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可加工烧结氧化锆陶瓷的制备

Making sintered zirconia ceramics machinable
课程网址: http://videolectures.net/ipssc2017_lazar_zirconia_ceramics/  
主讲教师: Ana Lazar
开课单位: 国家生物研究所
开课时间: 2017-05-23
课程语种: 英语
中文简介:
基于氧化锆的先进陶瓷材料由于其高强度和高韧性,非常适合不同的结构应用。烧结氧化锆陶瓷的加工仅限于昂贵、耗时且仅限于简单几何复杂性的金刚石工具。电火花加工(EDM)可以克服金刚石工具加工的局限性,但是,它只能在具有足够导电性的导电陶瓷(ECC)上进行。这通常是通过将导电(EC)相并入绝缘陶瓷基体来实现的。 到目前为止,已经通过混合商业粉末、其固结和烧结制备了含有各种EC相的氧化锆基ECC,例如TiC、TiCN、WC、ZrB2、TiN、碳纳米管(CNT)和/或石墨烯。然而,获得均匀的微观结构是一个有待克服的挑战。如果EC和陶瓷基体相的粒度在同一范围内,电火花加工所需的导电性在EC相含量较高(>30 vol.%)时达到,这可能由于微观结构的不均匀性而对机械性能有害。另一方面,当EC相的颗粒在纳米尺度范围内和/或非极性(如CNT和石墨烯)时,它们容易团聚,并且难以均匀分散在水悬浮液中。 在这里,将介绍几种替代的、新颖的加工方法,基于水胶体加工与火花等离子烧结炉中的快速固结相结合,提供均匀、高导电、EDM可加工的氧化锆陶瓷复合材料。
课程简介: Advanced ceramic materials based on zirconia are very suitable for different structural applications owing to its high strength and toughness. Machining of sintered zirconia ceramics is limited to diamond tools that is expensive, time consuming and limited to simple geometrical complexities. Electrical discharge machining (EDM) can overcome the limitations of machining with diamond tools, however, it can only be performed on electro-conductive ceramics (ECC) exhibiting sufficient conductivity. This is usually achieved by incorporation of electro-conductive (EC) phase into the insulative ceramic matrix. Up to now zirconia-based ECC containing various EC phases, such as, TiC, TiCN, WC, ZrB2, TiN, carbon nanotubes (CNT) and/or graphene, have been prepared by mixing of commercial powders, their consolidation and sintering. Attaining homogeneous microstructures, however, is a challenge yet to be overcome. In case the particle size of both EC and ceramic matrix phase is in the same range, the electrical conductivity required for EDM is attained at high content of EC phase (>30 vol. %), which can be detrimental for mechanical properties as a result of microstructural inhomogeneities. On the other hand, when the particles of EC phase are in the nanoscale range and/or nonpolar (as CNT and graphene are), they are prone to agglomeration and are difficult to homogenously disperse in aqueous suspensions. Here several alternative, novel processing approaches, based on aqueous colloidal processing combined with rapid consolidation in the Spark plasma sintering furnace, will be presented, providing homogenous, highly electro-conducting, EDM machinable zirconia ceramic composites.
关 键 词: 先进陶瓷材料; 结构应用; 烧结氧化锆陶瓷
课程来源: 视频讲座网
数据采集: 2021-11-05:zkj
最后编审: 2021-11-05:zkj
阅读次数: 69