Effects of low-melting temperature salt (Na₂SO₄) addition on the phase transformation, crystal growth, and chroma of titanium dioxide pigments

Abstract

The effects of the presence of a low-melting temperature inorganic salt (sodium sulfate) on the phase transformation, particle morphology and chroma of titanium dioxide white pigment were investigated. Powders were characterized by X-ray powder diffraction, scanning electronic microscopy, ultraviolet-visible-near infrared spectroscopy, infrared spectra and chroma measurements. For titanium dioxide pigments containing a lower salt content, the anatase-rutile phase transformation and crystal growth of titanium dioxide were inhibited. On the other hand, the anatase-rutile phase transformation and crystal growth of titanium dioxide was accelerated by the addition of higher salt concentrations. T..