The reinforcement role of different amino-functionalized multi-walled carbon nanotubes in epoxy nanocomposites

Functionalization with different amino groups of multi-walled carbon nanotubes was achieved and nanotube-reinforced epoxy nanocomposites were prepared by mixing amino-functionalized multi-walled carbon nanotubes with epoxy resin. Differential scanning calorimetry, thermogravimetric analysis and bending tests were used to investigate the thermal and mechanical properties of the nanocomposites. The results showed that different kinds of amino-functionalized multi-walled carbon nanotubes would have different effects on the thermal and mechanical properties of the nanocomposites. The reinforcement mechanism of amino-functionalized multi-walled carbon nanotubes in epoxy resin was discussed.     

Wet and dry tribological behaviors of circular islandic protrusion patterns on M2 steel discs under spinning condition

Under spinning conditions, lubricant on islandic spot patterned M2 steel disc experiences centrifugal and tangential force components. Depending upon the relative position of the spots and the flow of lubricant, accumulation of lubricant in front of patterned islandic spots creates thrusting to mating part and subsequently reduces contact between the mating couple. Whilst wear debris is likely to be spun off the plateau of the spots to their neighbouring valleys so as to reduce wear. Hence, it gives favorable tribological characteristics. Aiming at verifying such mechanisms, studies were performed on M2 steel disc specimens slid with ASSAB 17 tool steel pin. The M2 steel disc specimens were respectively （i） machined with non-patterned （NP）, （ii） etched to produce in-lined （INE） islandic patterns, and （iii） etched to produce staggered （STE） islandic spot patterns. Results indicated that the INE patterned discs gave most favorable wear characteristics, the NP of the worse characteristics whilst the STE ranged in the middle. However, the actual contact mechanism leads to the descending sequence of favorable friction behaviors nominally as： NP, INE and STE.     

铝合金在我国不同气候条件下的腐蚀行为及防腐蚀措施的研究现状

综述了铝合金大气腐蚀的机理和影响因素(化学组成、工艺、气象因素、环境因素),介绍了不同型号的铝合金在不同气候条件下的腐蚀行为(腐蚀形貌和腐蚀产物)以及防止铝合金大气腐蚀的防护措施(表面处理、防腐蚀涂料、聚合物防腐蚀膜)。     

Tribological behaviors of spot-textured TiN coatings on M2 high-speed steel under boundary lubricated conditions

The effect of sliding duration on the tribological behaviors of spot patterned coatings was investigated. Two patterns based on physical vapor deposition （PVD） TiN coatings were used, such as, in-lined （IN） and staggered （ST） spots. The tribological behaviors were evaluated by using a Cameron-Plint wear test rig. The M2 steel discs deposited TiN coatings with IN and ST patterns slid against the ASSAB 17 tool steel pins at a speed of 0.23 m/s, in Shell Tellus T32 lubricant and were loaded with 900 N. The testing results on disc specimens with two types of PVD TiN spot patterns, all coated with a bias voltage of-180 V and slid for 4, 8 and 11 h respectively, were presented. The results revealed that the in-lined coatings possessed relatively better wear behaviors than the staggered pattern coatings. Mechanisms for such superiority and for the cause of peeling were discussed. A relevant design approach was suggested for the application of such patterned coatings.     

WFLC-11钴基合金激光熔覆层组织及性能评价

对自主开发的WFLC-11激光熔覆专用钴基合金粉末激光熔覆层与Stellite-6合金等离子喷焊层的组织与性能进行了比较研究。结果表明，激光熔覆层组织细小、均匀，致密性好，高温硬度更高，其显微硬度、耐腐蚀性能、抗擦伤性能优于Sellite-6合金等离子喷焊层。     

38CrMoAlA钢大模数齿轮深层离子渗氮工艺探讨

对38CrMoAlA钢大模数齿轮进行了深层离子渗氮工艺试验,检测了离子渗氮层的组织和显微硬度分布.结果表明,38CrMoAlA钢大模数齿轮经深层离子渗氮后,其耐磨性显著提高.中碳合金钢大模数齿轮深层离子渗氮工艺或许将部分代替低碳合金钢气体大模数齿轮的渗碳、淬火工艺.     

低碳模式下的电泳涂装前处理技术

从低碳的模式出发,总结了传统电泳涂装前处理过程中,实现低能耗、低排放、低污染的技术原则和方法。介绍了新型转化膜技术的发展和应用情况,以及新型转化膜实际应用过程中亟待解决的问题。展望了涂装前处理技术的发展方向。     

镀钴碳纳米管的制备及其电磁特性

在碳纳米管表面镀覆磁性金属粒子,可获得电磁性能优异的复合材料.对碳纳米管进行预处理,再用化学镀法在其表面包覆钴金属制备碳纳米管-维复合材料.用透射电子显微镜(TEM)、能谱仪、振动样品磁强计、矢量网络分析仪分析了复合材料的形貌、成分及电磁性能,并研究了化学镀工艺对镀层沉积速率的影响.结果表明:镀覆后碳管表面包覆了一层钴...     

奥氏体不锈钢低温气体渗碳过程中温度对渗碳层的影响

利用扫描电镜、电子探针、显微硬度计、CS电化学工作站研究AISI316奥氏体不锈钢经低温气体渗碳处理后渗碳层显微组织及力学特性的变化。结果表明,在450,470,500℃温度条件下,在AISI316奥氏体不锈钢表面获得10~33μm的硬化层,随温度的不同,渗层深度、硬度梯度、耐蚀性能呈现不同的变化规律。     

奥氏体不锈钢镀铁、氟化前处理低温气体渗碳层性能比较与分析

提出了一种近年发展较快、兼顾表面强度与耐蚀性能的表面强化工艺——低温气体渗碳技术.选用电镀法、氟气处理法前处理工艺,利用低温气体渗碳技术对奥氏体不锈钢进行低渗碳处理,比较、分析2种预处理对渗碳层的影响.