| 摘要 |
<p>According to the present invention, a composite coating containing aluminium and silicon oxides is obtained on the working surface of an engine cylinder (1) and on the bottom of the piston (2) according to a micro-arc oxidation method. The outer porous layer of the coating is removed by a mechanical process so that the coating on the cylinder working surface (6) has a thickness of between 50 and 100 νm and a micro-hardness of at least 15 Gpa. The coating on the bottom (3) of the piston has a higher thickness and a lower micro-hardness. In order to obtain this coating on the part, the method involves generating successive pulses having opposite polarities. The average value of the cathode current is 20 to 40 % higher than the average value of the anode current. The anode voltage amplitude is higher than the mains voltage amplitude, while the cathode voltage amplitude is lower than the mains voltage amplitude.</p> |
