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81.
Hydrothermal Corrosion of Alumina Ceramics 总被引:1,自引:0,他引:1
The corrosion behavior and strength degradation of alumina ceramics with 99%, 99.9%, and 99.99% Al2 O3 were studied in water at 300°C and 8.6 MPa for 1 to 10 d. The weight loss in alumina ceramics was mainly attributed to the dissolution of SiO2 and Na2 O grain-boundary impurities. Intergranular corrosion proceeded in the alumina ceramics by preferential attack at the grain boundaries. The extent of the strength reduction for corroded alumina ceramics was related to the impurity level in the alumina ceramics. 相似文献
82.
83.
Tomoya Nagira Shugo Morita Hiroyoshi Yokota Hideyuki Yasuda Christopher M. Gourlay Masato Yoshiya Akira Sugiyama Kentaro Uesugi Akihisa Takeuchi Yoshio Suzuki 《Metallurgical and Materials Transactions A》2014,45(12):5613-5623
Synchrotron X-ray radiography at 125 frames per second was used to study deformation mechanisms in semi-solid Fe-C alloys at high solid fraction and shear strain rates of 10?1/s. An image correlation approach was also used to quantify the shear strain fields and study shear-induced dilation and the origin of shear cracking. It was shown that, at high solid fraction (90 to 93 pct solid), rearrangement including rotation and translation of solid particles became restricted and shear strain localized into narrow liquid-filled channels/fissures. Shear cracking was shown to originate from inadequate liquid flow into the expanding spaces between solid particles caused by shear-induced dilation. At lower solid fraction (~85 pct solid), solid particles rearranged with a significantly higher component of rotation leading to more shear-induced dilation and a wider shear band. 相似文献
84.
Hasegawa Tatsuro Yamauchi Hisashi Sashida Yoshio Matsumoto Mitsuo 《Industrial Electronics, IEEE Transactions on》1985,(3):253-260
Recent application of distributed control systems to large-and medium-scale industrial plants requires effective and high-speed communication among the control devices each other to ensure high-performance operation. 相似文献
85.
In this paper, the numerical analysis is given which is applicable for a TEA-CO2 laser pumping in search of effective pumping method. The analysis also can estimate the optimum pressure for a given molecule and a given pulse laser. Also we report in this work many FIR laser emissions from population inversion transition which have never observed before using a TEA-CO2 laser. 相似文献
86.
Oleg Vasylkiv Yoshio Sakka Yasuaki Maeda Valeriy V. Skorokhod 《Journal of the American Ceramic Society》2005,88(3):639-644
A uniformly aggregated 3 mol% yttria-stabilized tetragonal zirconia nano-powder (3Y-TZP) was prepared using thermal hydrolysis and the ultrasonic deagglomeration technique. The possibility of nano-engineering of Pt–3Y-TZP composite aggregates was studied. The as-synthesized Pt nano-particles (∼2 nm) were impregnated into zirconia nano-aggregates (20–45 nm). The morphology manipulation technique allowed production of the composite zirconia-based aggregates in which a significant fraction of the Pt particles was embedded into the densified zirconia aggregates. Using the colloidal technique and low-temperature (1150°C) sintering, we prepared the Pt-zirconia (0.5–1.5 wt% of platinum) nano-composites with average 3Y-TZP grain sizes of 120 nm, and with the platinum grains size in the range of 20–60 nm. The catalytic properties of composite Pt–3Y-TZP nano-composites were studied and described. 相似文献
87.
A relationship between emission characteristics of Ba atom as an emitter material and temperature distributions of an electrode in a fluorescent lamp is described, which is measured by using laser-induced fluorescence and black-body radiation method, respectively. In a virgin lamp, a hot spot observed at the electrode edge connected to the power supply is the main source of Ba atom emission. In a long-term-used lamp, it is shown that Ba atom emission, thermionic electron emission in cathode half-cycle and electron collection in anode half-cycle are most active on the hot spot appearing on the center of the electrode. 相似文献
88.
Shinichi Yamamoto Yoshio Ohashi Yuji Masubuchi Takashi Takeda Teruki Motohashi Shinichi Kikkawa 《Journal of Alloys and Compounds》2009,482(1-2):160-163
Oxynitrides in the (Nb1−xAlx)(O,N) quaternary system were prepared by ammonolysis of oxide precursor obtained through the citrate route. The products at 1000 °C were a mixture of Nb(N,O) and NbN0.95 at the niobium end (x = 0) and amorphous Al(O,N) at the aluminum end (x = 1). A new cubic compound (A) appeared mixed with Nb(N,O) in the compositional range 0.1 ≤ x ≤ 0.4. Its almost pure product was obtained at x = 0.5. The X-ray diffraction pattern was rock salt type (Nb0.56Al0.44)(O0.38N0.37□025) in Fm−3m with a = 0.43481(1) nm. The product showed superconductivity with Tc = 15 K. Its crystallinity was much improved and its superconducting volume fraction increased to 32% after its thermal annealing at 1100 °C in evacuated sealed tube. A second cubic compound (B), rock salt type Nb[(O,N)0.85□0.15] with a = 0.434 nm, was observed mixed with amorphous Al(O,N) in the as-prepared products of the range 0.6 ≤ x ≤ 0.9. 相似文献
89.
Yoshio Akimune 《Journal of Materials Science》1990,25(8):3439-3448
Four types of SiC-whisker/silicon nitride and SiC-particle/silicon nitride composites were produced, and their mechanical properties and impact damage behaviour examined. All of the composites exhibited elastic response behaviour at spherical impact with Hertz cone crack initiation. Impact resistance behaviour, however, was different for each composite. This was due to the different mechanical properties produced by their microstructures. A SiC-platelet/silicon nitride composite displayed the highest resistance to crack initiation and propagation, which resulted in high impact resistance to strength degradation. On the other hand, SiC-particle/silicon nitride, SiC-whisker/silicon nitride, and large SiC-whisker/silicon nitride composites showed less impact resistance, even though they have higher mechanical properties such as bending strength and fracture toughness. 相似文献
90.
Biodegradable polymeric composites were fabricated from poly(butylene succinate) (PBS) and kenaf fiber (KF) by melt mixing technique. The mechanical and dynamic mechanical properties, morphology and crystallization behavior were investigated for PBS/KF composites with different KF contents (0, 10, 20, and 30 wt %). The tensile modulus, storage modulus and the crystallization rate of PBS in the composites were all efficiently enhanced. With the incorporation of 30% KF, the tensile modulus and storage modulus (at 40°C) of the PBS/KF composite were increased by 53 and 154%, respectively, the crystallization temperature in cooling process at 10°C/min from the melt was increased from 76.3 to 87.7°C, and the half‐time of PBS/KF composite in isothermal crystallization at 96 and 100°C were reduced to 10.8% and 14.3% of that of the neat PBS, respectively. SEM analysis indicates that the adhesion between PBS and KF needs further improvement. These results signify that KF is efficient in improving the tensile modulus, storage modulus and the crystallization rate of PBS. Hence, this study provides a good option for preparing economical biodegradable composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献