The line scanning voltammetry was used to study the electrochemical reaction of Yb(Ⅲ) in NaCl-KCl equimolar mixture on the Fe cathode. It was found that the reduction of Yb(Ⅲ) to yb(Ⅱ ) was realized on Fe electrode in the first step. Yb(Ⅱ ) was then reduced and formed alloys with Fe. The diffusion coefficients of Yb(Ⅲ) and Yb(Ⅱ ) in NaCl-KCl were de-termined to be 2.0× 10-5cm2. s- 1 and l .1 × 10-5cm2’s- 1 at 760 ℃, respectively. The diffusion activation energy of Yb(Ⅲ ) was 66.0kJ ’mol-1.
