Corning Incorporated
Glass-based articles with improved stress profiles

Abstract:

Glass-based articles comprise: a glass-based substrate having opposing first and second surfaces defining a substrate thickness (t); a stress profile comprising: a compressive stress region extending from the first surface to a depth of compression (DOC), the DOC located at 0.04.cndot.t or deeper; and a central tension region. An alkali metal oxide is present in the central tension region. A first metal oxide whose metal has the same or smaller atomic radius as the metal of the alkali metal oxide, and a second metal oxide whose metal has a larger atomic radius than the metal of the alkali metal oxide are both present in independent concentrations that vary within at least a portion of the compressive stress region. The glass-based substrates are exposed to a multi-step ion exchange process including a first treatment of doping with ions smaller than the alkali metal oxide of the pre-fabricated glass-based substrate; and a second treatment of strengthening with larger ions to enable superior stress profile attributes. The first treatment may occur at temperatures within 300.degree. C. of the strain point of the glass-based substrate.