Different Electrodeposition Behaviors of Ni-Co Binary Coatings in Sulphate and Chloride Baths

Ni-Co binary coatings with different compositions were electrodeposited from sulphate and chloride baths at room temperature without stirring, respectively. The different codeposition behaviors of the coatings deposited from sulphate and chloride with the same mole ratio of Ni2+/Co2+were studied and anomalous codeposition was investigated in both the sulphate and chloride baths. The Co atom content in the coatings deposited from chloride bath and sulphate bath increases with the mole ratio of Co2+/Ni2+in the baths increasing. The degree of anomalous codeposition in the sulphate bath is higher than that in chloride bath and the possible explanation was discussed. The difference of magnetic properties was also investigated.