1991 Volume 77 Issue 8 Pages 1274-1279
In order to understand the effects of the various alloying elements on the equilibrium constant of deoxidation of liquid nickel, the deoxidation of nickel based alloys with silicon has been studied at temperature range between 1550°C and 1650°C by the use of silica crucible.
In nickel-chrominium alloy, the deoxidation product, logK'Si(Ni-Cr), which drastically increased by the addition of chromium up to 20 pct chromium, was empirically represented to be.
logK'Si(Ni-Cr)=log K'Si(Ni) + 0.347[%Cr]-0.010[%Cd]2
Cr<15%, 0.65 % Si, 1550°C1650°C
while the deoxidation product in nickel-molybdenum alloy, logK'Si(Ni-Mo), which also lineally increased with increasing molybdenum content, was given by the expression :
log K'Si(Ni-Mo) = log KSi(Ni)+0.047[%Mo]
Mo<16%, 0.65% Si, 1550°C1650°C
In nickel-tungsten alloy, the value of log K'Si(Ni-W) was found to be as follows :
log K'Si(Ni-W) = log KSi(Ni)+ 0.007[%W]
Mo<11%, 0.4% Si, 1550°C1650°C
For the effect of the alloying elements on the activity coefficient of oxygen in nickel, the following parameters were obtained :
logfCrO(Ni) = -0.171 [%Cr] Cr<5%
log fMoO(Ni)=-0.025[%Cr] Mo<16%
logfWO(Ni)=-0.004[ %Cr] W<11%
