Polymer-derived Si3N4 nanofelts for flexible, high temperature, lightweight and easy-manufacturable super-thermal insulators. (September 2020)

• Record Type: Journal Article
• Authors: Biesuz, Mattia; Zera, Emanuele; Tomasi, Michele; Jana, Prasanta; Ersen, Ovidiu; Baaziz, Walid; Lindemann, André; Sorarù, Gian Domenico
• Is Part Of: Applied materials today. Volume 20(2020)
• Publication Date: 2020-09
• Subjects: Si3N4 -- Polymer-derived ceramics -- Ceramic fibers -- Thermal insulators -- Ceramic felts; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2020.100648
• Languages: English
• ISSNs: 2352-9407

Abstract

Highlights: A novel simple synthesis route to Si3N4 nanofelts has been developed. The nanofelts can be easily shaped in large and complex componenets. The thermal conductivity of the nanofelts is as low as 11 mW m −1 K −1 in Ar. The thermal stability of the nanofelts is excellent up to 1000°C in air. Flexible nanofelts can be obtained. Abstract: Nowadays, the best thermal insulators are aerogel-based materials. However, their industrial application is constrained by a complex synthesis route (requiring supercritical drying) and by their fragility. Moreover, the most common aerogels, based on amorphous SiO2, have a poor thermal stability. In this work, a fast and simple synthesis route to ultra-highly-insulating Si3 N4 nanofelts is developed. The process is based on a specific treatment of SiOC polymer-derived ceramics in N2 atmosphere. The obtained nanofelts possess porosity as high as 99.7% (10 kg m −3 ) and thermal conductivity down to 11 mW m −1 K −1 in Ar atmosphere, which is among the lowest ever measured. The new material surpasses aerogels in terms of flexibility and temperature resistance. Moreover, it can be easily shaped in physical objects of industrial interest. Thus, it offers a unique combination of intriguing properties such as thermal insulation, lightweight, temperature resistance and flexibility. These, combined with the simple manufacturing process, could lead to far-reaching implications in multiple technological fields. Graphical abstract: Image, graphical abstract