In order to investigate the equilibrium between yttrium and oxygen in liquid iron and nickel, the deoxidation equilibrium of yttrium in liquid iron and nickel saturated with yttria has been measured at the temperature ranges from 1600 to 1700°C using the sampling technique.
The equilibrium constant for the deoxidation reaction:
Y₂O₃(s)=2Y+3O
in liquid iron was found to be:
logK_Y(Fe)(K_Y(Fe)=a_Y²a_O³/a_Y2O3)=–36160/T+7.33    1600–1700°C
while the deoxidation product, K^'_Y(Fe)(=[%Y]²[%O]³) was expressed as follows:
logK'_Y(Fe)=logK_Y(Fe)–(–17350/T+3.14)(3[%Y]+11.1[%O])    0.02<[%Y]<0.11
by the use of the interaction parameter, e_O(Fe)^Y=–17350/T+3.14.
The equilibrium constant for the deoxidation of liquid nickel, log K_Y(Ni), was determined as the expression:
logK_Y(Ni)=–36250/T+6.36    1600–1700°C
Besides, the deoxidation product of nickel was represented to be:
logK'_Y(Ni)=logK_Y(Ni)+6.47(3[%Y]+11.1[%O])    0.01<[%Y]<0.11
with the interaction parameter, e_O(Ni)^Y=–6.47 at the temperature between 1600 and 1700°C.