COMPOUND FOR PRODUCING HEAT-RESISTANT SEALED INSULATING COATING ON ELECTRIC STEELS Russian patent published in 2004 - IPC

FIELD: electrical engineering; producing coatings on magnetic circuits of electrical machines and apparatuses. SUBSTANCE: proposed compound is produced by adding orthophosphoric acid, urea, ethyl alcohol, and surface-active agent to polyvinyl alcohol aqueous solution at temperature of 65-80 C while continuously stirring it, cooling down to room temperature, adding alkali-alumo-boro-silicate glass in the form of aqueous slurry and chromium oxide (III) prepared in advance. Compound is thoroughly mixed up to attain desired uniformity and applied to electric steel strip, excess compound being removed by means of rubberized roller. Coating is dried out at temperature of 500-600 C for 30-60 s. Considerable domination of inorganic components in compound makes it possible to obtain heat-resistant coating uniform through it thickness. EFFECT: enhanced resistivity of coating which enables welding of coated side surfaces of insulated steel stacks. 1 cl, 1 tbl