Research Output
Dielectric properties and microwave absorbing properties of silicon carbide nanoparticles and silicon carbide nanowhiskers
Microwave synthesis of silicon carbide nanowhiskers: Effect of molar ratio
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Publication
Silicon carbide (SiC) is well known for their outstanding microwave absorbing properties. SiC nanomaterials (SiCNMs) are expected to have better microwave absorption performance due to their high specific surface area. To date, no study was reported to compare the dielectric properties and microwave absorbing properties of different type of SiCNMs. Therefore, the objective of this paper is to compare the dielectric properties and microwave absorption properties of different types of SiCNMs. In this paper, SiC nanoparticles (SiCNPs) and SiC nanowhiskers (SiCNWs) were characterised using SEM and XRD. In addition, their dielectric properties and microwave absorbing properties were measured using network analyser and transmission line theory. It was found that SiCNWs achieved higher dielectric constant and loss factor which are and εr’ =17.94 and εr″ = 2.64 compared to SiCNPs that only achieved εr’ = 2.83 and εr″ = 0.71. For microwave absorbing properties, SiCNWs and SiCNPs attained minimum reflection loss of -10.41 dB and -6.83 dB at 5.68 GHz and 17.68 GHz, respectively. The minimum reflection loss of SiCNPs and SiCNWs obtained in this study is much lower than the nanometer-SiC reported previously. These results suggested that SiCNWs can be an ideal candidate of microwave susceptors for various microwave applications
Publication
Silicon carbide (SiC) is an attractive material for its excellent properties such as wide band gap, high chemical stability and thermal conductivity. The conventional methods for the preparation of SiC are time and energy consuming. In this paper, SiC nanowhiskers were synthesized by utilizing microwave heating. Mixture of graphite and silica of various ratio was heated to 1400 °C for 30 min at a heating rate of 20 °C/min. It was found that almost complete conversion of graphite and silica to silicon carbide nanowhiskers was observed for sample of mixture in the ratio of 1:3. Vapor-solid mechanism was suggested to explain the formation of SiC nanowhiskers.