Transparent polycrystalline aluminium oxide

US7396792B2 · kind B2 · utility

Assignees

• KONINKLIJKE PHILIPS ELECTRONICS NV · NL
• Max-Planck-Gesellschaft zur Föderung der Wissenschaften e.V. · US

Inventors

• Michel Paul Barbara Van Bruggen · Helmond, NL
• Rolf Theo Anton Apetz · Aachen, DE
• Theo Arnold Kop · Haarlem, NL
• Andreas Krell
• Thomas Hutzler · Dresden, DE

Key dates

• Filing date: Jul 2, 2003
• Grant date: Jul 8, 2008
• Expiry date: Aug 6, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B35/6455
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The present invention relates to highly dense translucent and transparent aluminium oxide components for applications, e.g. in the lighting industry, where a fine crystal size has to be obtained and stabilized for use at temperatures of 800° C. or more. Disclosed are high-strength polycrystalline alumina products which include 0.001-0.5 weight-% ZrO2 stabilizing a fine crystal size <2 μm or, preferably, <1 μm if used at temperatures of 800° C. or more. The microstructure exhibits an extremely high relative density enabling a high real in-line transmission >30% measured over an angular aperture of at most 0.5° at a sample thickness of 0.8 mm and with a monochromatic wavelength of light λ, preferably, of 645 nm.