Effect of Y2O3 on acid resistance of alumina ceramic

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.     

Intermediate Temperature Anode‐Supported Fuel Cell Based on BaCe0.9Y0.1O3 Electrolyte with Novel Pr2NiO4 Cathode

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 Pr₂NiO_{4 + 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.     

Y含量对Zr_(47-x)Cu_(46)Al_7Y_x合金非晶形成能力及力学性能的影响

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。     

Catalytic NO–H2–CO–O2 reactions over Pt-supported mesoporous yttrium oxide

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-NO_x 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-NO_x in the presence of CO and excess O₂.     

Characterization of yttrium substituted LiNi0.33Mn0.33Co0.33O2 cathode material for lithium secondary cells

LiNi_0.33−xMn_0.33Co_0.33Y_xO₂ 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. LiNi_0.33Mn_0.33Co_0.33O₂ 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 LiNi_0.305Mn_0.33Co_0.33Y_0.025O₂ are increased to 97.2 and 95.9% at 2.0 and 4.0 C, respectively. The discharge capacity of LiNi_0.305Mn_0.33Co_0.33Y_0.025O₂ at 5.0 C remains 75.7% of the discharge capacity at 0.2 C, while that of LiNi_0.33Mn_0.33Co_0.33O₂ is only 47.5%. EIS measurement indicates that LiNi_0.305Mn_0.33Co_0.33Y_0.025O₂ 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.     

YAG纳米粉体的制备技术研究进展

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。     

Biocompatibility and drilling performance of beta tricalcium phosphate: Yttrium phosphate bioceramic composite

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.     

RBS/channeling studies on the heteroepitaxially grown Y2O3 film on Si(100)

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 (χ_min) 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.     

水杨基荧光酮光度法测定钇

提出了在十八烷基二甲基苄基氯化段存在下,用水杨基荧光酮（ＳＦ）光度法测定钇,在ｐＨ７．５０缓冲溶液中Ｙ（Ⅲ）与ＳＦ形成络合物,其最大吸收位于５５５ｎｍ,摩尔吸光系数ε＝１．４０×１０￣５,服从比尔定律范围为０～８μｇ／２５ｍｌ。本文还对ｐＨ、试剂浓度、温度影响和外来离子干扰等因素进行了详细研究,该法已用于地质样中痕量钇的测定,结果满意。     

Effect of Y_2BaCuO_5 Phase Content on Magnetic Property in Bulk Melt－textured YBCO

ＥｆｆｅｃｔｏｆＹ_２ＢａＣｕＯ_５ＰｈａｓｅＣｏｎｔｅｎｔｏｎＭａｇｎｅｔｉｃＰｒｏｐｅｒｔｙｉｎＢｕｌｋＭｅｌｔｔｅｘｔｕｒｅｄＹＢＣＯＦｕＸｕｅｋｕｉ（付雪奎），ＸｉａｏＬｉｎｇ（肖玲），ＲｅｎＨｏｎｇｔａｏ（任洪涛）（ＧｅｎｅｒａｌＲｅｓｅａｒ...