Abstract: An alternator includes a housing and a rotary shaft. The alternator includes one or more brushes supported by the housing. The alternator includes a slip ring assembly coupled to the rotary shaft for rotating with the rotary shaft. The slip ring assembly includes one or more slip rings. The one or more slip rings include a body portion defining an outer surface. The one or more slip rings also include an oxide layer disposed on the outer surface of the body portion. The oxide layer is non-uniform. The oxide layer is formed on account of a thermal oxidation process of the one or more slip rings during an operation of the alternator. Further, the thermal oxidation process for formation of the oxide layer initiates when an operating temperature of one or more components of the alternator lies within a predetermined temperature threshold range.