Effects of Alloying Elements on High Temperature Oxidation of 42% Ni Iron-based Alloy
Tadashi INOUE, Akio KOBAYASHI, Katsuhisa YAMAUCHI, Yoshihiro HOSOYA
The effects of alloying elements on the high temperature oxidation of laboratory melted 42% Ni iron-based alloy were investigated. A mechanism controlling the high temperature oxidation of 42% Ni alloy has been also discussed.
In the temperature range between 1000°C and 1200°C, scale, intraglanular oxidation layer and intergranular oxidation layer progressed. Addition of Cr was effective on reducing the oxide layers while addition of C and Mn didn't reduce the oxide layers markedly.
It was suggested by energy dispersive X-ray spectroscopy that oxidation layers were formed mainly by the selective-oxidation of Fe in 42% Ni alloy. The mechanism of reducing the oxide layers of 42% Ni alloy by the addition of Cr was thought to be attributed to the formation of Cr-oxide and Ni-oxide in which diffusion coefficients of metallic ion are very low value.
Marker test also revealed that the scale forming was controlled by the outer diffusion of metallic ion through the scale.