Pre-activation of SBA-15 intermediate barriers with Pd nuclei to increase thermal and mechanical resistances of pore-plated Pd-membranes

Thermal and mechanical resistances of palladium composite membranes prepared by Electroless Pore-Plating (ELP-PP) and containing SBA-15 as intermediate layer were improved by doping the silica material with Pd nuclei before its incorporation on the composite membrane. Textural properties of synthesized SBA-15 materials (both raw and doped ones) were analyzed by XRD, N₂ adsorption-desorption at 77 K and TEM, while the main properties of the composite membrane were determined by SEM and gravimetric analyses. Moreover, membrane permeation tests were also carried out with pure gases, hydrogen and nitrogen, and binary mixtures of them at temperature of 400 °C and pressure driving forces in the range of 0.5–2.5 bar. The use of bare SBA-15 intermediate layer leads to the appearance of cracks on the Pd layer during permeation experiments at high temperature. In contrast, the use of Pd-doped SBA-15 particles avoids this problem, thus improving both thermal and mechanical resistances of the composite ELP-PP Pd-membrane. Following this preparation method, an estimated Pd thickness of 7.1 μm was obtained, reaching a hydrogen permeance of 3.81·10^?4 mol s^?1 m^?2 Pa^?0.5 and ensuring an ideal H₂/N₂ separation factor higher than 2550 at 400 °C.     

钻削GH4169高温合金薄壁件钻削力仿真研究

GH4169高温合金的薄壁钻孔与厚壁钻孔相比有特殊性,运用ABAQUS软件进行钻削GH4169高温合金薄壁件的仿真,研究钻削加工过程中钻削参数和工件厚度对钻削力的影响规律及变化特征,分析应力的分布规律。结果表明:钻削初期,横刃的挤压和主切削刃切削长度的增加使钻削力和扭矩增大;稳定钻削阶段,横刃切出后,主切削刃切削长度不变切削直径增加,钻削力和扭矩稳定增加;钻削后期,副切削刃参与切削,主切削刃切削长度减小,轴向钻削力和扭矩减小,但副刃与孔壁的挤压摩擦,曲线波动较大;钻削速度、进给量及工件厚度的增加都会导致轴向钻削力和扭矩的增加;钻削时的最大应力分布在横刃和主切削刃与工件的接触部位。     

Coating the porous Al2O3 substrate with a natural mineral of Nontronite-15A for fabrication of hydrogen-permeable palladium membranes

Substrate surface modification is a key pretreatment during fabrication of composite palladium membranes for hydrogen purification in hydrogen energy applications. The suspension of a natural porous material, Nontronite-15A mineral, without any organic additives was employed in dip-coating of the porous Al₂O₃ substrate. The Nontronite-15A mineral was characterized by SEM, XRD, TG−DSC and granulometry analysis. The surface and cross-section of the coated porous Al₂O₃ tubes were observed by SEM, and their pore size distribution and nitrogen flux were also measured. Palladium membranes were fabricated over the coated Al₂O₃ tubes by a suction-assisted electroless plating. The optimal loading amount of the Nontronite-15A mineral is just to fill in and level up the surface cavities of the Al₂O₃ substrate rather than to form an extra continuous layer. A thin and selective palladium membrane was successfully obtained, and its permeation performances were tested. The kinetic analyses on the hydrogen flux indicate that the hydrogen permeation behavior exhibits typical characteristics for most of the palladium membranes. During the stability test at 450 °C for 192 h, no membrane damage was detected, and the hydrogen flux increased slightly.     

全电动注塑机研究进展及在汽配电子行业中的应用

介绍了全电动注塑机的特色，综述了国内外全电动注塑机在精密注塑、智能注塑、高效注塑和绿色注塑方面的研究进展，并对全电动注塑机在汽配电子行业中的应用作了简单介绍。对双电机同步控制技术的逐渐成熟为全电动注塑机实现大型化提供了助力，全电动注塑机高效、精密、智能、节能、环保的优势在汽配电子行业显示了很好的应用前景。     

大型球磨机订购（制造）设计联络中零部件结构优化的探讨

针对大型球磨机使用中存在的问题，对球磨机主要零部件结构缺陷进行分析并提出解决方案。通过设计联络，提前对球磨机主要零部件结构进行优化，消除设备缺陷。大型球磨机设计联络中对主要零部件结构进行优化，对提高球磨机的运转率有着事半功倍的作用。     

空调复杂曲面钣金件的设计、分析及验证方法

本文讲述空调复杂空间曲面钣金件的设计思路及分析方法。主要从设计方法、模拟分析、零件测量比对等方面分析空间复杂曲面钣金件的设计思路,以满足结构使用要求、强度刚度以及经济要求。     

Enhancement of oxidation and wear resistance of Fe-based amorphous coatings by surface modification of feedstock powders

Surface oxidation of the in-flight powders during the preparation of amorphous coatings in high velocity oxygen fuel process causes the formation of oxygen-rich intersplat regions. These regions are brittle in nature and can dramatically deteriorate the mechanical performance of the coatings. To solve this problem, the starting FeCrMoCBY amorphous feedstock powders were modified by electroless plating a thin layer of Ni–W–P amorphous phase. It was found that the covering of the Ni–W–P layer can significantly reduce the oxygen content in the resultant Fe-based amorphous coatings. The wear resistance of the coatings with and without the modification of Ni–W–P thin layer was comparatively studied by ball-on-disk wear tests against Si₃N₄ counterpart in air. It revealed that the wear of two types of coatings follows the same oxidation wear mechanism but the modified coating exhibits much better wear resistance due to the improved oxidation resistance.     

耐火预制件在水泥窑中的应用

耐火预制件是将不定形耐火材料定形化，兼具有定形和不定形的优点。本文针对耐火预制件的特点以及在原料配比、形状设计等方面的要求，根据水泥窑不同部位的使用条件，分别介绍了篦冷机矮墙及顶部预制件、三次风管弯道预制件、三次风管闸板预制件、窑头罩预制件，为水泥窑用耐火材料的长寿化提供了方法，具有良好的应用前景。     

Microstructure and properties of open-cell Ni–Sn–P alloy foams prepared by electroless plating

In this study, open-cell Ni–Sn–P alloy foams were prepared by electroless plating. The influence of tin content on the surface morphology and properties of Ni–Sn–P alloy foams were investigated. The surface structure of Ni–Sn–P alloy foams became more uniform and compact with the increase of Sn content. The X-ray diffraction result showed that Ni–Sn–P alloy foams gradually transformed from an amorphous structure into crystallization with the increase of heat-treatment temperature. The introduction of Sn significantly enhanced the corrosion resistance of Ni–P coatings in 3.5 wt% NaCl solution, the corrosion current density decreased from 5.022 to 0.805 μA/cm² and the corrosion potential shifted positively from −0.423 to −0.294 V after adding 5.96 wt% Sn to Ni–P coatings. However, the corrosion resistance of Ni–Sn–P foams was deteriorated after heat treatment. Adding Sn to the Ni–P system slightly weakened the compressive strength of Ni–P binary foams. Nevertheless, significant improvement in the antioxidant performance of Ni–Sn–P alloy foams was indicated by the reduction of the mass change rate in that the mass change rate of Ni–P foams obviously reduced from 5.15% to 0.25% after adding 5.96 wt% Sn.     

低压冷喷涂Cu-Zn复合涂层耐蚀性能的研究

本文使用低压冷喷涂技术，分别在45#钢基体与45#钢加镀铬层基体上制备铜锌涂层试样。通过静态浸泡与铜加速醋酸盐雾腐蚀试验（CASS）对涂层和涂层加镀铬层试样的腐蚀性能进行研究；采用SEM、XPS对腐蚀前后涂层与镀铬层的微观形貌与元素进行表征。结果表明：静态腐蚀过程中，铜锌涂层的耐腐蚀性优于铜锌涂层加镀铬层；CASS实验中，随着原始粉体中锌含量的增加，涂层试样与涂层加镀铬层试样的耐腐蚀性能提高，当铜锌比为6:4时，对应涂层试样、涂层加镀铬层试样与纯镀铬层的耐腐性能达到六级。铜锌涂层在腐蚀液中由于电化学腐蚀及氯化作用，导致铜锌均发生了腐蚀，其腐蚀产物主要为Zn(OH)2、Cu2O与CuCl2。铜锌涂层加镀铬层试样在腐蚀过程中，锌的腐蚀在一定成上可以起到减缓镀铬层腐蚀的作用，这种减缓的作用与镀铬层上析出的铜膜共同保护镀铬层，增强其耐腐蚀性能。