| 摘要 |
The proposed invention relates to the sphere of plasma electrolytic oxide coating of aluminium alloys. The method incorporates anode-cathode oxide coating in an alkaline electrolyte at a temperature of 15-50 DEG C, using 50-60 Hz frequency alternating current. In the initial stage of the process oxide coating is carried on for 5-90 seconds at a current density of 160-180 A/dm<2>, then the current density is dropped to 3-30 A/dm<2> and the process is continued in a regimen of spontaneous diminution of power demand without on-line adjustment of the regimen until the set coating thickness is achieved. The alkaline electrolyte used is an aqueous solution of alkaline metal hydroxide at 1-5 g/l, an alkaline metal silicate at 2-15 g/l, an alkaline metal pyrophosphate at 2-20 g/l and peroxide compounds at 2-7 g/l (in terms of H2O2 - 30%). The proposed method enables the protective properties of ceramic oxide coatings to be enhanced through an increase in the micro-hardness, density and strength of adhesion to the substrate without any additional energy outlay or time required. |
