Transparent glass-ceramic of light brown color and method of making
US4526872A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 22, 1984 |
| Grant date | Jul 2, 1985 |
| Priority date | — |
| Expiry date | Feb 22, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C10/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention is primarily concerned with the production of transparent glass-ceramic articles especially suitable for use as cooking utensils nucleated with up to 6% TiO.sub.2 and containing up to 0.25% Fe.sub.2 O.sub.3 and, perhaps, up to 0.1% MnO.sub.2, which exhibits a light brown tint that the human eye perceives essentially constant when the dominant wavelength is held between 577-581 nm, purity between 8-15%, and the transmission factor between about 65-80. The desired tint is obtained by including 0.0025-0.02% CoO+Cr.sub.2 O.sub.3, consisting of 0.001-0.01% CoO and 0.001-0.01% Cr.sub.2 O.sub.3, in the base composition of the glass-ceramic. An opaque glass-ceramic article exhibiting a light, warm creamy color perceived by the human eye as essentially constant when the dominant wavelength is held between 570-585 nm, the reflectance factor is in excess of 64, and the purity factor is no greater than 8% can be produced from like base compositions which are crystallized in situ at higher temperatures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.