Mechanically Assisted Electroless Barrel-plating Ni-P Coatings Deposited on Carbon Steel

A mechanically assisted electroless (MAE) barrel-plating technique has been developed to deposit Ni-P coatings on carbon steel.The mechanical treatment was carried out in a rolling drum containing carbon steel specimens and glass balls of 2-3 mm diameter,which was submerged in a bath containing electroless plating solution.The coatings are Ni-polycrystalline and have a fine grained structure and smooth surfaces.The hardness and corrosion resistance of the novel coatings are considerably improved compared with the conventional electroless (CE)-plated Ni-P coatings,which are amorphous.After heat treatment at 400 C for one hour,cracks and pores are observed in the CE-plated Ni-P coating,while no cracks appear in the MAE barrel-plated Ni-P coating.The improved properties of the MAE barrel-plated Ni-P coatings demonstrate the advantages of this novel technique,wide applications of which will be found in industries.