Nonstoichiometric reactions producing ceramic pigments

Abstract

The reactions synthesizing diopside ceramic pigments using natural minerals -talc and wollastonite -have been investigated. For the initial components taken in a nonstoichiometric ratio the yield of the main reaction product -diopside -increases in two of the three reactions studied, while in the third reaction a change of the stoichiometry of the input components results in a lower content of diopside. It is found that for a small deviation from stoichiometry the dominant crystal structure of the pigment changes, which in turn fundamentally changes the color of the pigment.

Development of a β-LiAlSi2O6:Cr-based Ceramic Pigment by Proteic Sol-Gel Process Using Gelatin: Synthesis and Characterization

“…Several methods can be used for the oxide pigments synthesis, the most common being the solid-state reaction, based on the ionic diffusion process. However, the high temperatures used and problems with homogenization are disadvantages of this method 17 . Therefore, solution chemical synthesis techniques are preferably employed to reduce synthesis temperatures and produce materials with good homogeneity, such as sol-gel, Pechini 18 , combustion method, among others.…”

Síntese de pigmento cerâmico verde com base na estrutura cristalina da wollastonita

“…Estes pigmentos são obtidos a partir de matérias primas ricas em silício, cálcio, magnésio e óxi-dos fonte de íons cromóforos como Cobalto, Níquel, Cromo e Vanádio [11]. Entre as matérias primas empregadas podem ser consideradas matérias primas comerciais na forma de reagentes de elevada pureza, minérios [12] ou mesmo subprodutos agroindustriais [13] e industriais [14].…”