METHOD OF MAKING HEAT-RESISTANT INSULATING COATS ON ARTICLES MADE FROM ALUMINUM ALLOYS Russian patent published in 2004 - IPC

FIELD: electrochemical oxidation of aluminum and its alloys; instrumentation engineering; electronic industry; manufacture of articles for temperature monitoring and control systems.

SUBSTANCE: proposed method includes treatment of article in three stages: molding the coat in electrolyte containing 2-6 g/l of potassium hydroxide and 10-30 g/l of water glass at voltage of from 400 V and initial density of alternating current 20-25 A/sq dm followed by reduction by 5% every 10 minutes to thickness no less than 100 mcm; then, articles is subjected to treatment at temperature of 200-250 C continued for 1-1.5 h and impregnation in fluoroplastic suspension after which articles are subjected to drying at temperature of 100-150 C. Proposed method makes it possible to increase thickness of coat by 5-7 times, increase break-down voltage by 20-50% at retaining this property at temperature up to 240 C; such thickness of coat enhances resistance of articles to damage during assembly, transportation and in operation.

EFFECT: utilization of electrolyte due to use of agents of lesser toxicity.

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