Sains Malaysiana 46(7)(2017): 1069–1074 http://dx.doi.org/10.17576/jsm-2017-4607-08 Effect of Heating Duration on the Synthesis of Silicon Carbide Nanotubes by Microwave Heating of MWCNTs and Silica (Kesan Tempoh Pemanasan terhadap Sintesis Tiub Nano Silikon Karbida oleh Pemanasan Gelombang Mikro MWCNTs dan Silika) TONY VOO CHUNG SUNG, VOON CHUN HONG*, LEE CHANG CHUAN, SUBASH C.B. GOPINATH, LIM BEE YING, MOHD KHAIRUDDIN MOHD ARSHAD, FOO KAI LOONG, UDA HASHIM, RUSLINDA A. RAHIM, MOHD NASHA AIN BIN NORDIN & NOR AZIZAH PARMIN ABSTRACT In this article, the effect of heating duration on the synthesis of silicon carbide nanotubes (SiCNTs) was reported. SiCNTs were synthesized from blend of silicon dioxide (SiO 2 ) and multi-walled carbon nanotubes (MWCNTs) in the ratio of 1:3 by using the microwave heating at 1400°C and maintained at duration of 20, 40 and 60 min, respectively. SiCNTs synthesized at heating duration of 40 and 60 min showed the presence of single phase β-SiC in X-ray diffraction patterns. Meanwhile, feld emission scanning electron microscope images showed that SiCNTs were formed and no residual of SiO 2 and MWCNTs was observed for SiCNTs formed at heating duration of 40 and 60 min. Transmission electron microscopy images showed the SiCNTs have inter-planar spacing of 0.263 nm and tubular structure of nanotube were retained. The peak corresponded to β-SiC was observed at wavelength of 465 nm from the photoluminescence spectroscopy and associated with energy band gap of 2.67 eV. Absorption bands of Si-C bond were detected at 806.23 cm -1 from the Fourier transform infrared spectra. High purity SiCNTs was obtained at 40 and 60 min as indicated by low weight loss by thermo-gravimetric analysis. 40 min is the most suitable heating duration for the synthesis of single phase β-SiCNTs. Keywords: Microwave processing; multi-walled carbon nanotube; silicon carbide nanotube; silicon dioxide; sintering ABSTRAK Dalam kertas ini, kesan jangka masa pemanasan terhadap sintesis tiub nano silikon karbida (SiCNTs) telah dilaporkan. SiCNTs telah disintesis daripada campuran silikon dioksida (SiO 2 ) dan tiub nano karbon berbilang dinding (MWCNTs) dalam nisbah 1:3 dengan menggunakan pemanasan gelombang mikro pada 1400°C dan dikekalkan pada jangka masa 20, 40 dan 60 min. SiCNTs yang disintesis dengan tempoh pemanasan 40 dan 60 min telah menunjukkan kehadiran β-SiC fasa tunggal dalam pola pembelauan sinar-X. Sementara itu, imej pancaran medan mikroskopi elektron pengimbasan menunjukkan bahawa SiCNTs telah terbentuk dan tiada sisa SiO 2 dan MWCNTs diperhatikan untuk SiCNTs terbentuk dengan tempoh pemanasan 40 dan 60 min. Imej mikroskopi elektron pancaran menunjukkan jarak antara satah untuk SiCNTs adalah 0.263 nm dan struktur tiub nano dikekalkan. Puncak ß-SiC diperhatikan pada jarak gelombang 465 nm dari spektroskopi fotoluminesen dan dikaitkan dengan jurang jalur tenaga sebanyak 2.67 eV. Belang penyerapan ikatan Si-C telah dikesan pada 806.23 cm -1 dari spektroskopi transformasi Fourier inframerah. Ketulenan SiCNTs yang tinggi telah diperoleh dengan tempoh pemanasan 40 dan 60 min seperti yang ditunjukkan oleh kesusutan berat yang rendah dengan analisis thermogravimetrik. 40 min adalah tempoh pemanasan yang paling sesuai untuk sintesis β-SiCNTs fasa tunggal. Kata kunci: Pensinteran; proses gelombang mikro; silikon dioksida; tiub nano karbon berbilang dinding; tiub nano silikon karbida INTRODUCTION Silicon carbide (SiC) especially silicon carbide nanotubes (SiCNTs) is known to possess outstanding properties such as high mechanical strength, high stability at high temperature and high thermal conductivity which rendered SiC a suitable material for fabrication of electronic devices for high temperature, high power and high frequency applications (Wu et al. 2015). SiCNT is structurally similar to carbon nanotubes (CNTs), but SiCNT is predicted to be more superior to CNTs for the inability of CNTs to survive in high-temperature and harsh-environment applications. SiCNT is commonly synthesized by using chemical vapor deposition (CVD) (Xie et al. 2007) and carbothermal reduction of silica by using conventional heating method (Yang et al. 2004). However, these methods possess some drawbacks. Only small quantities of SiCNTs were synthesized by using the CVD method and this method involved the use of expensive precursors. Meanwhile, carbothermal reduction of silica by carbon using the conventional heating showed some of the disadvantages such as slow heating rate, long heating duration at high temperature and non-uniform heating of raw materials