Strengthening and toughening of soda-lime glass by a reinforced coating

The strength and toughness of soda-lime (container) glass have been enhanced by factors of ∼ 2 and ∼ 40, respectively, by a 0.1 mm coating of polyurethane containing 6–9 wt% silicon carbide whiskers in random orientation. The strength measurements were made using a standardized procedure and a biaxial ring-on-ring flexure rig. The toughness enhancement has been shown to be due to crack-branching and fibre pull-out mechanisms in the coating, which bridges any strength-limiting flaws in the underlying glass.