Abstract
Silicide coatings on Nb/NbCr2 alloy were prepared by pack cementation method. The oxidation behavior of the bare-and coated-alloy was examined by isothermal test at 1250℃ in static air. The results show that the silicide coatings are composed of (Nb,Cr)Si2 and (Cr,Nb)Si2 phases. There exist a transitional layer of (Nb, Cr)5Si3 in between the main coating and substrate. The coating growth kinetics at 1250℃ fits to parabolic law. The oxidation of Nb/NbCr2 alloy resulted in alternate layers of Nb2O5 and CrNbO4 with porous structure, which was wrinkling even spalling off after oxidation. The scale formed on the silicide coating after oxidation at 1250℃ was mainly composed of SiO2 and CrNbO4. The scale was relatively dense and had a good bond with the residual coating, thus showing an excellent oxidation resistance.
| Original language | English |
|---|---|
| Pages (from-to) | 410-416 |
| Number of pages | 7 |
| Journal | Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research |
| Volume | 29 |
| Issue number | 6 |
| State | Published - 25 Jun 2015 |
Keywords
- Laves phase NbCr
- Materials failure and protection
- Pack cementation process
- Silicide coating, oxidation resistance