Formation of inorganic conductive coatings on substrates

Abstract

Precursor formulation for producing conductive coatings, e.g. nickel sulfide, on substrates such as fiberglass, comprising a soluble metal salt such as nickel acetate, a sulfur donor such as thiourea, a suitable solvent such as water or methanol, and a thickening agent to increase the viscosity of the precursor solution, such as the polyester formed by incorporating ethylene glycol and citric acid, or by addition of xanthan gum, into the precursor formulation. By employing a combination of xanthan gum and locust bean gum the precursor solution can be converted to a gel form. The conversion of the precursor composition into a thickened or gelled form facilitates its application in desired amount and without undue evaporation of solvent, onto a preselected area of the substrate, to form conductive patterns or gradients by various printing processes such as the gravure and transfer processes. Upon heating the coated substrate to a temperature which reacts the metal salt and the sulfur donor of the precursor coating to form the conductive metal sulfide, e.g. nickel sulfide, on the substrate, the polyester or gum additive is pyrolyzed and is substantially removed from the conductive coating.