Abstract The characterization of aluminum particulates charging in a coating cell on the morphology and corrosion behavior of nickel aluminum composite coating by an electro-chemical co-deposition coating were evaluated. The aluminum reinforced nickel matrix composite coatings were co-deposited on Austenitic Stainless Steel (316 L) workpieces by a nickel-ion electrolytic solution firmly postponed with -10 µm max. diameter aluminum particulates. The extreme limit of co-deposited aluminum can occur at a particulate gratified of 50 g/l in the cell, a current density of 4.5 A/dm2, a PH of 4.0 – 4.1, and a circulation rate of 400 rpm. Entirely co-deposited specimens were heat-treated under a vacuum atmosphere for five hours at 950 °C prior to Potentiostatic testing. Throughout heat treatment, coating morphological development was initiated to occur by the exothermic reaction nickel +aluminum = nickel aluminum. Surface morphology was inspected by scanning electron microscopy(SEM) and X-ray diffraction (XRD) and atomic absorption. Furthermore, The electrochemical enactment of the coatings was considered by the Potentiostatic test in 3.5wt.% NaCl. It originated that, a combination of aluminum particulates in nickel matrix sophisticated the nickel grains coatings. Though polarization curves raised to negative potentials, and the rate of corrosion is reduced.

Conclusions: The extent of aluminum co-deposited particulates into a nickel base rise as the extent of particulates in the cell is increased. A maximum quantity of co-deposited particulates is gotten at cell loading of 50 grams per liter and deposition current density of 4.5 A/ dm2. Codeposition of aluminum particulates into a nickel matrix products coating with an even distribution of particulates.
1) Conferring to the atomic absorption test, the maximum aluminum content in the coating was 28 wt.%. when the concentration of aluminum particulates is 50 g/liter.
2) Heat treatment at 950 oC for 5 hrs. under argon atmosphere outcomes in diffusion-reaction between the aluminum particulates and nickel matrix to produce a nickel aluminide intermetallic compound.
3) Increasing Aluminum metal particulates in coated specimens moved polarization curves to negative potentials and the corrosion rate is decreased.
4) Maximum improvement is 97% and the minimum corrosion rate is (0.0643*10-3 ) mpy in 3.5%NaCl solution when the concentration of Al is 50 g/liter in the coating solution.