Study the Effects of Carbon Nano Tubes on Corrosion Behavior of Ni-Pelectro-Less Coating of Low Alloy Steels in Salt Water

The basic aim is to study the resistance of corrosion and hardness of heat treatment of coatings with electro-less NiP-CNT. Various concentration of CNTs ranging, 0, 0.1, 0.2 and 0.4g/L in Ni-P-CNT composite was deposited on low alloy steel in electro-less immersion. The Ni-P-CNT electro-less coatings were prepared by using nickel chloride as a source for nickel in the alkaline bath and used CNT. The formulas were characterized with means of EDS, SEM, micro hardness, surface roughness and corrosion measurements. Results of the micro hardness show that hardness higher (560 HV) was achieved for sample (Ni-B-0.1g/l CNT) heat treated. Results enhance that the concentration of CNTs caused the structure of as-coated Ni-P conversion from amorphous to crystalline. Compared to the Ni-P coating, the resistance of corrosion of composite coating (Ni-P-CNT) are better, and they become much better with the increase of the CNT concentration. The addition of CNT makes the coating denser, and the presence of CNT decreases the size of grain to the heat treated formulas but too much CNT deposited on the substrate leads to a high region of the CNT wrapped together and the resulting agglomeration that occur is very unfavorable to coating, resulting in the lead resistance of the corrosion of the composite coating which becomes worse