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Synthesis and property characterization of ternary laminar Zr_(2)SB ceramic

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Journal of Advanced Ceramics 2022年第5期11卷 825-833页

作者： Qiqiang ZHANG Shuai FU detian wan Yiwang BAO Qingguo FENG Salvatore GRASSO Chunfeng HU Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Green Building Materials China Building Materials AcademyBeijing 10000China

In this paper,Zr_(2)SB ceramic with purity of 82.95 wt%(containing 8.96 wt%ZrB_(2)and 8.09 wt%zirconium)and high relative density(99.03%)was successfully synthesized from ZrH_(2),sublimated sulfur,and boron powders by spark plasma sintering(SPS)at 1300℃.The reaction process,microstructure,and physical and mechanical properties of Zr_(2)SB ceramic were systematically studied.The results show that the optimum molar ratio to synthesize Zr_(2)SB is n(ZrH_(2)):n(S):n(B)=1.4:1.6:0.7.The average grain size of Zr_(2)SB is 12.46μm in length and 5.12μm in width,and the mean grain sizes of ZrB2 and zirconium impurities are about 300 nm.In terms of physical properties,the measured thermal expansion coefficient(TEC)is 7.64×10^(-6) K^(-1) from room temperature to 1200℃,and the thermal capacity and thermal conductivity at room temperature are 0.39 J·g^(-1)·K^(-1)and 12.01 W·m^(-1)·K^(-1),respectively.The room temperature electrical conductivity of Zr_(2)SB ceramic is measured to be 1.74×10^(6)Ω^(-1)·m^(-1).In terms of mechanical properties,Vickers hardness is 9.86±0.63 GPa under 200 N load,and the measured flexural strength,fracture toughness,and compressive strength are 269±12.7 MPa,3.94±0.63 MPa·m1/2,and 2166.74±291.34 MPa,respectively.

关键词： Zr_(2)SB spark plasma sintering(SPS) reaction path microstructure properties

Hot forging Nb_(4)AlC_(3)ceramics with enhanced properties

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Journal of Advanced Ceramics 2023年第11期12卷 2032-2040页

作者： Ye Yu Shuai Fu detian wan Yiwang Bao Longsheng Chu Qingguo Feng Chunfeng Hu Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Green Building Materials China Building Materials AcademyBeijing 100024China

Textured Nb_(4)AlC_(3)ceramics were rapidly and efficiently prepared by hot forging through spark plasma sintering(SPS).The longitudinal compression ratio of textured Nb_(4)AlC_(3)ceramics was−78.3%,and the lateral expansion ratio was 32.1%.The grains grew preferentially along the direction perpendicular to the c-axis,forming the texture microstructure.The Lotgering orientation factor f(00l)was calculated to be 0.63.The thermal conductivity of textured Nb_(4)AlC_(3)ceramics along the c-axis direction(11.23 W·m^(−1)·K^(−1))(25℃)was lower than that of untextured ceramics(13.75 W·m^(−1)·K^(−1))(25℃).The electrical conductivity perpendicular to the c-axis direction reached 4.37×10^(6) S·m^(−1)at room temperature.The ordered layered grains increased the resistance of crack propagation,resulting in a higher fracture toughness parallel to the c-axis direction(9.41 MPa·m^(1/2)),which was higher than that of untextured ceramics(6.88 MPa·m1/2).The Vickers hardness tested at 10 N on the texture top surface(7.18 GPa)was higher than that on the texture side surface(6.45 GPa).

关键词： Nb_(4)AlC_(3) texture anisotropy microstructure properties

Evaluating high temperature elastic modulus of ceramic coatings by relative method

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Journal of Advanced Ceramics 2017年第4期6卷 288-303页

作者： Guanglin NIE Yiwang BAO detian wan Yuan TIAN State Key Laboratory of Green Building Materials China Building Materials AcademyBeijing 100024China

The accurate evaluation of the elastic modulus of ceramic coatings at high temperature(HT)is of high significance for industrial application,yet it is not easy to get the practical modulus at HT due to the difficulty of the deformation measurement and coating separation from the composite samples.This work presented a simple approach in which relative method was used twice to solve this problem indirectly.Given a single-face or double-face coated beam sample,the relative method was firstly used to determine the real mid-span deflection of the three-point bending piece at HT,and secondly to derive the analytical relation among the HT moduli of the coating,the coated and uncoated samples.Thus the HT modulus of the coatings on beam samples is determined uniquely via the measured HT moduli of the samples with and without coatings.For a ring sample(from tube with outer-side,inner-side,and double-side coating),the relative method was used firstly to determine the real compression deformation of a split ring sample at HT,secondly to derive the relationship among the slope of load-deformation curve of the coated ring,the HT modulus of the coating and substrate.Thus,the HT modulus of ceramic coatings can be evaluated by the substrate modulus and the load-deformation data of coated rings.Mathematic expressions of those calculations were derived for the beam and ring samples.CVD-SiC coatings on graphite substrate were selected as the testing samples,of which the measured modulus ranging from room temperature to 2100℃demonstrated the validity and convenience of the relative method.

关键词： elastic modulus ceramic coatings high temperature(HT) relative method SiC

Study on dynamic response of high speed train window glass under tunnel aerodynamic effects

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Railway Sciences 2023年第2期2卷 211-224页

作者： Xiaogen Liu Shuang Qi detian wan Dezhi Zheng The State Key Laboratory of Green Building Materials China Building Materials AcademyBeijingChina China Testing&Certification International Group Co. LtdChina Building Materials AcademyBeijingChina

Purpose-This paper aims to analyze the bearing characteristics of the high speed train window glass under aerodynamic load effects.Design/methodology/approach-In order to obtain the dynamic strain response of passenger compartment window glass during high-speed train crossing the tunnel,taking the passenger compartment window glass of the CRH3 high speed train onWuhan-Guangzhou High Speed Railway as the research object,this study tests the strain dynamic response and maximum principal stress of the high speed train passing through the tunnel entrance and exit,the tunnel and tunnel groups as well as trains meeting in the tunnel at an average speed of 300 km$h-1.Findings-The results show that while crossing the tunnel,the passenger compartment window glass of high speed train is subjected to the alternating action of positive and negative air pressures,which shows the typical mechanic characteristics of the alternating fatigue stress of positive-negative transient strain.The maximum principal stress of passenger compartment window glass for high speed train caused by tunnel aerodynamic effects does not exceed 5 MPa,and the maximum value occurs at the corresponding time of crossing the tunnel groups.The high speed train window glass bears medium and low strain rates under the action of tunnel aerodynamic effects,while the maximum strain rate occurs at the meeting moment when the window glass meets the train head approaching from the opposite side in the tunnel.The shear modulus of laminated glass PVB film that makes up high speed train window glass is sensitive to the temperature and action time.The dynamically equivalent thickness and stiffness of the laminated glass and the dynamic bearing capacity of the window glass decrease with the increase of the action time under tunnel aerodynamic pressure.Thus,the influence of the loading action time and fatigue under tunnel aerodynamic effects on the glass strength should be considered in the design for the bearing performance of high speed train window glass.Originality/

关键词： High speed train window glass Tunnel aerodynamic effect Strain dynamic response Maximum principal stress Strain rate Bearing characteristics

粉煤灰掺量对轻烧氧化镁基制备3d打印用磷酸镁水泥性能的影响

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功能材料 2024年第3期55卷 3170-3177页

作者：李楠梁云钟建军李维红万德田大连大学建筑工程学院大连116622 中国建筑材料科学研究总院北京100000

以实现轻烧氧化镁为原料制备低碳磷酸镁水泥材料的3d打印为目标,采用自主研发的混搅挤功能一化建筑3d打印设备,探究了不同粉煤灰掺量对以轻烧氧化镁为基制备磷酸镁水泥材料性能与打印性能的影响规律,并结合XRD与SEM微观试验进一步分析... 详细信息

以实现轻烧氧化镁为原料制备低碳磷酸镁水泥材料的3d打印为目标,采用自主研发的混搅挤功能一化建筑3d打印设备,探究了不同粉煤灰掺量对以轻烧氧化镁为基制备磷酸镁水泥材料性能与打印性能的影响规律,并结合XRD与SEM微观试验进一步分析粉煤灰对其水化产物及晶体样貌的影响。结果表明:与重烧氧化镁相比,由轻烧氧化镁制备磷酸镁水泥的凝结时间大幅缩短;粉煤灰的加入对材料凝结时间影响较小,均在2~3 min左右,但对抗压强度与界面粘结强度有负面影响,当粉煤灰掺量为磷酸镁水泥质量的30%时,抗压强度及界面粘结强度分别下降约34.24%、48.94%;粉煤灰掺量在20%以内时,可有效改善轻烧氧化镁基磷酸镁水泥材料的干缩率,提高体积稳定性;粉煤灰中的活性物质参与水化反应,生成的水化产物与磷酸镁水泥展现出良好的化学相容性,使结构内部更为密实;当粉煤灰掺量为20%~25%时,制备的3d打印用轻烧氧化镁基磷酸镁水泥具有良好的工作性能、体积稳定性能、挤出性能以及建造性能,且满足3d打印对水泥基材料的力学要求。

关键词：轻烧氧化镁粉煤灰掺量磷酸镁水泥 3d打印打印性能

A simple way to make pre-stressed ceramics with high strength

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Journal of Materiomics 2019年第4期5卷 657-662页

作者： Yiwang Bao Fenghua Kuang Yi Sun Yueming Li detian wan Zongyang Shen Delong Ma Lingfeng He State Key Laboratory of Green Building Materials China Building Materials AcademyBeijing100000China School of Materials Science and Engineering Jingdezhen Ceramic InstituteJingdezhen333403China Advanced Characterization Department Idaho National LaboratoryIdaho Falls83415IDUSA

A pre-stressing design and a simple fabrication technology to substantially improve the strength of ceramic components are presented.Residual surface compressive stress is generated in ceramic components by pressureless sintering of a green bulk coated with a thin layer of low coefficient of thermal expansion(CTE).The stress level can be controlled by changing the cross-section area ratio,Young's modulus ratio and CTE ratio of the coating.Pre-stressed ZrO_(2) ceramics coated with Al_(2)O_(3) can achieve a flexural strength of 1330±52MPa,45% higher than their uncoated counterpart.Similarly,the flexural strength of building porcelain tiles is increased by 70%,from 67±3 MPa to 114±5MPa.The damage tolerance of pre-stressed ZrO_(2) ceramics is excellent with a high residual strength of ~1200 MPa in a thermal shock test at 325℃.This simple technique can improve the mechanical performance of ceramic components with no limitation of size and shape.

关键词： Pre-stressed ceramics Coating Strength Thermal shock resistance

偏高岭土改性轻烧氧化镁基磷酸镁水泥的3D打印性能

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硅酸盐通报 2024年第5期43卷 1663-1672页

作者：李楠钟建军邓永杰梁云万德田李维红李栋伟大连大学复杂结构系统灾害预测与防治辽宁省重点实验室大连116622 大连大学建筑工程学院大连116622 中国建筑材料科学研究总院有限公司北京100024 大连学庆铭锋数控技术有限公司大连116622

本文采用自主研发的混搅挤功能一体化建筑3D打印设备,实现了轻烧氧化镁基磷酸镁水泥材料的3D打印,探究了不同掺量偏高岭土(MK)对3D打印轻烧氧化镁基磷酸镁水泥性能的影响规律,并结合XRD与SEM试验进一步分析MK掺量对3D打印轻烧氧化镁基... 详细信息

本文采用自主研发的混搅挤功能一体化建筑3D打印设备,实现了轻烧氧化镁基磷酸镁水泥材料的3D打印,探究了不同掺量偏高岭土(MK)对3D打印轻烧氧化镁基磷酸镁水泥性能的影响规律,并结合XRD与SEM试验进一步分析MK掺量对3D打印轻烧氧化镁基磷酸镁水泥水化产物及晶体形貌的影响。结果表明:3D打印轻烧氧化镁基磷酸镁水泥的凝结时间与力学性能均随着MK掺量的增加呈先上升后下降的趋势;当MK掺量为胶凝材料质量的4%~6%时,MK的加入有效改善了轻烧氧化镁基磷酸镁水泥浆体的打印性能,此时的轻烧氧化镁基磷酸镁水泥具有良好的挤出性能、建造性能与力学性能,能够满足3D打印应用要求;MK的加入不会改变轻烧氧化镁基磷酸镁水泥水化产物晶体的组成,但会产生大量无定形的非晶体水化产物,进一步填充水化产物与颗粒间的空隙,改善结构密实程度。

关键词：轻烧氧化镁偏高岭土磷酸镁水泥 3D打印打印性能力学性能

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残余拉应力的温度依赖性及其对裂纹扩展行为的影响

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无机材料学报 2023年第11期38卷 1265-1270页

作者：李海燕旷峰华吴昊龙刘小根包亦望万德田中国国检测试控股集团股份有限公司北京100024 绿色建材国家重点实验室中国建筑材料科学研究总院北京100024

为研究以高膨胀系数的陶瓷为涂层,低膨胀系数的陶瓷为基体的预应力陶瓷的高温力学性能,本工作以氧化锆为涂层,氧化铝为基体,制得表层为拉应力的“三明治”结构ZrO_(2)-Al_(2)O_(3)(简称ZcAs)预应力陶瓷。同时选用基体与涂层截面比值相近... 详细信息

为研究以高膨胀系数的陶瓷为涂层,低膨胀系数的陶瓷为基体的预应力陶瓷的高温力学性能,本工作以氧化锆为涂层,氧化铝为基体,制得表层为拉应力的“三明治”结构ZrO_(2)-Al_(2)O_(3)(简称ZcAs)预应力陶瓷。同时选用基体与涂层截面比值相近的Al_(2)O_(3)-ZrO_(2)(简称AcZs)预应力陶瓷、纯ZrO_(2)和纯Al_(2)O_(3)陶瓷为参照样。结合不同温度下的弯曲强度测试结果及维氏压痕结果,阐明预应力的存在形式及其对裂纹扩展行为的影响,并研究预应力的温度依赖性。结果表明:ZcAs预应力陶瓷的表层受拉应力,基体受压应力;而AcZs预应力陶瓷的表层受压应力,基体受拉应力。由于拉应力能够促进裂纹扩展,而压应力能够抑制裂纹扩展,因此室温下,ZcAs的强度比纯Al_(2)O_(3)陶瓷降低13.2%,而AcZs的强度比纯ZrO_(2)陶瓷提高25.0%。此外,无论表层是拉应力还是压应力,都随着温度升高而降低,这主要归因于高温导致的预应力松弛。

关键词： ZrO_(2)-Al_(2)O_(3)预应力陶瓷拉应力弯曲强度温度依赖性

莫来石/氧化铝预应力涂层增强氧化铝的弯曲强度和抗热震性能

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无机材料学报 2022年第12期37卷 1295-1301页

作者：郝鸿渐李海燕万德田包亦望李月明中国建筑材料科学研究总院有限公司绿色建筑材料国家重点实验室北京100024 中国国检测试控股集团股份有限公司北京100024 景德镇陶瓷大学材料科学与工程学院景德镇333403

在陶瓷表面引入含压应力的涂层是一种有效的增强技术。本研究将氧化铝和石英粉混合浆料涂覆在预烧后的氧化铝坯体上,无压共烧原位合成了热膨胀系数较低的莫来石-氧化铝涂层。利用降温过程中涂层内形成的残余压应力实现了氧化铝陶瓷的预... 详细信息

在陶瓷表面引入含压应力的涂层是一种有效的增强技术。本研究将氧化铝和石英粉混合浆料涂覆在预烧后的氧化铝坯体上,无压共烧原位合成了热膨胀系数较低的莫来石-氧化铝涂层。利用降温过程中涂层内形成的残余压应力实现了氧化铝陶瓷的预应力强化。结果表明:随着涂层中石英掺量增加,预应力氧化铝的强度出现先增大后减小的趋势;当涂层中掺入石英的质量分数为15%时,预应力增强效果最好,涂层与基体界面结合紧密,预应力氧化铝陶瓷的弯曲强度达到(549.44±27.2)MPa,比普通氧化铝的强度提高了37.19%;当涂层中掺入石英的质量分数增大到15%以上,由于烧结收缩不匹配反而引起强度下降;这种预应力增强效果会随着温度升高逐渐减弱,当测试温度达到并超过1000℃时,预应力氧化铝和普通氧化铝会具有大致相等的抗弯强度。由于表层压应力的存在,预应力氧化铝还展现出更好的抗热震性能和损伤耐受性。

关键词：预应力强化氧化铝陶瓷低膨胀系数弯曲强度抗热震性能