Alkali resistant glass compositions
US7744689B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 2006 |
| Grant date | Jun 29, 2010 |
| Priority date | — |
| Expiry date | Mar 15, 2029 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C2218/35
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An alkali resistant glass composition having improved durability to withstand highly alkali environments at elevated temperatures, such as curing of cementitious products in an autoclave, is conveniently formed from economical and abundant materials. The glass composition includes increased levels of calcium and iron, and relatively low levels of alkali metals, as compared to many other alkali resistant glass products, and comprises essentially of, by weight, >35% Si2O3, 1-25% CaO, 1-15% Fe2O3, 1-10% R2O, and an amount of Al2O3 such that the ratio of Si2O3:Al2O3 is greater than or equal to 1. Alkali resistance can be improved by forming a passivity layer on the surface of glass articles by treating the articles hydrothermally in a basic environment. Optionally zirconia and/or titania may be added to the composition to further improve alkali resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.