Optical characteristics of nano-forsterite powders with natural silica sand as source of Si

Nano forsterite powders have been successfully synthesized via ultrasonic assistant for the starting materials and followed by solid reaction and calcination steps. The synthesis products were greenish powders with forsterite as the dominating phase as revealed by XRD data analysis. The formation of forsterite was also confirmed by FTIR spectrometry and supported by SEM images. The phase composition after calcination at 950 °C for 4 h was 93.9 wt% forsterite and 6.1 wt% periclase. The forsterite crystal was nanometric according to the XRD data, while the density of the powder was 2.88 g/cm³. UV-Vis spectrum of the powder showed relatively strong absorption peaks particularly at 635, 660, 670, 680, 695 and 705 nm which can be associated with the greenish color of the product and is different from previous studies. Therefore, it can be concluded that high purity greenish forsterite can be formed at 950 °C calcination temperature as previously reported, except that the raw materials were subjected to ultrasonic treatment.