Influence of Heat-Shielding Coatings Formed by Means of Anodic Micro-Arc Oxidation on the Service Life Characteristics of Piston Engines

The temperature field of the parts of the cylindrical-piston group and the stress-deformed state of the piston are analyzed. It is shown that the performance characteristics of the group of parts of the cylinder and piston may be improved, above all, by creating heat-shielding coatings on its working surfaces to equalize the heat stress gradient and thus reduce the likelihood that microcracks might form. Shielding coatings that have been created on the piston crown for a two-stroke engine, for example, must withstand thermocyclical stresses on a flat surface of up to 100 MPa and on a concave surface, stresses of up to 273 MPa, at a warm-up temperature of 673 °C, and not disintegrate under the pressure of gases producing normal mechanical stresses reaching 4.5 MPa. It is established that ceramic oxide coatings created on the piston crown by means of anodic micro-arc oxidation satisfy the heat shielding requirements for engine parts under the effective thermocyclical loads.