In this study, the surface of the ABS substrate was directly electroplated with nickel. The polyaniline-silver composite layer was used as a conductive intermediate layer. To synthesize polyaniline was used three different acids, perchloric acid, nitric acid and sulfuric acid. Fourier Transform Infrared Red (FTIR) and Scanning Electron Microscopy (SEM) instruments have investigated characteristics of synthesized polyaniline. The surface morphology and chemical composition of polyaniline-silver composite was studied by SEM and Energy Dispersive X- ray Spectrometry (EDS). The conductivity of polyaniline, synthesized with different acids and polyaniline-silver composite was measured by four-point probe test. After nickel electroplating on the polymer surface, the coating morphology, thickness of coating, coating adhesion to the substrate by cross-cut test and corrosion properties by cyclic voltammetry and impedance tests have been studied. This study shows the sample synthesized with nitric acid has the finest grain size (1.57 µm) and the highest thickness nickel coating (57 µm). The sample synthesized with sulfuric acid has the lowest electrical resistance (0.008 Ω). In addition, the sample synthesized with perchloric acid has the best adhesion (5B according ASTM standard) and best corrosion properties (polarization resistance equal to 4.87 KΩ and current corrosion equal to 9.73 µA).

In this study, ceramic coatings was produced on pure aluminum in electrolytes containing potassium permanganate by plasma electrolytic oxidation (PEO). The effect of the time of PEO process and changes in the concentration the electrolyte constituents on the structure, corrosion and wear properties was studied. . In the first step, the samples was coated in electrolyte solution containing 15 g/l of potassium permanganate, 3 g/l of sodium carbonate and 6 g/l of calcium carbonate in the time of 1, 5 and 10 minutes. In the second phase the sample was covered in the 9 electrolytic bath that has changed the concentration of any salts at the same time which was 5 minutes. The coatings morpholoy was investigated by Scanning Electron Microscope (SEM) and its chemical composition was studied by X-ray diffraction (XRD). The micro hardness test, electrochemical impedance spectroscopy (EIS), polarization and pin on disk test was performed. The results of the studies showed that the thickness of the coating was between 27-207 µm. XRD analysis of the coatings revealed that components of the coating are MnO, Mn3O4 and Al2O3. The hardness of coatings is increased when the thickness of the coatings was increased uniformly. The greatest hardness was 691/55 HV for the sample which was coated in the solution containing 20 g/l KMnO4. Coating of the aluminum surface increase the corrosion resistance of the sample. Increasing the coating thickness would be increase the corrosion resistance. The lowest corrosion current density was 118.820 nA.cm-2 for the sample that coated in the solution containing 20 g/l KMnO4 and the highest corrosion current density was 507.040 nA.cm-2 for the samples coated in the electrolyte containing 1 g/l Na2SiO3. Increasing the thickness of the coatings improved wear resistance of the samples. The lowest friction coefficient and wear rate around about 0.43 and 3×10-2 mg/N.M related in the case of 20 g/l of potassium permanganate.

 Having proper stability and strength at high temperatures, nickel based superalloys are often used to manufacture many parts of industrial equipment which are used at elevated temperatures. Coating is a suitable method to improve efficiency as well as oxidation and hot corrosion resistance. The present study deals with hot‐dip coating of Inconel 600 superalloy. Samples were dipped in a molten aluminum bath at 750 °C for 7and 15 minutes. Afterwards, samples were heat treated at 450 °C and 550 °C for8, 16 and 24 hours. Microstructures of the coatings were analyzed by both optical and scanning electron microscopy and phase analysis was carried out by X‐ray diffraction tests. Both coated and uncoated samples were subject to cyclic oxidation tests to evaluate their resistance against oxidation at high temperatures. The tests were performed as 15 cycle each consisted of 2 steps: heating at 900 °C for 10 hours and cooling in air. Hot corrosion resistance also was studied by testing at 900 °C for 140 hours in a salt mixture (25% K2SO4+ 75% Na2SO4) on both coated and uncoated samples. Coatings with 101 to 285 μm thickness were observed which were produced due to diffusion of elements from substrate towards the surface and formation of NiAl phases. Microscopic studies, phase determination and weight change of samples during oxidation and hot corrosion tests revealed that Al2O3 and other phases were formed during experiments leading to an increase in weight and consequently improving hot oxidation and hot corrosion resistance. On the other hand, uncoated samples were only observed with weight loss and deterioration during the above mentioned experiments.