The Effect of Chromium on the Activity of Nitrogen in Fe-28% Ni Austenite at 1000°C

Abstract

A capsule technique was employed to investigate the effect of chromium on the activity of nitrogen in Fe-28%Ni-Cr-N austenite at 1000°C in a high chromium concentration range between 15 and 30%. The activity of nitrogen in the system is adequately described by the following equation:
log a_N=log (%N)+e^Cr_N(%Cr)+e^Ni_N(%Ni)+r^Cr_N(%Cr)²+r^{Cr, Ni}(%Cr)(%Ni), where numerical values for e^Cr_N and e^Ni_N are evaluated from the data in Fe-Cr-N and Fe-Ni-N systems, respectively.
The values of the secnd order interaction parameters, r^Cr_N and r^{Cr, Ni}, determined in the present investigation, are 0.0021₃ and -0.0003₃, respectively, at 1000°C.