The deoxidation of liquid nickel-copper and nickel-cobalt binary alloys with silicon has been studied at the temperatures ranging from 1 450°C to 1 650°C using silica crucible.
On the nickel basis in nickel-copper binary, the deoxidation product, logK'_Si(Ni-Cu), which increased with the addition of copper, was expressed to be :
logK'_Si(Ni)=logK'_Si(Ni-Cu)+0.0342[%Cu]-0.0004[%Cu]² Cu<40%, 0.5%Si, 1 550°C1 650°C.
The effect of temperature on the equilibrium constants of the deoxidation reaction in copper, obtained by extrapolation, was estimated as follows :
logK_Si(Cu)=-15 680/T+2.16 1 450°C1 550°C
while the value of logK'_Si(Ni-Cu) on the copper basis was given by the expression :
logK'_Si(Ni-Cu)=logK'_Si(Cu)+0.012[%Ni]-0.0001[%Ni]² Ni<40%, 0.5%Si, 1 450°C1 550°C
On the nickel basis in nickel-cobalt binary, logK'_Si(Ni-Co) was represented to be as follows:
logK'_Si(Ni-Co)=logK'_Si(Ni)+0.005[%Co] Co<20%, 0.55%Si, 1 550°C1 650°C
The temperature dependence of the equilibrium constants for the deoxidation of cobalt was expressed to be:
logK'_Si(Co)=-15 270/T+1.81 1 550°C1 650°C
whereas logK'_Si(Ni-Co) on the cobalt basis was found to be :
logK'_Si(Ni-Co)=logK'_Si(Co)-0.001[%Ni] Ni<60%, 0.55%Si, 1 550°C1 650°C
Using the values of deoxidation product, the interaction parameters of various alloying elements were calculated.