Synthesis and doping of high-temperature resistant spinel nano pigments: A review

Spinel nano-pigments are high-performance super small particles, combining the stable properties of the spinel structures with the high activity of Nanomaterials. While entrapment of highly toxic yet beautiful chromophores in the spinel structure diminishes the toxicity and improves the thermal resistance, a high surface area provided by the nano-scale pigments results in a uniform bright coating with a sufficiently high color strength and enhanced light transmission. Although the spinel nano pigments are promising for the coating and ceramic industries, the applications are limited, mostly due to the required high sintering temperature. Various synthesis processes have been tried for these pigments with the sol-gel method being the most frequent one. Many elements have been considered as dopants for these spinel systems to enhance, change, or improve the optical and physical properties. This comprehensive review aims to summarize the work done in this field, covering almost 20 years of research dedicated to the synthesis and doping of spinel nano pigments.