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This letter presents in detail a new process for the fabrication of 3D stainless steel microcomponents using cold-isopressing techniques. The process starts by producing deep SU-8 master moulds and their negative soft micromoulds in polydimethylsiloxane (PDMS), preparing stainless steel semi-solid paste with high solid loading, filling the soft micromoulds, covering the filled moulds and putting them under hydrostatic pressure. After the pressure is released the green microparts are obtained, de-bound and sintered in vacuum at 1350degC. The resultant microparts show the same quality as the SU-8 master moulds without deformation. The effect of applied hydrostatic pressure on the density of the green and sintered parts as well as the linear shrinkage is discussed in detail. The maximum density of the sintered parts and its corresponding linear shrinkage are found to be 98.6 and 13deg, respectively. 相似文献
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A fabrication process of 316-L stainless steel microcomponents and characterisation of their surface roughness and porosity is presented. The fabrication process is divided into two parts. In the first part, SU-8 master moulds and their negative replicas from soft moulds are fabricated using photolithography and soft moulding techniques, respectively. The second part includes preparing stainless steel slurry using super fine stainless steel powder and binder, filling the soft moulds, obtaining the green parts, de-binding and sintering to the final parts. The resultant microparts reflect the same quality as the SU-8 master moulds. The surface roughness and porosity of the microparts are investigated using stereo imaging technique and X-ray microtomography, respectively. The average surface roughness Ra measures 132.2 nm and the overall porosity is found to be 4.5 . 相似文献
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激光选区烧结成形(SLS)技术是自下而上通过添加材料来成形的加成技术,它是不同于传统的自上而下的材料去除方式的机械加工方法.然而目前还没有一种将材料去除与加成相结合的激光加工成形技术.在研究激光与粉末材料相互作用时观察到粉末材料被气化的同时,激光光束周围的粉末被烧结的现象,利用这一现象探讨了激光气化烧结成形(LVS)的新方法,它既利用激光将粉末材料气化去除,同时又利用激光将粉末烧结加成在一起,形成所需的形状.该技术在制备、成形微型薄壁件时有独特的优势,薄壁的厚度由数个粉末颗粒组成,有望在激光烧结粉末微成形领域得到广泛应用. 相似文献
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为了实现不锈钢微细电解定域加工,提出激光掩膜表面改性微细电解复合加工技术。研发了激光掩膜微细电解复合加工装置,并进行样件加工试验。首先,采用光纤激光在304不锈钢表面扫描加热进行打标图案,利用X射线光电子能谱分析(XPS)对不锈钢表面激光打标图案进行分析,发现激光在不锈钢表面打标时被空气氧化生成铁、铬等氧化物,生成的打标图案具有耐腐蚀性,形成保护性掩膜。然后进行电解加工,由于掩膜图案在电解过程中起到保护作用,选择合适的电解加工参数,在不锈钢表面能加工复杂的微结构。最后利用SEM、光学轮廓仪来观测微结构形貌、粗糙度等。研究结果表明:利用激光表面改性,结合微细电解加工能实现304不锈钢微结构的快速加工,该工艺在微细加工领域具有很好的发展前景。 相似文献
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微纳米尺度的表面结构在表面工程中有着许多特殊的性能和应用,为了研究飞秒激光制备不锈钢表面微纳结构的机理,基于经典双温模型理论对飞秒激光烧蚀304不锈钢的过程进行了数值模拟计算。经过计算得到了不同激光能量密度、不同烧蚀深度处电子与晶格系统温度的演化规律,确定了飞秒激光单脉冲作用下的烧蚀阈值,通过数值模拟得到飞秒激光烧蚀不锈钢只发生在材料的表面,对内部的材料影响很小。最后使用飞秒激光微纳加工系统在不锈钢表面制备了微纳结构,多边形微孔结构保持了高质量的边缘形貌,在孔的内壁出现了周期性结构。 相似文献
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Traditional materials used in chip-level interconnections are not compatible with the high-temperature operation of wide-bandgap
high-power semiconductor devices; therefore, this paper studies sintered nano-silver as a novel interconnect material mounting
semiconductor devices onto metallized substrates. A low-temperature sintering process was employed in the preparation of a
sintered nano-silver die-attachment. The physical mechanisms in volatilization and burnout of the added organic components
employed in nano-silver paste were analyzed primarily by thermal gravimetric analysis (TGA) to obtain a reasonable temperature-controlling
profile. The shear strength of sintered nano-silver joints was investigated, and the evolution of microstructure in the nano-silver
paste sintering process was observed using a scanning electron microscope (SEM) in this process. The effects of sintering
temperature, heating rate, and holding time during the sintering process were analyzed according to the densification mechanism.
The microstructural observations and shear strength tests showed that a sintering temperature of 285°C, heating rate of 10°C/min,
and holding time of 60 min were the best conditions for using this kind of silver paste. 相似文献
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为了通过选区激光熔化技术直接快速成型高致密度及高表面质量零件,采用正交试验对316L不锈钢粉末进行了光纤激光选区熔化成型研究,分析了正交实验中存在的扫描线间搭接缺陷及零件外边凸起缺陷,随后“层间错开”扫描策略因为更好的扫描线间润湿效果及成型效率而被应用于实验中,进行扫描线间搭接情况及层间熔接情况显微观察。层间层内扫描线具有良好的冶金结合,孔隙率大大减少,获得了高致密化的成型效果;使用优化的工艺参量与扫描策略成型具有空间曲面的个性化手术模板,硬度与致密度分别达HV0.3250和95.8%。结果表明,层间扫描策略对选区激光熔化技术直接成型金属零件成型效果良好。 相似文献
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不锈钢半球引伸,因其强度大、硬度高和不易压边,引伸时极易起皱,成形质量差。通过对不锈钢零件材料性能和引伸成形工艺分析,确定了合理的成形工艺方案,设计了在液压机上成形半球形零件的引伸模,有效地防止了零件的起皱,提高了合格率,解决了高强度不锈钢半球引伸成形的难题。 相似文献
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瓷粉粒度和形貌对成瓷性能的影响 总被引:4,自引:0,他引:4
瓷粉的颗粒度分布和颗粒的形貌是瓷粉的重要特性。它们对流延的生瓷片性能、烧成后晶粒尺寸、熟瓷的致密性、熟瓷的强度、烧结温度以及烧结时x ,y,z方向的收缩率等均会产生重要的影响。本文主要介绍这些特性产生的机理和影响程度。 相似文献
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Howell R.S. Stewart M. Kamik S.V. Saha S.K. Hatalis M.K. 《Electron Device Letters, IEEE》2000,21(2):70-72
We report the successful fabrication of poly-Si thin-film transistors (TFTs) on stainless steel substrates. The TFTs were fabricated on a 500 μm thick polished stainless steel substrate using furnace crystallized amorphous Si deposited by PECVD. These devices typically have threshold voltages of 8.6 V, linear effective mobilities of 6.2 cm2/V·s and subthreshold slopes of 0.93 decade/V. This work demonstrates the feasibility of poly-Si TFTs on stainless steel substrates and identifies some critical issues involved in poly Si processing on stainless steel. This will enable the fabrication of arrays with integrated drivers on a cheap, flexible and durable substrate for various displays and other large area array microelectronic applications 相似文献