Synthesis of Si-Based Refractory Compounds from Coconut Shell by Carbothermal Method

Abstract

The synthesis of Si-based refractory compounds from coconut shells (CS) by carbothermal treatment was investigated. Coconut shells, an agro-waste was utilised in the processing of the Si-based refractory compounds in a single stage carbothermal processing route. The treatment scheduled was carried out in a conventional heat treatment furnace at a temperature window of (900-1900 °C) at 10 °C/min heating rate in a controlled atmosphere. X-ray Diffractometer (XRD) was used to analyzed and quantify the crystalline and amorphous phases in the reaction products. The results from Fourier transform infrared spectroscopy (FTIR) revealed that, the dominant functional groups present after the carbothermal treatment were mainly Si-O-Si and Si-C groups. Also, the XRD results showed that the polytypes are mainly of α-SiC type precipitating as hexagonal symmetry of 6H-SiC and 4H-SiC type. The silica polytypes amount to about 8-14 wt.% of the silica polytypes as observed for different processing temperatures adopted. However, the total yield of SiC-made up between 11 to 40 wt.% of the crystalline phases as identified by XRD from the process. It is evident that the adoption of this processing route is a viable option for the synthesis of coconut shells as potential reinforcement for composites design.