| 摘要 |
<p>The invention relates to the production of wear-resistant coatings on the surface of metals by micro-arc oxidation. The thin-layer ceramic coating consists of fibrous alpha-Al2O3 crystals with a cross-sectional dimension of ~100 nm, which are situated in a finely-crystalline matrix of gamma-Al2O3 and mullite 3Al2O3-2SiO2. The coating is characterized by the load-bearing capacity of the surfaces of friction pairs with an aqueous lubricant and with a low-hydrocarbon lubricant, wherein the pressure in the friction pair is P > 150 kg/cm2. The method for producing the coating includes oxidation at a ratio of Ic/Ia = 1.0-1.15 for 90-240 min. in two successive electrolytes. Oxidation is carried out in the second electrolyte with periodic pulsing at 30%-50% of the set steady-state current. The friction surface is formed by fibrous alpha-Al2O3 crystals which partially extend immediately beyond the limits of the finely-crystalline matrix of gamma-Al2O3 and mullite 3Al2O3-2SiO2. The method for producing a friction surface includes treatment with an abrasive, the strength of which is greater than the strength of the substrate and of the fibrous alpha-Al2O3 crystals in the transverse direction, but less than the strength of the fibrous crystals in the longitudinal direction. The invention increases the load-bearing capacity of the coating and of the friction surface based thereon.</p> |
