| 摘要 |
FIELD: metallurgy. ^ SUBSTANCE: invention refers to electroplating. The procedure consists in micro-arc oxidation (MAO) during 55-85 min in solutions containing caustic potassium, boric acid and methylene blue at density of current 25Ç35 A/dm2. Parts are transferred and oxygen is supplied to their surface. Laser radiation is applied to a jet of oxygen at distance of 1-2 mm off oxidised surface. Further parts are heated. Also prior to MAO, solutions are heated to 70Ç80C, mixed and cooled to 15Ç20C. MAO is performed in four stages: during 10 min in solution of caustic potassium 6Ç8 g/l, boric acid 40Ç50 g/l and methylene blue 0.5Ç0.8 g/l, further 15Ç20 min in solution of caustic potassium 6Ç8 g/l, boric acid 40Ç50 g/l, methylene blue 0.5Ç0.8 g/l, corundum (3Ç5 mcm) 40Ç60 g/l and chromium oxide 1Ç2 g/l, then 20Ç30 min in solution of caustic potassium 6Ç8 g/l, boric acid 40Ç50 g/l, methylene blue 0.5Ç0.8 g/l corundum (5Ç7 mcm) 40Ç60 g/l and chromium oxide 1Ç2 g/l, and finally in solution of caustic potassium 6Ç8 g/l, boric acid 40Ç50 g/l, methylene blue 0.5Ç0.8 g/l corundum (7Ç10 mcm) 40Ç60 g/l and chromium oxide 1Ç2 g/l. Further parts are heated to 380Ç400C, and conditioned during 25Ç30 min at gradual drop of pressure 10Ç30 Pa at rate 3500Ç4000 Pa/min. ^ EFFECT: decreased power consumption, increased efficiency, thickness, hardness, breakdown voltage and electrical resistance of produced coating. ^ 2 tbl, 6 dwg, 1 ex |
