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51.
Farzad Shayesteh Seyed Ali Delbari Zohre Ahmadi Mohammadreza Shokouhimehr Mehdi Shahedi Asl 《Ceramics International》2019,45(5):5306-5311
In this study, the impact of TiN as a sintering aid on the relative density and microstructure of TiB2 ceramic was investigated. Monolithic TiB2 and TiB2 doped with 5?wt% TiN were sintered at 1900?°C for 7?min dwell time under the pressure of 40?MPa by spark plasma. The addition of TiN affected the microstructure of TiB2-based sample considerably depicting the finer grains in the as-sintered ceramic. X-ray diffraction evaluation indicated that no interaction occurred between the initial materials. However, detail investigation by the map analysis and energy dispersive spectroscopy results revealed the formation of in-situ nano-sized hBN secondary phase in the TiN-doped TiB2. In addition, TiN played a remarkable role on increasing the relative density of TiN-doped TiB2 ceramic producing a nearly fully dense ceramic with relative density of 99.9% in comparison with the monolithic ceramic having 96.7% relative density. 相似文献
52.
Legan Hou Tianzi Wang Ruizhi Wu Jinghuai Zhang Milin Zhang Anping Dong Baode Sun Sergey Betsofen Boris Krit 《材料科学技术学报》2018,34(2):317-323
Ultrafine-grain and high-strength Mg-5Li-1Al sheets were prepared by accumulative roll bonding (ARB) process. Evolution of microstructure and mechanical properties of ARB-processed Mg-5Li-1Al sheets was investigated.Results show that, during ARB process, the evolution of deformation mechanism of t Mg-5Li-1Al alloy is as follows: twinning deformation, shear deformation, forming macro shear zone, and finally dynamic recrystallization (DRX). The grain refining mechanism changes from twin DRX to rotation DRX. With the increase in ARB cycles, strength of the Mg-5Li-1Al sheets is enhanced, whilst elongation varies slightly. With the increase in rolling cycles, anisotropy of mechanical properties decreases. It is conclusive that strain hardening and grain refinement dominate the strengthening mechanism of Mg-5Li-1Al alloy. 相似文献
53.
Chicken breast quality – normal,pale, soft and exudative (PSE) and woody – influences the functional properties of meat batters 下载免费PDF全文
Hongqiang Chen HuHu Wang Jun Qi Mengyao Wang Xinglian Xu Guanghong Zhou 《International Journal of Food Science & Technology》2018,53(3):654-664
Three classes (normal, PSE‐like and woody, thirty for per class) of fresh chicken breast meats were selected from a Chinese processing plant. Then, three classes of chicken breast meats were used to prepare meat batters and meatballs. This study investigated the effects of three classes of chicken breast meat on the physicochemical properties, water distribution, protein secondary structures and microstructures of meatballs. PSE‐like and woody meatballs both had lower water holding capacity and textural properties than normal meatballs. Furthermore, the free water mobility and proportion in PSE‐like and woody meatballs were increased (P < 0.05). According to near‐infrared spectroscopy results, the intensity of the 1940‐nm bands of PSE‐like and woody classes both increased. Both PSE‐like and woody meatballs formed more aggregated gel matrices than normal class. PSE‐like and woody classes had higher α‐helix and lower β‐structure contents (P < 0.05). Overall, compared with normal meatballs, PSE‐like and woody meatballs showed inferior functional properties. 相似文献
54.
Hainan Bai Jiulin Hu Xiaoguang Li Yusen Duan Feng Shao Takahiro Kozawa Makio Naito Jingxian Zhang 《Ceramics International》2018,44(6):6558-6563
Concerning the safety problems of conventional Li-ion batteries with liquid electrolytes, it is crucial to develop reliable solid-state electrolytes with high ionic conductivity. Li1+xAlxTi2?x(PO4)3 (LATP, x = 0.3) is regarded as one of the most promising solid electrolytes due to its high ionic conductivity and excellent chemical stability to humidity.Herein, a new strategy is proposed for improving the sintering behavior and enhancing the ionic conductivity of LATP by using LiBO2 as the sintering aid via liquid phase sintering. The as-prepared sample LATP with homogeneous microstructure and high relative density of 97.1% was successfully synthesized, yielding high total ionic conductivity of 3.5 × 10?4 S cm?1 and low activation energy of 0.39 eV at room temperature. It was found that the addition of LiBO2 could effectively enhance the densification and increase the ionic conductivity of LATP electrolyte, proving an effective way to synthesis LATP ceramics by a simple and reliable route. 相似文献
55.
Feiyue Yang Yiwen Yao Zichun Yang Shuang Zhao Guobing Chen Kunfeng Li 《Ceramics International》2021,47(13):18351-18357
To meet demand for lightweight and high-strength ceramic foams, in-situ self-reinforced Si3N4 ceramic foams, with compressive strength of 13.2–45.9 MPa, were fabricated by protein foaming method combined with sintered reaction-bonded method. For comparison, ordinary protein foamed ceramics with irregular block microstructure were fabricated via reaction-bonded method, which had compressive strength of 3.6–20.5 MPa. Physical properties of these two types of samples were systematically compared. When open porosity was about 80%, both types of Si3N4 ceramic foams had excellent thermal insulation properties (<0.15 W m?1 K?1), while compressive strength of in-situ self-reinforced samples increased by more than 158% compared with ordinary samples. Under high-temperature oxidation conditions, microstructures of both types of samples were deformed with increase in oxidation temperature. Moreover, after oxidation temperature was increased to 1400 °C, oxidation weight gain decreased from 18.07% for ordinary samples to only 2.18% for self-reinforced samples. Thus, high-temperature oxidation resistance of Si3N4 ceramic foams was greatly improved. 相似文献
56.
N.A. Zhuk M.G. Krzhizhanovskaya N.A. Sekushin V.V. Kharton B.A. Makeev V.A. Belyy R.I. Korolev 《Ceramics International》2021,47(14):19424-19433
The solid solutions based on the pyrochlore-type system Bi2MgNb2-xTaxO9 were formed in the compositional range х = 0–2.0 (Bi1·6Mg0·8Nb1.6-tTatO7.2, t = 0–1.6). The Rietveld method was used to refine the structure for Bi2MgNb2-xTaxO9 (x = 0, 1.0, 2.0). The increasing tantalum content led to the slight decrease in the cubic unit cell parameters from 10.56934 (4) Å for x = 0 and 10.54607 (3) Å for x = 2 (sp.gr. Fd-3m:2). At the same time, tantalum additions suppressed grain growth in the pyrochlore ceramics during sintering and made it possible to obtain materials with an average grain size of 1–2 μm (Bi1·6Mg0·8Ta1·6O7.2). The increase in the Ta5+ concentration led to the decrease in the dielectric permeability from 104 (Bi1·6Mg0·8Nb1·6O7.2) to 20 (Bi1·6Mg0·8Ta1·6O7.2) at room temperature, while the dielectric loss tangent remained lower than 0.002, which is due to the small grain size and the high porosity of the samples. An increase in temperature has practically no effect on the values of the dielectric permittivity in the entire frequency range. The samples have weak through conductivity. The activation energies of electrical conductivity varied in the range of 0.84–1.00 eV, and the less tantalum, the lower the activation energy. The electrical properties of the samples at 200 Hz to 1 MHz are described by the simplest parallel scheme. 相似文献
57.
Shiva Bejugama Shibu Chameettachal Falguni Pati Ajoy Kumar Pandey 《Ceramics International》2021,47(2):1594-1601
Niobia (1 mol. %) doped Ceria Stabilized Zirconia (NbCSZ) powders were synthesized using a co-precipitation method. The synthesized powders were uniaxially compacted and sintered in air. The two-step sintering method was adopted to sinter the samples, and the sintering schedule was optimized based on density, grain size, the phase present, and the hardness of the sintered sample. It was observed that the two-step sintering method effectively suppressed the grain growth of NbCSZ samples and helped in achieving a finer grain size of 1.57 μm along with the hardness of 1195 HV10 and optimum fracture toughness value 6.20 MPa m1/2. The Low-Temperature Degradation (LTD) behavior of the sintered samples was estimated through an accelerated hydrothermal aging test, which revealed that the samples are highly resistant to LTD and shown no phase change even after 150 h of study. Moreover, the cytocompatibility of the NbCSZ was tested by culturing MG63 cells on the samples for 7 days. The NbCSZ was found to be highly biocompatible as evident from cell viability and metabolic activity assay. 相似文献
58.
Camila Konno Clarissa Cruz Thiago Costa André Barros Pedro Goulart Amauri Garcia Noé Cheung 《International Journal of Hydrogen Energy》2021,46(24):12654-12671
This work deals with the development of quantitative correlations of hydrogen evolution performance with solidification microstructural and thermal parameters in Al–1Sn, Al–2Sn, Al–1Fe, and Al-1.5Fe [wt.%] alloys. The cellular growth as a function of growth and cooling rates is evaluated using power type experimental laws, which allow determining representative intervals of microstructure length scale for comparison purposes with the results of immersion tests in 5 wt%NaOH solution. For both Al alloys systems, hydrogen evolution becomes slower as the alloy solute content increased. However, for a given alloy composition, whereas a more homogeneous distribution of Sn-rich particles promotes faster hydrogen generation using Al–Sn alloys, coarsening of Al6Fe IMCs (intermetallic compounds) fibers favors hydrogen production using Al–Fe alloys. When solidification conditions that result in a range of cellular spacings within 16 and 19 μm are considered, the specific hydrogen production of the Al-1wt.%Fe alloy is higher than that of the other studied alloys. 相似文献
59.
J. Engels A. Houben P. Hansen M. Rasinski Ch. Linsmeier 《International Journal of Hydrogen Energy》2018,43(51):22976-22985
Steel components are required in the infrastructure and the facilities of the hydrogen economy. The high hydrogen pressures in the hydrogen economy lead to embrittlement and surface corrosion of the steels. For the functionality of the facilities it is necessary to suppress the embrittlement and the surface corrosion of the steels by protective layers, e.g. ceramic thin films. With regard to fusion power plants ceramic thin films on the structural steel materials are also required. These thin films work as a tritium permeation barrier that is necessary to prevent the loss of the radioactive fuel inventory. Oxide thin films, e.g. Al2O3, Er2O3, and Y2O3, are promising candidates as tritium permeation barrier layers. In terms of the application in the first wall, this is especially true for yttrium due to its favorably short decay time after neutron activation compared to the other candidates. The Y2O3 layers with thicknesses of 0.5 μm–1 μm are deposited on both substrate sides by RF magnetron sputter deposition. Since the microstructure of the barrier layer plays an important role for the permeation reduction, layers with three different magnetron process modes and thus three different microstructures are prepared. After annealing the cubic crystal structure of all thin films is verified by X-ray diffraction and the different microstructures are investigated by scanning electron microscopy and transmission electron microscopy. The Y2O3 stoichiometry of all thin films and a chromium oxide material segregation at the interface are verified by analysis methods such as X-ray photoelectron spectroscopy. The permeation reduction factors of all thin films are determined in gas-driven deuterium permeation experiments. Corresponding to the three different microstructures, reduction factors of 25, 45, and 1100 are identified. Thus, the permeation reduction is strongly dependent on the Y2O3 microstructure. The measurement results suggest that a high density of grain boundaries leads to a high hydrogen permeation. 相似文献
60.
《Calphad》2020
Phase equilibria in the ternary Cu–Zr–Si system at 750 and 900 °C have been experimentally investigated via electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD) analysis on the equilibrated alloys. The results show the presence of eight three-phase regions at 750 °C and seven three-phase regions at 900 °C. Four ternary phase: τ1 (Zr3Cu4Si6, tI26-Zr3Cu4Si6), τ4 (Zr3Cu4Si4, oI22-Gd3Cu4Ge4), τ5 (ZrCuSi, oP12-Co2Si), and τ6 (Zr3Cu4Si2, 2hP9-Fe2P) were confirmed to exist in the Cu–Zr–Si ternary system at 750 and 900 °C. At 900 °C, the dark gray phase, the chemical composition of which is close to η-Cu3Si, is confirmed to be the liquid phase. Moreover, the solubilities of Cu in ZrSi2, SiZr and Zr3Si2 are considerably small. The solubility of Zr in η-Cu3Si is determined to be negligible. The newly determined phase equilibria of the Cu–Zr–Si system in this work can provide important experimental data for the thermodynamic assessment of the Cu–Zr–Si system and to develop the Cu–Zr–Si alloys and related transition metal silicides. 相似文献