Abstract: The effect of 2-butyne-1, 4-diol (BD) concentration in sulphate plating bath on the structure of the Co-Ni deposit was studied by scanning electron microscope and X-ray diffraction, respectively. As a result, BD could smooth the deposit surface and make the diameter of grain decrease, but too much of BD was no good for the size of grain. In general, hcp phase of the Co-Ni alloy with preferentially oriented (110) plane was prepared by electro-deposition at the present of BD. The Co-Ni alloy as a catalyst for the electro-oxidation of ethanol in alkaline medium was studied by cyclic voltammetry. The deposit plated from the bath containing BD possessed better electro-oxidation of ethanol performance compared with that of the deposit plated from sulphate plating bath, but too much of BD was not benefit for catalyst activity. The Co-Ni film fitted to using as magnetic recording material.

Key words: Co-Ni, 2-butyne-1, 4-diol (BD), electro-deposition, electro-oxidation ethanol, magnetic property