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81.
《Ceramics International》2017,43(6):5102-5107
This work aimed to improve the acid resistance of an alumina ceramic. Acid corrosion of alumina ceramic composed of Al2O3-CaCO3-SiO2-MgO-Y2O3 (ACSMY) was investigated in a hydrochloric-hydrofluoric acid solution at 65 °C for 30 min. The effect of Y2O3 content on sintering temperature, density, and acid solubility were discussed. The composition and microstructure of this material were analyzed. The acid solubilities of minor crystal phases (Y3Al5O12, CaAl12O19, Ca2Al2SiO7, and CaAl2Si2O8) and the effect of them on acid resistance of this alumina ceramic were studied. The results showed that Y2O3 additive can enhance density and change the type of phases. Phases with good acid resistance and dense structure lead to a crust formed on the surface of ceramic during acid corrosion. The crust can effectively protect the interior structure of the sample from acid solution, and then improve the acid resistance of the material. 相似文献
82.
G. Taillades J. Dailly M. Taillades‐Jacquin F. Mauvy A. Essouhmi M. Marrony C. Lalanne S. Fourcade D. J. Jones J.‐C. Grenier J. Rozire 《Fuel Cells》2010,10(1):166-173
A proton conducting ceramic fuel cell (PCFC) operating at intermediate temperature has been developed that incorporates electrolyte and electrode materials prepared by flash combustion (yttrium‐doped barium cerate) and auto‐ignition (praseodymium nickelate) methods. The fuel cell components were assembled using an anode‐support approach, with the anode and proton ceramic layers prepared by co‐pressing and co‐firing, and subsequent deposition of the cathode by screen‐printing onto the proton ceramic surface. When the fuel cell was fed with moist hydrogen and air, a high Open Circuit Voltage (OCV > 1.1 V) was observed at T > 550 °C, which was stable for 300 h (end of test), indicating excellent gas‐tightness of the proton ceramic layer. The power density of the fuel cell increased with temperature of operation, providing more than 130 mW cm–2 at 650 °C. Symmetric cells incorporating Ni‐BCY10 cermet and BCY10 electrolyte on the one hand, and Pr2NiO4 + δ and BCY10 electrolyte on the other hand, were also characterised and area specific resistances of 0.06 Ω cm2 for the anode material and 1–2 Ω cm2 for the cathode material were obtained at 600 °C. 相似文献
83.
王远 《稀有金属材料与工程》2017,46(2):427-432
采用高真空电弧熔炼喷射成形法制备Zr_(47_x)Cu_(46)Al_7Y_x(x=3~8)大块非晶合金。采用X射线衍射分析、差示扫描量热仪、扫描电子显微镜、压缩试验和硬度试验分别研究Y含量对合金的非晶形成能力、显微组织、断口形貌及力学性能的影响。结果表明:Y含量对合金系的非晶形成能力和力学性能有显著影响,4 at%~7 at%Y含量试样由完全非晶组织构成,其过冷液相区ΔT_x为56~71 K,约化玻璃转变温度T_(rg)为0.665~0.678,但在3 at%与8 at%Y含量试样非晶基体中出现了极少量结晶组织。大块非晶具有较好力学性能,其抗压强度为1803~1899 MPa,维氏硬度为5.22~5.39 GPa,且具有较强非晶形成能力的试样相应地具有较好的力学性能。大块非晶在压缩中以纯弹性变形方式发生脆性断裂,断口光滑平整,为典型脉络状花纹。 相似文献
84.
Ahmed Jalal Samed Takayuki Tanaka Shin Hamada Keita Ikeue Masato Machida 《Catalysis communications》2009,10(15):1995-1999
Catalytic light-off of a stream of NO, H2, CO in an excess O2 has been studied over various metal oxides loading 1 wt% Pt. Because a low-surface area Y2O3 (<5 m2 g−1) was found to exhibit the highest de-NOx activity, a mesoporous Y2O3 was then synthesized from an yttrium-based surfactant mesophase templated by dodecyl sulfate , which was anion-exchanged by acetate (AcO = CH3COO−). The product showed a 3-D mesoporosity with a large surface area (396 m2 g−1) and the Pt-supported catalyst achieved much improved light-off characteristics suitable for the low-temperature de-NOx in the presence of CO and excess O2. 相似文献
85.
LiNi0.33−xMn0.33Co0.33YxO2 materials are synthesized by Y3+ substitute of Ni2+ to improve the cycling performance and rate capability. The influence of the Y3+ doping on the structure and electrochemical properties are investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and galvanostatic charge/discharge tests. LiNi0.33Mn0.33Co0.33O2 exhibits the capacity retentions of 89.9 and 87.8% at 2.0 and 4.0 C after 40 cycles, respectively. After doping, the capacity retentions of LiNi0.305Mn0.33Co0.33Y0.025O2 are increased to 97.2 and 95.9% at 2.0 and 4.0 C, respectively. The discharge capacity of LiNi0.305Mn0.33Co0.33Y0.025O2 at 5.0 C remains 75.7% of the discharge capacity at 0.2 C, while that of LiNi0.33Mn0.33Co0.33O2 is only 47.5%. EIS measurement indicates that LiNi0.305Mn0.33Co0.33Y0.025O2 electrode has the lower impedance value during cycling. It is considered that the higher capacity retention and superior rate capability of Y-doped samples can be ascribed to the reduced surface film resistance and charge transfer resistance of the electrode during cycling. 相似文献
86.
YAG纳米粉体的制备技术研究进展 总被引:9,自引:0,他引:9
近年来YAG纳米粉体因其具有特殊的性能而备受人们的关注。以此为原料采用先进的陶瓷制备工艺可以得到透明的YAG固体激光工作介质 ,其物理化学及光学性能可与单晶相比拟。YAG粉体通过掺杂Ce3 ,Tb3 ,Eu3 等离子还可以作为超短余辉荧光粉 ,在发光材料领域有广泛的应用。本文着重介绍了目前应用较多的几种YAG纳米粉体的制备方法 ,并简要地比较了各种方法的优劣。 相似文献
87.
《Ceramics International》2016,42(7):8263-8273
A machinable beta tricalcium phosphate [β-TCP, Ca3(PO4)2]-based composite has been produced by the classical ceramic sintering route by creating a weak interphase material of yttrium phosphate [YP, YPO4], from chemically synthesized and calcined β-TCP and up to 50 wt% YP powders. Sintered composites were characterized for phase constitution, densification and machinability (drilling) by using high-speed steel (HSS) and solid carbide (SC) drills in a conventional radial drilling machine. The effect of variation in drilling parameters (cutting speed and feed), cutting tool, batch composition on torque, thrust force and tool wear were studied. The biocompatibility of the sintered composites was also evaluated. It was found that with the increasing YP content the relative density of the composites decreased with an associated improvement in machinability with HSS and SC drills. Biocompatibility was also confirmed for the all the sintered composites. 相似文献
88.
H.B. Kim M.H. Cho S.W. Whangbo C.N. Whang S.C. Choi W.K. Choi J.H. Song S.O. Kim 《Thin solid films》1998,320(2):169-172
The heteroepitaxially grown yttrium oxide layer by an ionized cluster beam (ICB) on a Si(100) substrate was investigated by Rutherford backscattering spectrometry (RBS)/channeling. The channeling minimum value (χmin) of the Y2O3 layer on Si(100) is 0.28, and this is the smallest value among those reported. From the channeling polar plots, it is found that Y2O3 film grown on Si(100) oriented with (110) direction and has a double domain structure. The 110 axis of Y2O3 layer is exactly parallel to the 100 axis of the Si substrate. It is also observed that the interface region of Y2O3 film has more crystalline defects than the surface region. 相似文献
89.
90.
EffectofY_2BaCuO_5PhaseContentonMagneticPropertyinBulkMelttexturedYBCOFuXuekui(付雪奎),XiaoLing(肖玲),RenHongtao(任洪涛)(GeneralResear... 相似文献