Wear-resistant and low-friction coated piston ring and preparation method therefor

A wear-resistant and low-friction coated piston ring, comprising a piston ring matrix, an outer diameter surface diamond-like carbon coating, and a side surface diamond-like carbon coating, wherein

• the outer diameter surface diamond-like carbon coating on an outer diameter surface of the piston ring matrix comprises, from bottom to top, a first metal interlayer, a second metal interlayer, a gradient diamond-like carbon layer, alternating hardness diamond-like carbon layers, wherein a first hardness diamond-like carbon layer is a high hardness diamond-like carbon layer and a second hardness diamond-like carbon layer is a low hardness diamond-like carbon layer, and an outer running-in diamond-like carbon layer;
• the side surface diamond-like carbon coating on a side surface of the piston ring matrix comprises, from bottom to top, a metal interlayer, the gradient diamond-like carbon layer, and the alternating hardness diamond-like carbon layers,
• wherein in the outer diameter surface diamond-like carbon coating, a thickness of the gradient diamond-like carbon layer is in a range of 0.3 μm to 0.9 μm, a thickness of the alternating hardness diamond-like carbon layers is in a range of 18 μm to 32 μm, and a thickness of the outer running-in diamond-like carbon layer is in a range of 1.5 μm to 4 μm;
• in the side surface diamond-like carbon coating, a thickness of the gradient diamond-like carbon layer is in a range of 0.3 μm to 0.9 μm, and a thickness of the alternating hardness diamond-like carbon layers is in a range of 2 μm to 6 μm.