Codeposition of chromium and silicon diffusion coatings in FE-base alloys using pack cementation
US5364659A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1993 |
| Grant date | Nov 15, 1994 |
| Priority date | — |
| Expiry date | Sep 3, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C12/02
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Diffusion coatings incorporating approximately 18 to 35 wt % Cr and 1 to 3% Si in 2.25Cr-1.0Mo steel and 1018 steel have been produced using a pack cementation method. The codeposition of these concentrations of Cr and Si into the 2.25Cr-1.0Mo and 1018 steel requires the use of a "mixed activator" (fused salt solution of NaF and NaCl). Cyclic oxidation tests in air at 700.degree. C. of a coated 2.25Cr-1.0Mo steel coupon with a surface concentration of 34Cr-3Si have shown excellent cyclic oxidation resistance. Furthermore, a 1018 coupon coated to a surface concentration of Fe-30 wt % Cr-3Si shows negligible aqueous corrosion in an aerated 3.5% NaCl solution at room temperature. These coatings have provided similar protection in more complex oxidizing and reducing atmospheres.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.