Oxide whisker growth on contaminated aluminum-containing stainless steel foil
US4588449A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1984 |
| Grant date | May 13, 1986 |
| Priority date | — |
| Expiry date | Dec 3, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C8/10
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
In aluminum-containing stainless steel foil, the presence of magnesium impurity in an amount greater than about 0.002 weight percent has been found to inhibit formation of a preferred oxide surface layer characterized by multitudinous oxide whiskers of a type suitable for tightly bonding an applied coating. A method for purifying magnesium-contaminated foil comprises heating the foil to selectively vaporize the magnesium while avoiding incipient melting of the base alloy, preferably between about 1000.degree. C. and 1150.degree. C. The magnesium vapors escape into a suitable ambient phase such as a vacuum or a dry hydrogen gas. Thereafter, the foil is oxidized under conditions effective to produce the desired whiskers. A preferred steel is composed of an iron-base alloy comprising about 15 to 25 weight percent chromium and 3 to 6 weight percent aluminum, and optionally may contain cerium or yttrium in an amount effective to promote oxide adherence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.