The mechanism of NaCl-induced hot corrosion and the effect of alloying elements were investigated in Nb-bearing ferritic stainless steels. The main results obtained were as follows: (1) Na4 promotes chloride-induced corrosion at elevated temperatures, because Cr2O3 formed at elevated temperature reacts with Na* and becomes Na2CrO4, which is soluble to water. This reaction exposes the chromium-depleted zone to the surface and hence accelerates the oxidation. (2) This type of corrosion resistance is improved by the addition of Mo. Mo precipitates at grain boundaries as Lavesphase as well as Nb. Precipitation of Laves phase, which suppresses the grain boundary diffusion of oxygen and likely improves NaCl-induced hot corrosion resistance.
|Number of pages
|Review of Automotive Engineering
|Published - Jul 1 2007
All Science Journal Classification (ASJC) codes
- Automotive Engineering