退火温度对直流磁控溅射制备Ru薄膜微观结构及膜基结合力的影响

采用磁控溅射法在Mo衬底上制备了Ru薄膜,利用真空退火炉、EDS、XRD,台阶仪及纳米划痕仪等设备研究了不同退火温度对Ru薄膜化学成分、相结构、残余应力及膜基结合力的影响。结果表明,不同退火温度处理下的Ru薄膜呈六方Ru结构,具有（002）择优取向,当退火温度为600 ℃时,薄膜出现氧化相。退火处理能够改善薄膜结晶程度。随退火温度的升高,薄膜残余应力逐渐降低,膜基结合力先升高后降低,当退火温度为300 ℃时,膜基结合力最高,约为17.6 N。     

尼龙6共混改性研究进展

系统介绍了国内外用聚乙烯、聚丙烯、PVDF、PAR、PET、PVOH、ABS、PC、PPO、SAN、弹性体、TLCP等改性尼龙 6的系列方法、研究成果及其性能 ,并提出了反应挤出共混改性和无机纳米材料改性尼龙 6的设想     

Dispersions of carbon nanotubes in sulfonated poly[bis(benzimidazobenzisoquinolinones)] and their proton-conducting composite membranes

A sulfonated poly[bis(benzimidazobenzisoquinolinones)] (SPBIBI) possessing a conjugated pyridinone ring was shown to be effective for dispersing multiwalled carbon nanotubes (MWCNTs) in DMSO. The dispersions in which the SPBIBI to MWCNTs mass ratio was 4:1 demonstrated the highest MWCNTs concentrations, i.e., 1.5-2.0 mg mL⁻¹, and were found to be stable for more than six months at room temperature. Through casting of these dispersions, MWCNTs/SPBIBI composite membranes were successfully fabricated on substrates as proton exchange membranes for fuel cell applications and showed no signs of macroscopic aggregation. The properties of composite membranes were investigated, and it was found that the homogeneous dispersion of the MWCNTs in the SPBIBI matrix altered the morphology structures of the composite membranes, which lead to the formation of more regular and smaller cluster-like ion domains. As a result, and in comparison to a pristine SPBIBI membrane, the composite membranes displayed more significant proton conductivities, especially at low relative humidity, without sacrificing other excellent properties, such as thermal, dimensional and oxidative stabilities. For instance, the composite membranes with an MWCNTs content only of 0.5 wt% exhibited proton conductivities of 0.021 S cm⁻¹ at 50 RH% and 70 °C, a value almost fourfold as high as that of the pristine SPBIBI membranes under identical conditions (0.005 S cm⁻¹). The result was comparable to Nafion 117 (0.021 S cm⁻¹). The homogenous dispersion of the MWCNTs and the efficient enhancement the SPBIBI performance were attributed to the π-π interaction between the pyridinone ring and the sidewalls of the MWCNTs which changed the morphological structure of composite membranes as revealed by TEM. A combination of a low methanol crossover with excellent thermo-oxidative and water stabilities indicated that the SPBIBI composite membranes were good candidate materials for proton exchange membranes in fuel cell applications.     

CeO2 Nanocrystalline-Supported Palladium Chloride: An Effective Catalyst for Selective Oxidation of Alcohols by Oxygen

The present paper reports on the use of CeO₂ materials supported palladium chloride catalyst for selectively oxidising organic alcohols into aldehydes. Spherical, microsized rod-shaped and spindle-like CeO₂ particles are synthesised and characterised by SEM. The catalysts are prepared by loading palladium chloride onto the CeO₂ support matrix. A complete characterization of the catalysts is performed. The activity of catalysts is studied by the selective oxidation of various alcohols. The results show that (1) the catalytic activities prepared by spherical cerium are superior to the catalysts prepared by spindle-like or rod-shaped cerium and (2) the catalyst PdCl₂/CeO₂ (nanospheres) show good activity, high yield, and good stability.     

装备维修用带锈底漆的筛选

通过温度试验、盐雾试验、交变湿热试验和耐腐蚀试验考察了4种带锈底漆分别与S04-60面漆组成的涂层体系在简单处理后的铁锈板和铝锈板上的性能。试验结果表明,H53-32环氧带锈防锈底漆和S04-60丙烯酸聚氨酯面漆配套性良好,其涂层体系在两种基材上的初始附着力均为2级,高温贮存、低温贮存、温度冲击、盐雾试验后外观及附着力均无明显变化,交变湿热试验后外观完好,铁板附着力3级,铝板附着力2级,耐腐蚀试验时间均超过720 h,综合性能最佳,可以用作装备维修时的铁基材和铝基材的防护底漆。     

喷射成形7075铝合金欠时效回归再时效热处理

采用透射电镜、拉伸测试等方法,研究欠时效回归再时效处理对喷射成形7075铝合金显微组织和力学性能的影响,并与单级峰值时效和常规回归再时效处理相比较。结果表明,采用120℃×12h欠时效预处理比120℃×24h峰值时效预处理更有利于在回归处理后合金晶内析出相的回溶,回归处理过程可使合金晶界析出相充分断开,再时效后晶内的析出相细小弥散,合金抗拉强度和屈服强度分别为776和723MPa,均高于T6峰值时效和常规回归再时效水平。     

选区激光熔化Al-Mg-Sc-Zr合金成形性及力学性能研究

通过选区激光熔化(SLM)技术制备Al-Mg-Sc-Zr铝合金,系统研究了不同工艺参数对铝合金粉末成形性以及不同时效处理条件对SLM成形样品组织和力学性能的影响。结果表明,在高激光功率和低激光扫描速度下,SLM成形样品的致密度较高。沿样品沉积方向可观察到熔池层层堆叠的显微组织,熔池边界和熔池内部均存在细小纳米颗粒。经不同温度时效处理后,样品的硬度和压缩屈服强度先增加后降低。SLM成形样品经400℃时效处理3 h后屈服强度达到最大值469±4 MPa。     

Effects of silane grafting on the morphology and thermal stability of poly(ethylene terephthalate)/clay nanocomposites

An alkylammonium intercalated montmorillonite (A‐MMT) was modified by edge grafting with 3‐glycidoxypropyltrimethoxysilane. In comparison with poly(ethylene terephthalate) (PET)/A‐MMT, the resultant grafted clay, S‐A‐MMT, exhibited improved miscibility with PET matrix and revealed better dispersion state in the melting compounded PET/S‐A‐MMT nanocomposites. As a result, the PET/S‐A‐MMT nanocomposite had slower degradation rate owing to the enhanced clay barrier effect. Meanwhile, the nanocomposite exhibited lower degradation onset temperature under nitrogen because of the clay catalysis effect, which can be explained by the decreasing degradation reaction energy calculated from Coats–Redfern method of degradation kinetics. In the other hand, nanocomposite with better clay dispersion state exhibited increasing thermal oxidative stability due to clay barrier effect of hindering oxygen to diffuse in, which accorded with the continuous and compact char surface formed during polymer degradation. The clay catalysis and barrier effect of silicate layers were presented directly in isothermal oxidative TGA experiment. Furthermore, the mechanical and crystallization properties of PET/clay nanocomposites were investigated as well. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

空间机构移动副间隙的随机特性分析

在进行运动副间隙的随机特性分析时，应根据运动副受力情况的不同而采用不同的分析模型，运动副受力较小时可以采用随机模型，而当运动副受力较大时就应该采用连续接触模型，本文以移动副为例，分别用随机模型和连续接触模型对空间机构中运动副间隙的随机特性做了详细的分析，分析结果可在进行空间机构运动精度分析时作为理论基础。     

晶粒拓扑学的实验和仿真研究

采用系列截面法获取了纯铁晶粒组织的拓扑学数据,同时结合正常晶粒长大的Monte Carlo仿真,对三维晶粒拓扑学进行了研究。结果表明:纯铁的平均晶粒面数