Masao Maki

The Oxidation Resistance and Corrosion Resistance of Al2O3 Cladded Foils.

Al2O3 films were formed by the oxidation heat treatment of double Al overlay cladded foils of Fe-15Cr-3Al and Ni-20Cr(NCH 1) metals to improve the oxidation resistance and corrosion resistance. In the case of oxidation heating of the aluminium cladded NCH 1 foil, Ni-Al intermetallic compounds were also formed at the interface of aluminium and NCH 1.The results of the high temperature oxidation test and corrosion test on them are underhere;(1) Weight gain of Al2O3 cladded Fe-15Cr-3Al foil is equal to that of Fe-20Cr-5Al alloy when heated at 1100°C in air. Salt water dropping test on to the foils heated at 800°C shows superior corrsion resistance property of Al2O3 cladded Fe-15Cr-3Al foil. This result seems to be due to the difference of Al2O3 growth.(2) Al2O3 cladded NCH 1 shows good oxidation resistance at 1000°C, but the weight gain increases sharply after 27h at 1100°C. On the other hand, the corrosion resistance of Al2O3 cladded NCH 1 is superior to NCH 1. This result seems to be caused by the Ni-Al intermetallic compounds formed in the interface of aluminium and NCH 1.(3) The high temperature life test of Al2O3 cladded NCH 1 shows four times longer than that of NCH 1. This result seems to be due to the improvement of the oxidation resistance by Al2O3 and the high temperature strength by the Ni-Al intermetallic compounds.