Synthesis of Hexagonal Boron Nitride Coatings Using Concentrated Solutions of Alkali Metal Borates

Abstract

Continuous nanocrystalline coatings of hexagonal boron nitride (h-BN) with a thickness of ~1000‒350 nm are prepared from highly concentrated aqueous solutions of lithium and sodium borates, which display good film-forming properties. The borate solutions were applied on silicon substrates by spin coating followed by drying in air and treatment in ammonia at a temperature of 1300°C. This method is deemed promising for creating protective coatings (e.g., for protecting carbon products from oxidation at elevated temperatures).