Effect of Nitrogen Electrolytes on Al2021 Alloy by Electrolytic Plasma Processing

AlON-Al2O3coatings were prepared on Al2021 alloy by the electrolytic plasma processing (EPP) method. NaNO2, NaNO3and NH4NO3were chosen as nitrogen supply agents. The nitrogen inducing effect was studied by a combined composition and structure analysis of the coating layer carried out by X-ray diffractometer (XRD), scanning electron microscopy (SEM) for the specimens EPP-treated at room temperature for 15 min under a hybrid voltage of 260V DC plus 200V AC (50Hz) power. Microhardness tests and wear tests were carried out to correlate the evolution of microstructure and resulting mechanical properties.