Effects Of Surface Treatments On Crack Initiation In Glasses

The strength of glass is controlled primarily by surface discontinuities (cracks) which are introduced into the surface during processing or during services. Most of these surface cracks are caused by contact between the glass and hard objects, including other pieces of glass. Microindentation testing is a way to study crack initiation due to contact loading under controlled conditions. In this study three glasses were used; (i) a soda-lime-silica (float glass from AFG Ind Inc, 5mm thick); a vitreous silica (7940 from Corning 3.5mm thick); and a borosilicate (7740 from Corning 4mm thick).