退火温度对IrO_2+ZrO_2涂层结构和电容性能的影响

采用热分解法在Ti基上被覆了IrO_2+ZrO_2氧化物涂层。通过XRD、SEM、EDX、XPS和循环伏安法等分析了退火温度对IrO_2-ZrO_2二元氧化物涂层的物相、表面形貌和电容性能的影响,引用非线性方程q~*(v)=A_1exp~(-v/t_1)+A_2exp~(-v/t_2)+y_0计算了涂层的内外活性点。结果表明:IrO_2-ZrO_2涂层的临界晶化温度为340~360℃,340℃退火的涂层物相为非晶结构,360℃退火,含有晶态和非晶态2种结构组织,其离子价态为Ir~(3+)、Ir~(4+)以及过饱和IrO_(2+x)(x0)。电容性能随着温度的升高呈先增大后减小变化,360℃退火的电极有最大的电容值,与其"非晶态/晶态"两相共存组织结构有关。涂层中质子迁移能力比电子导电能力对电容的影响要大,扫描速度对质子迁移的影响大于对电子导电的影响。     

Interfacial microstructure and properties of YG11C/42CrMo joint brazed with BCu64MnNi filler metal

Brazing hard alloy to high strength steel, incomplete atomic diffusion and excessive brittle reaction product precipitation at the faying interface are usually suffered because of incomplete understanding the process of the initial interface disappearing and diffusion layer forming and evolving. In this paper, hard alloy YG11C (WC-11wt.%Co) and high strength steel 42CrMo were picked up as base metals and BCu64MnNi as filler metal to clarify the interfacial microstructure evolution. The process parameters of dwell time were set as 30s, 60s, 120s, and 300s and braze temperature were set as 950℃, 970℃, 990℃, 1010℃, the effect of which on the evolution of interfacial microstructure, tensile strength, integrated with fracture morphology analysis, were conducted. The results showed that increasing brazing temperature from 950℃ to 970℃, no significant difference existed in the joint interface, whereas brazed at 990℃, the binder phase erosion occurred, i.e. the liquid filler metal etched into Co binder phase of WC-Co base metal, which caused WC particles debonding from the base metal surface and formed an micro-anisotropic zone.. Increase temperature to 1010℃, severe binder erosion happened so as to micropores appear. Through the parameters optimization, the tensile strength can reach to the maximum 589MPa at temperature of 970℃. The dwell time showed similar effect on tensile strength because longer dwell time also caused erosion and porosity owing to long-time diffusion and reaction.     

Research progress in electron transport layer in perovskite solar cells

Since perovskite solar cells appeared in 2009, its simple preparation process, high photoelectric conversion efficiency and the characteristic of low cost in preparation process let it become the hot spot of both at-home and abroad. Owing to the constant efforts of scientists, the conversion efficiency of perovskite solar cells is more than 20% now. Perovskite solar cells are mainly composed of conductive glass, electron transport layer and hole transport layer, perovskite layer and electrode parts. This paper will briefly introduce the working principle and working process about the electron transport layer of perovskite solar cells. The paper focuses on aspects such as material types(e.g., inorganic electron transport materials, organic small molecule electron transport materials, surface modified electron transport materials and doped electron transport materials), preparation technology of electron transport layer, the effects of electron transport layer on the photovoltaic performance of the devices, and the electron transport layer in the future research.     

Performance variability of Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ) cathode on proton-conducting electrolyte SOFCs with Ag and Au current collectors

Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)(BSCF) is one of the most active cathode materials and shows significant hydration effect suggesting possible proton conductivity.In this study,the performance of BSCF cathode on a protonconducting BaZr_(0.1)Ce_(0.7)Y_(0.2)O_(3-δ)(BZCY) electrolyte with silver and gold current collectors was determined.The electrochemical characteristics of the symmetrical and anode-supported cell with diluted silver electrode,silver current collector or gold current collector on BSCF electrode were compared.The significant result is that,although the diluted silver electrode itself shows poor operation stability,the silver current collector has strong electrocatalytic contribution to the BSCF cathode performance on the proton-conducting electrolyte,leading to higher cell performance than that with the gold current collector.     

直接喷墨打印成形铁磁软磁材料的工艺研究

本文以羰基铁粉为原料,用DISPER-Y220为分散剂,制备出粘度为0.55Pa.s,流动性良好的料浆,以此料浆作为打印“墨水”,利用直接喷墨打印成形技术制备纯铁软磁材料制件。喷头直径分别以0.5mm、0.8mm和1.0mm打印零件,打印成形后通过脱脂和烧结制备出制件。结果表明：分散添加量为1wt%时,料浆粘度最低,随着固含量的增大,料浆粘度变大,随着剪切速率的增大,料浆表现为剪切变稀特征;喷头直径为0.8mm所打印的烧结体,表面粗糙度最低,其Ra为0.8μm;在1300℃保温2h烧结后,喷头直径为0.5mm的烧结体致密度最高,为96.3%,其磁饱和感应强度B_s达到1.53T,最大磁导率μ_max达到2630。     

Ba(Mg1/3Ta2/3)O3热障涂层的制备及抗热震性能研究

本文以BaCO₃、MgO、Ta₂O₅为原料,采用固相反应法合成了Ba(Mg_1/3Ta_2/3)O₃(简称BMT)陶瓷粉末,利用大气等离子喷涂技术制备了BMT/YSZ双层陶瓷涂层。利用XRD、SEM和金相显微镜检测了BMT粉体及涂层的物相组成和显微结构。采用水淬法考核了涂层的抗热震性能。结果表明：1450℃下煅烧4h可合成出具有复合钙钛矿结构的BMT粉末,粉末具有良好的高温相结构稳定性。等离子喷涂制备的BMT/YSZ涂层组织致密,涂层系统中各界面结合紧密。涂层在室温至1150℃间热震9次后发生片状剥落,剥落位置位于BMT层间,BMT材料低的断裂韧性和第二相Ba₃Ta₅O₁₅的存在是导致涂层失效的主要原因。     

镧对Cu/Ti3SiC2/C/MWCNTs/Graphene/La纳米复合材料摩擦学性能的影响

本研究采用真空热压及热等静压方法制备Cu/Ti3SiC2/C/MWCNTs/Graphene/La纳米复合材料,采用摩擦磨损试验机研究对磨材料为GCr15时,镧含量对Cu/Ti3SiC2/C/MWCNTs/Graphene/La纳米复合材料的摩擦学性能的影响。研究了镧含量、正应力及旋转速度对纳米复合材料摩擦学行为的影响并揭示其相互作用机理,采用正交试验分析、方差分析及极差分析法来分析镧含量、正应力及旋转速度的相互作用。采用扫描电镜和能谱仪观察并分析磨损表面及磨削的形态及成分组分。研究结果表明镧对纳米复合材料的摩擦磨损性能起到首要作用,当镧的质量分数为0.05%时,复合材料的磨损机理为磨粒磨损、剥层磨损和氧化磨损,而当镧的质量分数为0.1%和0.3%时,复合材料的磨损机理为粘着磨损和氧化磨损。     

Insights into process–structure–property relationships of poly(ethylene terephthalate) industrial yarns by synchrotron radiation WAXD and SAXS

Synchrotron radiation wide angle X‐ray diffraction (WAXD) and small angle X‐ray scattering (SAXS) were performed to study the structures of four typical types of poly(ethylene terephthalate) (PET) industrial yarns. Three‐dimensional structural models of the yarns and comprehensive insights into the process–structure–property relationships were gained. High spinning speed, low draw ratio, and high heat‐setting temperatures lead to HMLS yarns with high crystallinity, high amorphous orientation, densely packed lamellar stacks, and a small tilting angle of crystalline lamellae. High draw ratio tends to result in PET industrial yarns with large long period and a large tilting angle of lamellae. Heat‐setting process has a significant influence on the amorphous orientation and crystalline structures, such as crystallinity, crystallite size, as well as crystal grain number. Compared with other structure characteristics, amorphous orientation plays a more important role in determining the tenacity, initial modulus, part load elongation, ultimate elongation, as well as shrinkage of PET industrial yarns. The crystal grain number seems to have an effect on the initial modulus, while the long period influences the elongation of the yarns to some extent. In addition, the small tilting angle of crystalline lamellae may relate to the dimensional stability of PET yarns. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42512.     

Aerogel of nitrate glycerol ether cellulose based on phase separation in acetone/ethanol mixed solvents system

Nitrate glycerol ether cellulose (NGEC) alcogels are formed in the ternary NGEC/acetone/ethanol system. NGEC aerogels are prepared from NGEC alcogels after solvent exchange and drying under supercritical CO₂ (scCO₂). The aerogels are prepared with various densities and porosities, relating directly to the initial ethanol content. NGEC aerogels had surface areas of up to 183 m² g^?1 and large mesopore volumes with a combination of large macropore volumes and a wide range of mesopore sizes. The aerogels with larger pore size distribution range, average pore diameter, and mesopore and macropore volume were obtained from system with higher ethanol content. The aerogels were further characterized by X‐ray diffraction, Brunauer–Emmett–Teller analysis, electron microscopy, and thermogravimetric analysis. The results showed that the NGEC aerogels clearly retained the crystalline structure from NGEC. Compared with NGEC powders, the thermal decomposition of NGEC aerogel is accelerated and this process becomes more acute. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41405.     

中国竹建筑工程2035发展趋势与路径研究

通过文献量化分析综述竹建筑工程在全球的发展情况及国内外50位专家的问卷调查和访谈结果,分析我国竹建筑工程发展过程中所面临的主要障碍,总结未来竹建筑工程的发展趋势。通过技术路线图研究竹建筑工程领域的关键技术与发展路径,指出面向2035我国竹建筑工程领域发展所需要的六项战略支撑与保障,包括提升企业规模和核心竞争力、建立国家重点实验室、设立专项科研基金、顶层设计技术标准体系、大力推广示范工程以及加强国际合作。