Synthesis of a pigment of monodispersive spherical silica particles coated with neodymium disilicate

Spherical silica (SiO2) particles coated with neodymium disilicate (Nd2Si2O7) layer were prepared by a modified Pechini sol-gel method. The phase, structure and morphology of the prepared core-shell particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM), respectively. The results reveal that the obtained particles consist of amorphous SiO2 core and crystalline Nd2Si2O7 shell, which have a perfect spherical shape with narrow size distribution, smooth surface and non-agglomeration. The SiO2@Nd2Si2O7 particles possess light-violet and light-blue colors (a*=3.46 and b*= 8.19) due to the characteristic absorption bands of neodymium element. In addition, the formation process of the core-shell SiO2@Nd2Si2O7 particles was also discussed. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.