| Title |
Characterization of Microstructure, Hardness and Oxidation Behavior of Carbon Steels Hot Dipped in Al and Al-1 at% Si Molten Baths |
| Authors |
(Trinh Van Trung); (Sun Kyu Kim); (Min Jung Kim); (Seul Ki Kim); (Sung Jun Bong); (Dong Bok Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2012.50.8.575 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Metals; surface modification; microstructure; scanning electron microscopy (SEM); hot-dip aluminizing |
| Abstract |
Medium carbon steel was aluminized by hot dipping into molten Al or Al-1 at% Si baths. After hot-dipping in these baths, a thin Al-rich topcoat and a thick alloy layer rich in Al5Fe2 formed on the surface. A small amount of FeAl and Al3Fe was incorporated in the alloy layer. Silicon from the Al-1 at% Si bath was uniformly distributed throughout the entire coating. The hot dipping increased the microhardness of the steel by about 8 times. Heating at 700-1000, however, decreased the microhardness through interdiffusion between the coating and the substrate. The oxidation at 700-1000 in air formed a thin protective a-Al2O3 layer, which provided good oxidation resistance. Silicon was oxidized to amorphous silica, exhibiting a glassy oxide surface. |