Abstract: Cyclic voltammetry was used to study the electroreduction of Ho(III) i n Ho(NO3)3LiClO4DMF. The results showed that traces of water in this system blocked the electroreduct ion of Ho(III) by forming LiOH and Ho(OH)3 films on the electrode surface. Cod eposition of Ho and Ni was studied in dimethylformamide by cyclic voltammetry an d potentiostatic deposition at room temperature. Potentiostatic deposition was u sed to prepare HoNi alloys. EDAX, SEM and XRD were used to analyze the films. The results indicated that black, adhesive and amorphous HoNi alloy films on C u were produced where the content of Ho could be as high as 72.7 ％.

Key words: Rare earths, Potentiostatic deposition, Dimethylformamide, Ho-Ni alloy