,11.3,and 20.1 MPa(46.7,26.5,23.8,and 34.4 MPa),respectively,and the maximum fracture strain corresponding to the above four structures could reach 10.2%,6.7%,5.8%,and 5.9%(12.1%,13.7%,13.6%,and 13.9%),respectively.

关键词： Lunar regolith simulant(LRS) three-dimensional(3D)printing geopolymer(GP) in situ resource utilization(ISRU) bio-inspired patterns damage tolerance

Texture and anisotropy of hot-pressed h-BN matrix composite ceramics with in situ formed YAG

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Journal of Advanced Ceramics 2022年第4期11卷 532-544页

作者： Zhuo ZHANG Xiaoming DUAN Zhuo TIAN Yujin WANG Lan WANG Lei CheN Baofu QIU Delong CAI peigang he Dechang JIA Yu ZHOU Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006China

Textured hexagonal boron nitride(h-BN)matrix composite ceramics were prepared by hotpressing using different contents of 3Y_(2)O_(3)–5Al_(2)O_(3)(molar ratio of 3:5)as the sintering *** hot-pressing,the liquid Y_(3)Al_(5)O_(12)(YAG)phase showing good wettability to h-BN grains was in situ formed through the reaction between Y_(2)O_(3) and Al_(2)O_(3),and a coherent relationship between h-BN and YAG was observed with[010]_(h-BN)//[111]_(YAG) and(002)_(h-BN)//(321)_(YAG).In the YAG liquid phase environment formed during hot-pressing,plate-like h-BN grains were rotated under the uniaxial sintering pressure and preferentially oriented with their basal surfaces perpendicular to the sintering pressure direction,forming textured microstructures with the c-axis of h-BN grains oriented parallel to the sintering pressure direction,which give these composite ceramics anisotropy in their mechanical and thermal *** highest texture degree was found in the specimen with 30 wt%YAG,which also possesses the highest anisotropy degree in thermal *** aggregation of YAG phase was observed in the specimen with 40 wt%YAG,which resulted in the buckling of h-BN plates and significantly reduced the texture degree.

关键词： hexagonal boron nitride(h-BN) liquid phase sintering texture anisotropy

Microstructural evolution of h-BN matrix composite ceramics with La-Al-Si-O glass phase during hot-pressed sintering

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Journal of Advanced Ceramics 2021年第3期10卷 493-501页

作者： Baofu QIU Xiaoming DUAN Zhuo ZHANG Chen ZHAO Bo NIU peigang he Delong CAI Lei CheN Zhihua YANG Yujin WANG Dechang JIA Yu ZHOU Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

BN/La-Al-Si-O composite ceramics were fabricated by hot-pressed sintering using hexagonal boron nitride(h-BN),lanthanum oxide(La_(2)O_(3)),aluminia(Al_(2)O_(3)),and amorphous silica(SiO_(2))as the raw *** effects of sintering temperature on microstructural evolution,bulk density,apparent porosity,and mechanical properties of the h-BN composite ceramics were *** results indicated that La-Al-Si-O liquid phase was formed during sintering process,which provided an environment for the growth of h-BN *** increasing sintering temperature,the cristobalite phase precipitation and h-BN grain growth occurred at the same time,which had a significant influence on the densification and mechanical properties of h-BN composite *** best mechanical properties of BN/La-Al-Si-O composite ceramics were obtained under the sintering temperature of 1700℃.The elastic modulus,flexural strength,and fracture toughness were 80.5 GPa,266.4 MPa,and 3.25 MPa·m^(1/2),respectively.

关键词： h-BN matrix composite ceramics La-A1-Si-O glass phase microstructural evolution nanocrystalline precipitation mechanical properties

Microstructural evolution and mechanical properties of in situ nano Ta_(4)HfC_(5) reinforced SiBCN composite ceramics

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Journal of Advanced Ceramics 2020年第6期9卷 739-748页

作者： Bingzhu WANG Daxin LI Zhihua YANG Dechang JIA Jingyi GUAN Hao PENG Delong CAI peigang he Xiaoming DUAN Yu ZHOU Tao ZHANG Chenguang GAO Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Beijing Institute of Control Engineering Beijing 100080China

The in situ nano Ta_(4)HfC_(5) reinforced SiBCN-Ta_(4)HfC_(5) composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing *** microstructural evolution and mechanical properties of the resulting SiBCN-Ta_(4)HfC_(5) were *** the first-step milling of 30 h,the raw materials of TaC and HfC underwent crushing,cold sintering,and short-range interdiffusion to finally obtain the high pure nano Ta_(4)HfC_(5).A hybrid structure of amorphous SiBCN and nano Ta_(4)HfC_(5) was obtained by adopting a second-step *** reactive hot-pressing sintering,amorphous SiBCN has crystallized to 3C-SiC,6H-SiC,and turbostratic BN(C)phases and Ta_(4)HfC_(5) retained the form of the *** the in situ generations of 2.5 wt% Ta_(4)HfC_(5),Ta_(4)HfC_(5) is preferentially distributed within the turbostratic BN(C);however,as Ta_(4)HfC_(5) content further raised to 10 wt%,it mainly distributed in the grain-boundary of BN(C) and *** introduction of Ta_(4)HfC_(5) nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics,reaching to 344.1 MPa and 4.52 MPa·m^(1/2),*** work has solved the problems of uneven distribution of ultra-high temperature phases in the ceramic matrix,which is beneficial to the real applications of SiBCN ceramics.

关键词： Ta_(4)HfC_(5) SiBCN microstructure evolution mechanical properties

Effects of Fiber Surface Pretreatment and Composite Posttreatment on Mechanical Properties of 2D⁃Cf/Phosphate Geopolymer Matrix Composites

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Journal of Harbin Institute of Technology(New Series) 2020年第3期27卷 233-242页

作者： peigang he Zhanlin Jia Shuai Fu Jiatao Wang Xiaoming Duan Zhihua Yang Dechang Jia Yu Zhou Institute for Advanced Ceramics Department of Materials ScienceHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural⁃Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China

Geopolymers are an important class of materials with potential applications because of their heat resistance,flame resistance,environmental friendliness,and possibilities of being transformed into ceramic matrix composites at low ***,the low mechanical properties as well as the intrinsic brittleness limit their technological implementations,and it is necessary to enhance the mechanical properties of geopolymers by adopting various kinds of *** this work,therefore,two⁃dimensional continuous carbon fiber(Cf)reinforced phosphate⁃based geopolymer composites(Cf/geopolymer)were prepared through ultrasonic⁃assisted impregnation *** of acetone treatment and high⁃temperature treatment on the properties of Cf/geopolymer composites were studied by X⁃ray photoelectron spectroscopy(XPS),X⁃ray diffraction(XRD),and scanning electron microscopy(SEM).Results of the study proved that acetone treatment plays a key role in ameliorating the interfacial interaction between Cf and phosphate matrix,which can thus enhance the mechanical properties of Cf/geopolymer *** Cf/geopolymer composites prepared by acetone⁃treated Cf had a flexural strength of 156.1 MPa and an elastic modulus of 39.7 GPa in Y ***,an additional Sol⁃SiO2 re⁃impregnation treatment could further enhance the mechanical properties of the acetone⁃treated Cf/geopolymer composites by repairing the cracks and filling the *** results in this paper not only provide insights into the surface modification of Cf,but also report a facile and low⁃cost preparation route for Cf/geopolymer composites with potential applications in aerospace and defense technology.

关键词： geopolymer carbon fiber composite surface modification mechanical properties

First-principles study of the anisotropic thermal expansion and thermal transport properties in h-BN

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Science China Materials 2021年第4期64卷 953-963页

作者： Bo Niu Lixiang Zhong Wei Hao Zhihua Yang Xiaoming Duan Delong Cai peigang he Dechang Jia Shuzhou Li Yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore

The thermal expansion coefficient(TEC)and thermal conductivity(k)of thermal fillers are key factors for designing thermal management and thermal protection composite *** to its unique advantages,hexagonal boron nitride(h-BN)is one of the most commonly used thermal ***,its TEC and k values are still unclear due to the inconsistency of characterization techniques and sample *** this work,these disputes were addressed using the quasi-harmonic approximation(QHA)method and phonon Boltzmann transport equation(BTE)theory based on the density functional theory(DFT),*** accuracy of our calculated TEC and k values was confirmed by previously reported experimental results,and the underlying physical principles were analyzed from the phonon *** TEC results show that the h-BN has small in-plane negative value and large cross-plane positive value,which are-2.4×10^(-6) and 36.4×10^(-6) K^(-1) at 300 K,*** the anisotropic TEC is mainly determined by the anisotropic isothermal bulk modulus and the low-frequency out-of-plane longitudinal phonon *** found that the convergence of cutoff radius and q-grid size have significant effect on the accuracy of k of *** results show that the in-plane k is much higher than the cross-plane k,and the values at 300 K are 286.6 and 2.7 W m^(-1) K^(-1),*** anisotropic phonon group velocity arising from the vibration behaviors of acoustic phonon modes should be primarily responsible for the anisotropic *** calculated TEC and k values will provide important references for the design of h-BN composite materials.

关键词： h-BN thermal expansion coefficient thermal conductivity phonon behaviors density functional theory