报告题目：先进高温纳米制造 High temperature nanomanufacturing for emerging applications
报告人：姚永刚博士，美国马里兰大学
报告时间：2019年01月07日9:00-10:30
报告地点：卢嘉锡楼202室
报告摘要：
高温处理能够对材料的成分、结构及形貌变化提供了充足的能量和环境，因此普遍存在于各种反应、合成及后处理中。然而，传统的高温热源（比如炉子），因为其庞大的腔体以及缓慢冗长的加热方式(~1300 K, ~10 K/min)，使其不能很好的满足或应用于纳米材料的处理。此次报告中，我们将讨论如何利用电加热的方式做为一种新的高温合成与处理纳米材料的方法，从而推进快速纳米制造。
我们开发了易实现、非常稳定和可控的微纳米级加热的方式。超高温(>2500 K) 处理使得碳纳米材料高度结晶化，并且快速的加热 (~100 K/min) 使得纤维在交接的地方被‘焊接’起来，形成3维碳网络并且性能得到极大提升。同时，超快速超短时间加热(~2000 K in 55 ms)负载有前驱体盐的碳材料，可以原位形成极小且分布均匀的纳米颗粒。只需要简单的调节盐的成分，我们可以合成双元、三元、一直到8元的高熵纳米合金颗粒。这种高温合成与处理纳米材料的方式是简单、快速、节能并且可以规模化纳米制造。
High temperature processing can provide sufficient activation energy for materials’ compositional, structural, and morphological evolutions, and is essential for various kinds of reactions, synthesis, and post-treatment. However, the current high temperature heating sources, mostly furnaces, are far from satisfying for nanomaterials processing owing to their bulky size and limited temperature and ramp range (~1300 K, ~10 K/min).
In this talk, we will discuss using electrical triggered Joule heating as a new route for high temperature engineering of nanomaterials toward scalable nanomanufacturing. We developed facile, highly stable and controllable heating strategies for micro/nanoscale high temperature engineering. Ultrahigh temperature annealing (>2500 K) is applied to carbon nanomaterials for rapid graphitization with significantly improved crystallinity and importantly, the rapid heating (~100 K/min) leads to junction welding at junctions, forming 3D interconnected carbon with greatly enhanced properties. Ultrafast thermal shock (~2000 K in 55 ms) is applied to metal salt loaded carbon substrates for in-situ synthesis of ultrasmall, well-dispersed nanoparticles. By varying the composition in salt mixtures, we synthesized bimetallic, multimetallic and high entropy alloy nanoparticles (HEA-NPs) containing up to 8 different and immiscible elements. The high temperature engineering on nanomaterials are also highly facile, energy-efficient, and reliable toward scalable nanomanufacturing.
个人简介
姚永刚，西安交通大学材料物理专业本科及凝聚态物理专业硕士，美国马里兰大学材料科学与工程专业硕士/博士，现在美国马里兰大学从事博士后研究工作。主要研究方向在纳米材料的合成，性能提升及规模化制备的探索，尤其是开发出一种独特的超高温超快速方法用于高温纳米合成与制造（high temperature nanomanufacturing）。近五年在Science, Nature Energy, Energy Environmental Science等国际权威期刊共发表学术论文>80篇，他引>2500次。
