GLASS ELEMENT WITH HIGH SCRATCH TOLERANCE

• Main Authors: HOCHREIN OLIVER, BURGER INGE, ALT KATHARINA, KISSL GORDON, WESTENBERGER IRMGARD, RUDAS GERD, PAULUS GUNTHER, ALKEMPER JOCHEN
• Format: Patent
• Language: English
• Published: 16.10.2014
• Subjects: CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; METALLURGY; MINERAL OR SLAG WOOL; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS

A glass element is provided that is made of a glass having SiO2, Al2O3, B2O3, and Na2O. The glass has a scratch tolerance that when scratches of 1 mm length are introduced using a Knoop diamond indenter which presses upon a surface of the glass with a force of 4 Newton and is displaced along the surface with a traverse speed of 0.4 mm/s, not more than 20% of the scratches have a noticeable width including visible chipping of more than 25 μm. In some embodiments, the glass, after chemical tempering, has sodium ions that are at least partially exchanged for potassium ions so that a compressive stress zone is provided at the surface of the glass. The compressive stress is at least 700 MPa and an exchange depth of alkali ions is at least 25 μm.