The effect of silica-to-magnesium ratio on magnesium silicide coated carbon nanotubes

In this work, the synthesis of magnesium silicide carbon nanotubes is reported by assessing the effect of two different silica-to-magnesium ratios. Commercial carbon nanotubes were coated with silica via the sol–gel process, whereas a magnesiothermic reaction was employed by employing different magnesium percentages by weight, relevant to the coated silica. The final structures were assessed quantitatively and qualitatively using thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In addition, the resulting nanostructures were used as fillers to manufacture epoxy composites, and their potential thermoelectric properties were assessed via I–V measurements in various temperature differences. The composites manufactured with a silica-to-magnesium ratio of 3:1 exhibited a sevenfold increase in current intensity compared to the sample with a 1:1 ratio, whereas decreasing the composite’s epoxy content produced a tenfold increase in current intensity with increasing temperature differences of up to 106 °C. This work further improves the synthetic parameters for the synthesis of magnesium silicide carbon nanotubes, concerning the silica-to-magnesium ratio, whereas an approximation of their potential thermoelectric properties is being presented utilizing I–V measurements.