Determination of the parameters which are affect in stability of pigments in ceramic ink formulations

The aim of the thesis is the investigation of the colloidal properties of inorganic pigments using in ceramic inks and determine the effect of the parameters on their stability. To achieve this aim, chemical stabilities of industrially available blue Co-aluminat, Co-silikat, and V-zirkon pigments in aqueous and non-aqueous suspensions were investigated. Both Co-aluminate and V-zircon pigments had insufficient chemical stability in diethylene glycol (DEG) medium with respect to aqueous suspensions. Ion concentration was found higher than that of aqueous one depend on time. Addition of polyethylene imine (PEI), Darvan C, sodium tripolyphosphate (STPP) and oxalic acid to provide passivation layer on pigment particle surface. These additives have no significant effect on chemical stability of pigment particles. Dissolution mechanism of pigment particles in aqueous and non-aqueous media was also discussed. Pigments in aqueous suspensions dissolve depending on proton promoted and ligand promoted dissolution mechanism where as ligand promoted dissolution mechanism is dominant mechanism in DEG medium.