|
Vol.41, No.10, 677 ~ 688, 2003
|
| Title |
| Effect of Corrosion Products of Hot-Dip Al-Cr Steel Sheet on the Corrosion Resistance in Salt Corrosive Environment |
| 임병문 Im Byeong Mun , 홍승현 Hong Seung Hyeon , 정재인 Jeong Jae In , 최장현 Choe Jang Hyeon , 정원섭 Jeong Won Seob |
|
|
|
| Abstract |
| The effect of corrosion products of hot-dip Al-Cr steel sheet on the corrosion resistance were investigated. The results of XRD and XPS measurements showed that there was not found a hydroxide type corrosion product on the surface of aluminized steel after salt spray test(SST) but there was found some cracks in the surface layer which accelerates corrosion during SST. In Al-Cr coated steel case, the main phase of the corrosion products after salt spray test was found to be Al(OH)₃. The polalization curves of aluminized steel after SST shows that there was no passivation layer. For the Al coated layer, a porosity in the Al-oxide film on the surface layer leads to preferential corrosion. After the Al coated layer was completely removed, the Al_(5)Fe₂layer was selectively corroded and then, the steel substrate was exposed to the electrolyte. However, the polalization curves of Al-Cr coated steel after SST shows that the passivation layer was formed, which could increase the corrosion resistance of Al-Cr coated steel. In case of the Al-Cr coated layer, the densely covered hydroxide layer of Al(OH)₃and the intermetallic compound layer of Al_(13)Cr₂became a barrier against further corrosion after the Al layer was removed. In this case, corrosion was not proceeded even through the same current density. The densely covered hydroxide of Al(OH)₃and the intermetallic compound layer of Al_(13)Cr₂were considered to be one of the reasons of high corrosion resistance for Al-Cr coating. |
|
|
| Key Words |
| Hot-Dip Al-Cr Steel Sheet, Corrosion resistance, Corrosion product |
|
|
 |
|
