Simple approach to fabricate SiC–SiO2 composite nanowires and their oxidation resistance
✍ Scribed by Wasana Khongwong; Katsumi Yoshida; Toyohiko Yano
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 631 KB
- Volume
- 173
- Category
- Article
- ISSN
- 0921-5107
No coin nor oath required. For personal study only.
✦ Synopsis
A simple thermal evaporation technique without catalysts from an exterior has been developed to synthesize SiC-SiO 2 composite nanowires. Silicon powder of micrometer size or coarser silicon powder was heated in a horizontal tube furnace up to 1350 • C under CH 4 gas flow. Large quantity of as-grown wool-like products was obtained on the silicon powder oxidized at 800 • C in air for 1 h. Characterization by an X-ray diffractometer, a field-emission scanning electron microscope, a transmission electron microscope and an infrared spectroscope indicated that these products were SiC core/SiO 2 shell composite nanowires. SiC core diameter was approximately 20-80 nm with SiO 2 shell of about 10-20 nm in thickness and length up to 1-2 mm. Both of separate heating process, i.e., heating for oxidation of raw Si powder and nanowires synthesis reaction separately, and continuous heating process, i.e., multi-step continuous heating for oxidation and reaction, could produce SiC-SiO 2 core/shell nanowires. Based on thermogravimetric analysis, it was suggested that the synthesized nanowires had better oxidation resistance than that of SiC nano-sized powder.