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Journal of Advanced Ceramics 2012年第1期1卷 38-49页

作者： danyu jiang State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsShanghai 200050China

The indentation hardness of a given material is usually load-dependent and such a phenomenon is generally referred to as the indentation size effect(ISE).The existence of ISE means that,if hardness is used as a material selection criterion,it is clearly insufficient to quote a single hardness *** empirical or semi-empirical equations,including the Meyer’s law,the Hays-Kendall approach,the energy-balance approach,the proportional specimen resistance(PSR)model and the modified PSR model,etc.,have been proposed for the description of the variation of the indentation size with the applied test load and for determining the so-called load-independent *** paper reviews these existing empirical equations,with a special emphasis on the analysis and the application of the modified PSR model.

关键词： indentation hardness size effect residual stress

Determination of the Weibull parameters from the mean value and the coefficient of variation of the measured strength for brittle ceramics

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Journal of Advanced Ceramics 2017年第2期6卷 149-156页

作者： Bin DENG danyu jiang Department of the Prosthodontics Chinese PLA General Hospital Beijing 100853 China Analysis and Testing Center for Inorganic Materials State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Shanghai 200050 China

Accurate estimation of Weibull parameters is an important issue for the characterization of the strength variability of brittle ceramics with Weibull *** this paper,a simple method was established for the determination of the Weibull parameters,Weibull modulus m and scale parameter σ0,based on Monte Carlo *** was shown that an unbiased estimation for Weibull modulus can be yielded directly from the coefficient of variation of the considered strength ***,using the yielded Weibull estimator and the mean value of the strength in the considered sample,the scale parameter σ0 can also be estimated accurately.

关键词： Weibull distribution Weibull parameters strength variability unbiased estimation coefficient of variation

Determination of the load-independent hardness by analyzing the nanoindentation loading curves: A case study on fused silica

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Journal of Advanced Ceramics 2019年第4期8卷 583-586页

作者： Yunbiao DUAN danyu jiang Jin HU Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsShanghai 200050China

The nanoindentation loading curves measured on fused silica were analyzed based on the theoretical relationship derived by Malzbender et al.(J Mater Res 2000, 15: 1209–1212). It was found that the ratio of the applied load to the square of the displacement, P/(h+h_d)~2, does not keep constant during loading segment of the nanoindentation test. Considering the existence of the indentation size effect, an empirical method for the determination of the load-independent hardness by analyzing the nanoindentation loading curves was proposed.

关键词： nanoindentation loading curve indentation size effect(ISE) fused silica

An abnormal displacement change during holding period in nanoindentation tests on zirconia dental ceramic

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Journal of Advanced Ceramics 2016年第2期5卷 153-158页

作者： Lixian ZHANG Longquan SHAO Lei LI danyu jiang Department of Prosthodontics the First Hospital of Yunnan Province Kunming 650000 China Department of Stomatology Nanfang Hospital Southern Medical University Guangzhou 510515 China Analysis and Testing Center for Inorganic Materials the State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Shanghai 200050 China

An abnormal displacement change observed during the holding period in nanoindentation tests on a zirconia dental ceramic was reported in this paper. It was found that, at the initial stage of the holding period, the measured displacement versus time curves were similar in shape with the typical indentation creep curve reported in previous studies. As the holding lasted for long time, however, an evident reduction in displacement was observed for tests with high loading rate, implying that another unknown process, which might result in a decrease in displacement, would co-exist with creep during holding period. Elastic recovery was suggested to be one of the possible sources for such a displacement reduction. An empirical method was also proposed to eliminate the effect of this displacement reduction on the determination of hardness and Young's modulus.

关键词： zirconia nanoindentation displacement elastic recovery

Recent development of A_2B_2O_7 system transparent ceramics

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Journal of Advanced Ceramics 2018年第4期7卷 289-306页

作者： Zhengjuan WANG Guohong ZHOU danyu jiang Shiwei WANG State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Key Laboratory of Transparent Opto-functional Inorganic Materials Shanghai Institute of Ceramics Chinese Academy of Sciences

A_2B_2O_7 system compounds, which usually present three phase structures mainly based on the ionic radius ratios of r_A and r_B(r_A/r_B), have been studied for potential applications in many fields, such as thermal barrier coatings, luminescence powders, fast-ion conductors, photocatalysts, and matrices for immobilization of highly active radionuclides. Since 2005, La_2Hf_2O_7 was fabricated into transparent ceramics and much more attentions were paid on A_2B_2O_7 transparent ceramics for new applications. In this review, the development of A_2B_2O_7 system transparent ceramics was described. The structure characteristics, powder synthesis method, and sintering techniques of the final A_2B_2O_7 transparent ceramics were summarized. After that, the mostly reported A_2Hf_2O_7, A_2Zr_2O_7, and A_2Ti_2O_7 system transparent ceramics were systematically introduced. The potential application fields and future development trends were also discussed, focusing on scintillators, optical elements, and other luminescent materials.

关键词： A2B2O7 system transparent ceramics powder synthesis sintering potential applications

Bi/Bi_2O_3 sensor for quantitation of dissolved oxygen in molten salts

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Journal of Advanced Ceramics 2018年第1期7卷 1-4页

作者： Huiping ZHENG Hongqiang NIAN Jinfeng XIA Guohong ZHOU danyu jiang Qiang LI East China Normal University Shanghai Institute of Ceramics Chinese Academy of Sciences

To quantify the oxygen content in molten salts, we examined the performance of an yttria-stabilized zirconia solid electrolyte oxygen sensor with a Bi/Bi203 reference electrode, focusing on its output accuracy. When the above sensor was tested in a flow of gas with known oxygen partial pressure, P02, a linear relationship between lgp% and the electromotive force （EMF） was observed, and the correlation slope exhibited a positive deviation from Nernstian behavior. EMF measurements performed in molten NaC1-KC1 indicated that the oxygen content of this salt mixture increased with increasing oxygen partial pressure in the covering gas, in agreement with Henry＇s law. Moreover, the EMF exhibited a linear decrease with increasing melt temperature of molten NaC1-KC1, in agreement with the theoretical model. Finally, a relationship between the structure of molten NaC1-KC1 and its oxygen diffusion behavior was established. As a result, the developed sensor was demonstrated to be well suited for determining the oxygen content of molten salts.

关键词： molten salt oxygen sensor Bi/Bi203 oxygen content

Densification and Microstructure of β-sialon/Nano-size SiC Composites

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Journal of Materials Science & Technology 1997年第4期13卷 339-341页

作者： Cheng ZHANG danyu jiang Qiang LI and Weiying SUN (Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China) Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

β-sialon/nano-size SiC composite ceramic with DyAG(Dy3Al5O12) as grain boundary phase was fabricated through hot-pressing. The effect of nano-size SiC on densification, phase composition, microstructure and mechanica... 详细信息

关键词： Nano SiC Densification and Microstructure of sialon/Nano-size SiC Composites

Microstructure and Mechanical Properties of Dy-α-sialon/Nano-size SiC Composites

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Journal of Materials Science & Technology 1997年第4期13卷 336-338页

作者： danyu jiang Chen ZHANG Jianlin SHI Tingrong LAI and Dongsheng YAN(Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China) Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

The composite of Dy-α-sialon/10 wt pct nano-size SiC particles has been prepared from precursor powders of Si3N4, AIN, Al2O3, Dy2O3 and nano-size β-SiC. The hardness, toughness and bending strength of the composite at ambient temperature are a little higher than those of Dy-α-*** the bending strength is maintained up to 1000℃ and about 2 times more than that of Dy-α-sialon at the same temperature. The fracture surfaces show that the grain size of the composite is smaller than that of Dy-α-sialon, and both Of them have predominately transgranular mode of fracture. It is believed that the decrease of the bending strength of Dy-α-sialon at elevated temperature is caused by the viscous flow of the grain boundary phase, while the addition of nanosize SiC particles effectively increases the viscosity of the grain boundary phase and therefore prevents the strength loss of Dy-α-sialon/nano-size SiC composites at elevated temperature

关键词： Microstructure and Mechanical Properties of Dy sialon/Nano-size SiC Composites SiC Nano

Influence of equiatomic Zr/(Ti,Nb)substitution on microstructure and ultra-high strength of(Ti,Zr,Nb)C medium-entropy ceramics at 1900℃

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Journal of Advanced Ceramics 2022年第9期11卷 1457-1465页

作者： Qingqing YANG Xingang WANG Weichao BAO Ping WU Xiaofei WANG Xiaojie GUO Cheng ZHANG Guojun ZHANG danyu jiang State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China School of Materials Science and Engineering Shanghai Institute of TechnologyShanghai 201418China Institute of Functional Materials Donghua UniversityShanghai 201620China

High-temperature mechanical properties of medium-entropy carbide ceramics have attracted significant *** the microstructure is an effective way to improve these high-temperature mechanical properties,which can be affected by the evolution of the enthalpy and entropy,as well as by lattice distortion and sluggish *** this study,the effects of equiatomic Zr/(Ti,Nb)substitution(Zr content of 10-40 at%)on the microstructure and high-temperature strength of(Ti,Zr,Nb)C medium-entropy ceramics were *** grain size of the(Ti,Zr,Nb)C medium-entropy ceramics was refined from 9.4±3.7 to 1.1±0.4μm with an increase in the Zr content from 10.0 to 33.3 at%.A further increase in the Zr content to 40 at%resulted in a slight increase in the grain *** 1900℃,the(Ti,Zr,Nb)C medium-entropy ceramics with the Zr contents of 33.3 and 40 at%exhibited ultra-high flexural strengths of 875±43 and 843±71 MPa,respectively,which were higher than those of the transition metal carbides previously reported under similar ***,relatively smooth grain boundaries,which were detected at a test temperature of 1000℃,transformed into curved and serrated boundaries as the temperature increased to 1900℃,which may be considered the primary reason for the improved high-temperature flexural *** associated mechanism was analyzed and discussed in detail.

关键词： medium entropy mechanical property ultra-high temperature ceramics(UHTCs) nonequimolar compositions curved and serrated grain boundaries

The Research of Connection between Degree of Polymerization and Frequency Domain Dielectric Spectroscopy Characteristics during Oil-Paper Insulation Aging

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Energy and Power Engineering 2017年第4期9卷 667-674页

作者： danyu jiang Guangning Wu Xian Yang Qingkai Hao ASchool of Electrical Engineering College Southwest Jiaotong University Chengdu China Electric Power Research Institute of Guangdong Power Grid Corporation Guangzhou China

In order to study the linkage effects between degree of polymerization and frequency domain dielectric spectroscopy characteristics of oil-paper insulation, the frequency domain dielectric response test platform of oil-paper insulation is set up. Complex permittivity of oil-paper insulation respectively composed by new or aged oil and insulation paper with different DP are tested, and complex permittivity of oil-paper insulation respectively composed by insulation respectively composed by new oil and insulation paper with different DP and low or high moisture content are tested. The test results are analyzed, and the analysis results show that the degree of polymerization of insulation paper has an influence on complex permittivity of oil-paper insulation though influencing the distribution of moisture and acids between oil and paper.

关键词： Degree of Polymerization Oil-Paper Insulation Frequency Domain Dielectric Spectroscopy Moisture