The influence of additives,OP-21,polyethylene-glycol400 (PEG400) and/or benzalacetone(BA),on the electrodeposition process of zinc in chloride acidic baths was studied by linear sweep voltammetry (LSV),cyclic voltammetry (CV) and chronoamperometry.The results show that the ternary mixture of OP-21,PEG400 and BA,can more markedly increase the overpotentials of zinc deposition and hydrogen evolution than a single additive or binary mixture.Based on the results obtained from fitting current transients by the Scharifker-Hills nucleation model,it is found the zinc deposition mechanism depends to some extent on the additives used.In solutions containing PEG400 and/or BA,the zinc deposition experiences the same nucleation as that in the additive-free solution,which follows the instantaneous nucleation model.In the solution containing OP-21,the zinc deposition mechanism follows progressive nucleation model at the beginning and then follows the instantaneous nucleation model.In the solution containing PEG400,BA and OP-21,the zinc deposition mechanism follows the progressive nucleation model.The results obtained from SEM observation show that the deposited zinc in the solution containing the ternary mixture has finer grain size than that in the solution containing the binary mixture.