Flash Sintering of SiC, Boron Carbide and Boron Carbide/SiC composites

背景和影响。陶瓷的快速烧结最早是由phalitis na等人在2010年报道的。与传统的烧结相比，新的方面是在加热的同时向样品施加额外的电场，在传统的烧结中，粉末压块在炉中加热。主要特征是（i）与常规烧结相比，烧结非常迅速（几秒cf.几个小时-加速约3个数量级）和（ii）烧结在比传统烧结中使用的炉温低几百摄氏度的炉温下进行（尽管由于焦耳加热，样品本身的温度更接近传统烧结温度）。通过更快的周转、更低的能耗（更少的加热）和更便宜的资本设备（更低的炉温）降低成本的影响是显而易见的。能量消耗的减少也使得加工更环保，并且也可以制造新的几何形状和结构以及提供改进的性能的新的微结构。这里的主要新奇之处是将这些技术应用于非氧化物，这需要比迄今为止大多数工作都在其上完成的氧化物高得多的加工温度。上述关于成本和环境影响的影响预计将在这些材料中得到放大。1.将闪速烧结可应用的非氧化物陶瓷的范围从SiC扩展到碳化硼和碳化硼/SiC复合材料.开发利用闪速烧结现象的新方法，通过使用新型电极系统生产更广泛的非氧化物陶瓷部件几何形状。3.研究和理解非氧化物快速烧结的基本机理，包括电响应和快速致密化的原因.测量所生产材料的性能，并确定闪速烧结非氧化物陶瓷在提高性能、降低成本和能源使用方面的潜在优势。方法的新奇性。迄今为止，几乎所有已发表的关于快速烧结的研究都是关于氧化物陶瓷的。已发表的关于SiC的工作具有非常初步的性质。关于碳化硼的文献更少。因此，主要的新奇将是在加工和烧结方法、机械理解和表征方面将这些材料的闪速烧结置于更坚实的基础上。目前的项目是从目前的EPSRC CASE项目与Dstl，其中基本设备和方法的快速烧结非氧化物的样品温度超过2000摄氏度的挑战性任务已经成立。几乎所有关于快速烧结非氧化物的加工、微观结构和性能的信息都将是新颖的。符合EPSRC的战略和研究领域。该项目与EPSRC产品组合的未来制造主题最紧密地结合在一起。然而，它也与能源，环境变化和工程主题有很强的联系。公司与合作。在这个项目中没有正式的合作。然而，相关的工作得到了Dstl和Morgan Advanced Ceramics的支持，并打算在整个项目中非正式地保持这些合作。此外，多年来一直与中小型企业Lucideon就闪速烧结的商业开发的可能途径保持对话和合作，这些对话和合作也将继续下去，以便对本项目的产出进行技术转让。

Context and impact. Flash sintering of ceramics was first reported by Cologna et al. in 2010. The novel aspect compared with traditional sintering, in which a powder compact is heated in a furnace, is the additional application of an electric field to the sample whilst heating. The main features are that (i) sintering is very rapid compared with conventional sintering (a few seconds cf. several hours - an acceleration of about 3 orders of magnitude) and (ii) sintering takes place at furnace temperatures several hundred Celsius lower than those used in conventional sintering (although the temperature of the specimen itself is closer to conventional sintering temperatures because of Joule heating). The impact of reduced cost through faster turnaround, lower energy consumption (less heating) and cheaper capital equipment (lower furnace temperature) is immediately apparent. The reduction in energy consumption also makes the processing more environmentally friendly and it may also be the case that new geometries and structures, and new microstructures giving improved properties can be manufactured. The chief novelty here is to apply the techniques to non-oxides, which need much higher processing temperatures than the oxides on which most work has been done to date. The above impacts concerning cost and environmental impact are expected to be amplified in such materials.Aims and Objectives. 1. To extend the range of non-oxide ceramics to which flash sintering can be applied beyond SiC to Boron Carbide and Boron Carbide/SiC composites.2. Develop new methods of harnessing the flash sintering phenomenon for the production of a wider range of geometries of non-oxide ceramic components by using novel electrode systems.3. To investigate and understand the fundamental mechanisms involved in flash sintering of non-oxides, including the electrical response and the reasons for the rapid densification observed.4. To measure the properties of the materials produced and to establish the potential advantages of flash sintering for non-oxide ceramics in terms of improvements in performance and reductions in cost and energy usage.Novelty of approach. Almost all published research on flash sintering to date has been on oxide ceramics. Published work on SiC has been of a very preliminary nature. There is even less in the literature on Boron Carbide. The primary novelty will therefore be to put flash sintering of these materials on a firmer footing in terms of the processing and sintering methods, mechanistic understanding and characterisation. The current project follows on from a current EPSRC CASE project with Dstl in which basic equipment and methods for the challenging task of flash sintering non-oxides with specimen temperatures of over 2000 Celsius has been set up. Almost all of the information on processing, microstructure and properties of flash sintered non-oxides to come out of the project will be novel. Alignment to EPSRC's strategies and research areas. The project aligns most closely with the Manufacturing the Future theme of the EPSRC portfolio. However, it also has strong links with the Energy, Living with Environmental Change, and Engineering themes. Companies and collaborations. There are no formal collaborations within this project . However, related work has been supported by Dstl and Morgan Advanced Ceramics and it is intended to maintain these collaborations informally throughout this project. In addition, dialogue and collaboration concerning possible routes to commercial exploitation of flash sintering have been maintained with the SME Lucideon for a number of years and these will also be continued with a view to technological transfer of the outputs from the present project.