Ultrarapid Multimode Microwave Synthesis of Nano/Submicron β-SiC

Min Zhao,Guangming Li,Chen Zhao,Michael Johnson,Luling Yu,Haochen Zhu,Wenzhi He,Juwen Huang

doi:10.3390/ma11020317

Abstract

This paper presents the design, development and realization of a fast and novel process for the synthesis of 3C silicon carbide (β-SiC) nanorods and submicron powder. Using SiO2 (or Si) and activated carbon (AC), this process allows β-SiC to be synthesized with almost 100% purity in timeframes of seconds or minutes using multimode microwave rotary tube reactors under open-air conditions. The synthesis temperature used was 1460 ± 50 °C for Si + AC and 1660 ± 50 °C for SiO2 + AC. The shortest β-SiC synthesis time achieved was about 20 s for Si + AC and 100 s for SiO2 + AC. This novel synthesis method allows for scaled-up flow processes in the rapid industrial-scale production of β-SiC, having advantages of time/energy saving and carbon dioxide emission reduction over comparable modern processes.

Highlights

In the material manufacturing sector, energy efficiency, sustainability and economic viability have become increasing important to the industry and society [1]
The prototype rectangular multimode microwave cavity (RMMC) rotary reactor used in this research was modified from a microwave oven with an alundum/quartz tube which was installed in the centre of the microwave oven, such that the tube could be rotated by a motor drive
Β-silicon carbide (SiC) powder was successfully synthesized in minutes using the RMMC rotary reactor and in seconds using the newly developed cylindrical multimode microwave cavity (CMMC) rotary reactor

Summary

Introduction

In the material manufacturing sector, energy efficiency, sustainability and economic viability have become increasing important to the industry and society [1]. For the microwave device design and manufacturing, a rectangular multimode microwave cavity (RMMC) rotary reactor (e.g., a domestic microwave oven with improvements) was used for preliminary research and exploration Using this platform, β-SiC synthesis was improved in line with industrial application requirements. An improved cylindrical multimode microwave cavity (CMMC) rotary reactor was designed and fabricated This CMMC reactor had a higher microwave power rating than the RMMC reactor, facilitating greater time/energy savings. This “tunnel style” reactor allows production efficiency to be greatly improved, and enables the design of scaled-up flow processes using this device. “Tunnel style” microwave reactors can be used individually or in series as required, with the internal SiC production materials being laid out on a removable refractory material and the production materials moving though the production process

Materials and Devices

Characterisation

Results and Discussion

SEM micrographs of Aof

Conclusions