PISTON RING

To provide a high-thermal-conductivity piston ring having excellent scuffing resistance and wear resistance, which can be used in a high-heat-load environment in engines, a TiN coating as thick as 10-60 µm, in which the texture coefficient of a (220) plane is 1.1-1.8 in X-ray diffraction on the coating surface, larger than those of (111) and (200) planes, is formed under the optimized ion plating conditions on a peripheral surface of the piston ring. Also, to obtain excellent sliding characteristics with low friction without losing excellent thermal conductivity of TiN, a hard amorphous carbon coating is formed on the TiN coating.