Effect of H₃BO₃ on the Corrosion Properties of Ni-B Based Electroplating Coatings

In this study the effect of H₃BO₃ on the properties of Ni-B coating formed on the AISI 1020 steel surface produced with electroplating process was investigated. Synthesis of the coatings was done using acidic electro plating bath. Coating process was carried out within a standard cell with three electrode system using platinum as auxiliary and Ag/AgCl electrode as a reference electrode onto AISI 1020 steel substrate. Then, heat treatment was applied to coatings at 400°C during a period of 1 h. The coated samples were analyzed by optical microscope, scanning electron microscope, and X-ray diffraction. Micro hardness measurements of the coatings were realized. The study reveals that the Ni-B anti corrosion coating is amorphous in their as-plated condition and upon heat treatment at 400°C for 1 h, Ni-B coatings crystallize and produce nickel borides and nickel in the coatings. The results indicated the presence of Ni₂B, Ni₃B and Ni phases.