Carburizing of low-melting-point metals by pulsed nanocrystalline plasma electrolytic carburizing

This work presents selected results of carbon ion bombardment into 6082 Al alloy substrate by nanocrystalline plasma electrolytic saturation. The carbon ions bombarded with an applied voltage of 400 V in Glycerol based electrolyte and at elevated surface temperature of 400°C. To avoid local surface melting of this alloy, minimum possible duty cycle and maximum frequency were used i.e. 5% for duty cycle and 20 kHz for frequency. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) show the formation of aluminum carbides precipitates with carbon concentrations below their stoichiometric level. The aluminum carbides precipitates have an average grain size in the order of 20–40 nm. Potentiodynamic scanning (PDS) was used to evaluate the corrosion behavior of coatings and it was seen that the treated sample show better corrosion behavior. Also, fretting tribological tests were done and it has been revealed that carbide layer increases the wear resistance of the surface.