Methods for reducing zirconia defects in glass sheets
AssigneeCorning Incorporated
InventorsAdam James Ellison, Timothy James Kiczenski, John Christopher Mauro
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Abstract
Methods are disclosed for treating zircon-containing forming structures, e.g., zircon isopipes, with one or more treatment glass compositions in which defect-causing reactions between the zircon of the forming structure and molten glass are suppressed at the delivery temperature of the treatment glass. The treatment compositions can be used during start-up of a forming structure, between runs of the same production glass on a given forming structure, and/or when transitioning between runs of two production glasses on a given forming structure. The treatment compositions can be used with production glasses that are ion-exchangeable.
Claims17
A treatment process for treating a forming structure in preparation for producing glass sheets from molten glass having a production composition, said forming structure having an outer surface at least a part of which is composed of zircon and comes into contact with the molten glass during use of the forming structure, said treatment process comprising:
- (A) melting batch materials to produce molten glass having a treatment composition, said batch materials comprising silica;
- and
- (B) delivering the molten glass having the treatment composition to the forming structure at a delivery temperature Tdelivery/treatment;
- wherein:
- at Tdelivery/treatment, the treatment composition promotes the reaction:
- ZrO2+SiO2→ZrSiO4;
- and
- (ii) the treatment process reduces the level of zirconia defects in glass sheets produced from the production composition using the forming structure.
Dependencies are inferred from the claim text.