Polymerizable precursor method vs solid state reaction for the synthesis of Ni3(PO4)2 yellow hue pigment with advanced characteristics

In view of the rapid development of printing and electrophoretic display technologies, there is a high demand for pigments with pre-defined physical properties and pure colouration of one of the three subtractive CMY primaries (cyan, magenta or yellow). This contribution focuses on the development of an appropriate synthesis method of the yellow-hue Ni3(PO4)2 inorganic phosphate with the purpose to enable its application in advanced light reflective technologies. Polymerizable precursor method (PPM) and solid state reaction (SSR) were utilized for the synthesis and the results were evaluated with regards to phase composition, crystallinity, particle morphology and size distribution, surface area, porosity, density, optical reflectance and colour parameters of the product. Accordingly, PPM provides a number of advantages in comparison to SSR and to literature data reporting other inorganic yellow-shade pigments. Ni3(PO4)2 obtained by PPM fulfils two main demands as a subtractive primary pigment: ideal yellow shade and uniform spherical micron-sized particles morphology. Moreover, the product shows darker and saturated colouration, especially when taking into account the low particle size distribution which typically reduces colour saturation and increases lightness of the product. The obtained pigment with bright yellow colouration, that represents one of the CMY primaries, has a high potential for application in printing technologies and, after appropriate modification, in electrophoretic displays.