Authors: A. Fernández-Osorio, D. Hernández- Mendoza, E. Pineda-Villanueva
Affilation: Universidad Nacional Autónoma de México, Mexico
Pages: 448 - 451
Keywords: nanoparticles, spinel pigments, solid solutions, optical properties
New inorganic pink pigments based on nanocrystalline (Zn1-xCox)Al2O4 solid solution, were prepared using the hydrothermal method, obtaining nanoparticles below 8 nm. The spinel ZnAl2O4 was chosen as host hue to introduce Co(II) ions, because zinc aluminate is colorless and presents great thermal stability. The most straightforward way to obtain blue colors in bulk ceramics is by means of cobalt, Co(II) ions exhibit, when tetrahedrally coordinated, highly saturated blue shades, nevertheless these nanoparticles show a brilliant pink color due to partial substitution of Al(III) ions in octahedral sites. The samples characterization was performed by X-ray diffraction and diffuse reflectance spectroscopy. The morphology of the nanoparticles was studied by high-resolution transmission electron microscopy and their color properties were estimated by CIE L* a* b* system. The effects of Co(II) concentration and heating temperature on the spinel structure and the optical properties of the solid solution were systematically studied. These spinel nanoparticles fulfil current technological requeriments for ceramic pigments of high-temperature due to their thermal stability up 1400°C.