The reliability and durability of the piston–cylinder groups (PCG) of internal-combustion engines strongly depend on the dimensions of the clearance in the “piston ring–piston groove” joint whose limiting state leads to the fracture of the ring and failure of the engine. The increase in the clearance can, in fact, be regarded as the superposition of molecular, abrasive, and corrosion wear. The maximum wear is observed at the lower ends of the ring and the groove. For pistons made of cast iron, the degrees of wear of the ring and the groove are almost identical. At the same time, for aluminum pistons, the degree of wear of the joint is almost three times higher than for cast iron and the degree of wear of the harder end surface of the ring made of cast iron constitutes 70% of the total wear [1, 2]. In view of the world trend of boosting the engines, this problem becomes especially urgent and explains the extensive search of new methods aimed at increasing the wear resistance of the end surfaces of the rings [3, 4]. Since the deposition of electroplated chromium coatings (used on the working surface of the upper compression rings) on the end surfaces would lead to a severalfold increase in the laboriousness of their production, it is reasonable to study the electrophysical methods of surface hardening. The aim of the present work is to analyze the influence of the electric-spark alloying (ESA) and cathodic ion bombardment (CIB) of the end surfaces of cast-iron piston rings on their wear resistance under the conditions of molecular and abrasive wear.