The diffusivities of oxygen in liquid copper and nickel were determined fro
m 1300 degreesC to 1560 degreesC by a capillary gas-reservoir method. A dif
fusion cell designed to behave as if of semi-infinite length and consisting
of liquid copper or nickel held in an alumina capillary was used. A H2O-H-
2 gas mixture maintained a constant oxygen potential at the metal-gas inter
face. A controlled furnace hot zone of 15 cm was obtained with six separate
windings of Pt-10%Rh wire. To prevent convection the top of the diffusion
cell was adjusted to be hotter than the bottom. The solidified diffusion co
lumns were sectioned and analysed for oxygen by vacuum fusion analysis. Oxy
gen diffusivities, D, were calculated through use of a solution of Fick's s
econd law. For copper D is 1.52 x 10(-8) m(2)/s at 1295 degreesC and 3.78 x
10(-8) m(2)/s at 1560 degreesC; for nickel D is 3.12 x 10(-8) m(2)/s at 14
50 degreesC and 3.39 x 10(-8) m(2)/s at 1580 degreesC. The results for copp
er can be represented by the Arrhenius relationship In D equals -19570/RT 3.21 where E and R are in calories or -81900/RT + 3.21 where E and R are i
n joules (1350-1560 degreesC) and where the numerator, E, is oxygen diffusi
on activation energy/mol K and R is the gas constant.