Low temperature preparation of Cr-doped rutile pigments with good colour properties

Cr-doped rutile pigments were prepared by calcination of doped rutile precursors resulting from the hydrolysis-precipitation method. The pigment properties were investigated by X-ray diffraction, Thermogravimetry–differential scanning calorimetry, scanning electron microscopy, energy dispersive spectroscopy, diffuse reflection spectroscopy, Raman spectroscopy, and colourimetry. The pigments were found to have a rutile phase composition. Rutile pigments with good colour properties can be acquired by calcination from 500 °C to 900 °C. The pigment with 1.25% dopant and calcination at 700 °C presented optimal colour properties (L* = 75.46, a* = 15.24, b* = 39.46). The pigments presented high dispersion and could be dispersed directly into polyurethane paint and polyurethane epoxy resin without further modification.

► Rutile was used as a precursor to prepare a Cr-doped rutile pigment.
► Calcination was implemented at low temperature (500–900 °C).
►  The pigments presented good colour properties.
► The pigments showed homogeneous dispersion without any milling and sieving.
►  The pigments were photocatalytically inert.