Field-Assisted Sintering Technology / Spark Plasma Sintering

场辅助烧结技术/火花等离子烧结

• 批准号: 524821847
• 金额: --
• 依托单位: Rheinisch-Westfälische Technische Hochschule Aachen
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2023
• 资助国家: 德国
• 起止时间: 2022-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/524821847?language=en
• 关键词: Field; Assisted; Sintering; Technology; Spark

Field-Assisted Sintering Technology/Spark Plasma Sintering (FAST/SPS) is a unique technique for the synthesis and sintering of inorganic materials at high temperature that combines uniaxial pressure with a pulsed direct current. The voltage is low (below 10 V), but the current is high (typically from 1 to 10 kA), leading to efficient Joule heating as the current flows through the graphite dies where the inorganic powder is placed. These conditions allow to achieve heating rates up to 1000 K/min, although typically in the range 50 – 200 K/min, which are much higher than the heating rates (around 20 K/min) of other conventional sintering techniques such as pressureless sintering and hot pressing. The isothermal holding time is strongly reduced and just in a few minutes the sample is fully densified, meanwhile other techniques require several hours during the dwell time for the same purpose. Consequently, FAST/SPS leads to fully densify materials in just a few minutes, limiting – or even inhibiting - the grain growth and thus, tailoring the microstructure. Typically, graphite tools are used to contain the powders due to the high electrical and thermal conductivity as well as the high melting point (sintering up to approx. 2500 K). On the other hand, the graphite tools limit the maximal uniaxial pressure (typically up to 75 MPa) and require to use protective atmosphere such as vacuum or argon. Nevertheless, non-graphite tools are an alternative to increase the uniaxial pressure at expenses of reducing the maximal temperature. FAST/SPS is a versatile technique that leads to consolidate a manifold of materials, microstructures and structures. Metals and ceramics can be sintered, without any restriction due to their intrinsic electrical or thermal features, including intermetallics, superalloys, refractory metals, ultra-high temperature ceramics (UHTCs), transparent ceramics, carbides, nitrides, borides, oxides, MAX phases, and non-equilibrium materials. Importantly, synthesis can be also performed during the sintering process, which is called reactive sintering, developing fully dense compounds that cannot be produced by other methods. Furthermore, due to the characteristics of the heating conditions, the microstructure can be controlled to confer different properties. Regarding the structures, porous architectures with controlled porosity, bulk materials, ceramic matrix composites and joining of metals and ceramics can be obtained by FAST/SPS, avoiding the chemical reaction between different components due to the short thermal cycles (minutes instead hours).

现场辅助烧结技术/火花等离子体烧结（FAST/SPS）是一种在高温下无机材料合成和烧结的独特技术，将单轴压力与脉冲直流电流结合在一起。电压较低（低于10 V），但电流高（通常为1至10 ka），随着电流流过石墨死亡，放置了无机粉末，导致有效的焦耳加热。这些条件允许达到高达1000 K/min的加热速率，尽管通常在50-200 k/min的范围内，远高于其他常规烧结技术的加热速率（约20 k/min），例如压力无压烧结和热压力。等温固定时间大大减少，并且仅在几分钟内完全致密，而其他技术则需要在停留时间内几个小时才能实现相同的目的。因此，快速/SP会在短短几分钟内完全致密的材料，从而限制甚至抑制谷物的生长，从而定制微观结构。通常，由于高电导率和高熔点（大约2500 K），石墨工具用于包含粉末。另一方面，石墨工具限制了最大单轴压力（通常高达75 MPa），并需要使用受保护的气氛，例如真空或氩气。然而，非塑料工具是增加单轴压力，以降低最高温度的费用来增加单轴压力。 Fast/SPS是一种多功能技术，可巩固一系列的材料，微结构和结构。金属和陶瓷可以烧结，由于其内在的电气或热特征，包括金属固有的电气或热特征，包括金属，超合金，超级固有金属，超高温度陶瓷（UHTCS），透明的陶瓷，碳化物，碳化物，碳化物，氮化物，氮化物，硼化物，耐氧化物，氧化物，氧化物，氧化物，氧化物，最大相位和非平衡材料。重要的是，在烧结过程中也可以执行合成，该过程称为反应性烧结，开发完全致密的化合物，这些化合物无法通过其他方法产生。此外，由于加热条件的特征，可以将微结构控制到会议不同的特性。关于结构，可以通过快速/sps获得具有控制孔隙率，散装材料，陶瓷基质组件以及金属和陶瓷连接的多孔结构，避免由于短热循环而引起的不同组件之间的化学反应（而不是小时）。