Stainless steel for ozone added water and manufacturing method thereof
US5944917A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 29, 1997 |
| Grant date | Aug 31, 1999 |
| Priority date | — |
| Expiry date | May 29, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D6/002
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A stainless steel having excellent corrosion resistance to ozone added water, such as ozone added ultrapure water used in semiconductor manufacturing processes and the like, as well as a manufacturing method. The stainless steel comprises a base metal and an oxide film formed on the surface of the base metal, the base metal being a stainless steel which contains 12 to 30% of Cr, 0 to 35% of Ni, and 1 to 6% of Al and Si while the contents of the other alloying elements are limited to as low a level as possible, the oxide film mainly comprising Al oxide or a Si oxide or both. The oxide film may be formed on the base metal surface through the dry oxidation process or the wet oxidation process. In the stainless steel, metallic ions are rarely dissolved from the base metal into the ozone added water. Also, since the contents of alloying elements, other than Cr, Ni, Al, Si, and like necessary elements, are limited to a low level, the stainless steel exhibits excellent corrosion resistance and reduced particle emission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.