Chemically Strengthened Low Crystallinity Black Glass‐Ceramics with High Liquidus Viscosities. (26th May 2014)

• Record Type: Journal Article
• Authors: Dejneka, Matthew; Dutta, Indrajit; Smith, Charlene
• Is Part Of: International journal of applied glass science. Volume 5:Number 2(2014:Jun.)
• Page Start: 146
• Page End: 160
• Publication Date: 2014-05-26
• Subjects: Glass -- Periodicals; Glass manufacture -- Periodicals; 666.1
• DOI: 10.1111/ijag.12076
• Languages: English
• ISSNs: 2041-1286

Abstract

<abstract abstract-type="main" id="ijag12076-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Strong, black materials are needed for electronic device backs and appliance facings. While glass‐ceramics have good strength and toughness, their liquidus viscosity is too low to enable economical forming of these devices by the fusion or slot draw methods. Thus, we invented a new class of low crystallinity glass‐ceramics with 10–20 nm crystallites in the Fe<sub>2</sub>O<sub>3</sub>‐TiO<sub>2</sub>‐MgO system. These materials were formed into transparent glasses and then heat treated to make black opaque glass‐ceramics containing magnetite, pseudobrookite, and/or ε‐Fe<sub>2</sub>O<sub>3</sub>. The ε‐Fe<sub>2</sub>O<sub>3</sub> phase exhibited extensive solid solution (ss) between Fe<sub>2</sub>O<sub>3</sub> and MgTiO<sub>3</sub>. The blackness and opacity of the ε‐Fe<sub>2</sub>O<sub>3</sub> glass‐ceramics peaked at a ceram temperature of 750°C where the Fe<sup>2+</sup> in the crystallites was maximized, resulting in peak Fe<sup>2+</sup>‐Ti<sup>4+</sup> charge transfer absorption. The liquidus viscosity was increased to more than 100 kPa*s by optimizing the base glass composition and minimizing the amount of crystallinity, thereby enabling fusion formability. These fusion formable glass‐ceramics had strengths exceeding the best commercially available glasses after ion exchange. This work provides a new class of low crystallinity fusion formable glass‐ceramics with high strength.</p> </abstract>