Method of producing a bohmite layer on etched aluminum foils

Claim 1

A METHOD OF PRODUCING A BOEHMITE LAYER ON AN ETCHED SURFACE OF AN ALUMINUM FOIL INTENDED FOR USE IN ELECTROLYTIC CAPACITORS, SAID BOHEMITE LAYER SERVING TO PROTECT THE SAID SURFACE OF THE FOIL AGAINST CORROSION BEFORE THE FORMATION OF A DIELECTRIC FILM ON THE ETCHED SURFACE, AND SAID BOEHMIC LAYER ALSO SERVING TO FACILITATE THE FORMATION OF THE DIELECTRIC FILM BY REDUCING THE NECESSARY CONSUMPTION OF ELECTRIC POWER IN THE FORMATION OF THE DIELECTRIC FILM, SAID METHOD COMPRISING THE STEPS OF WASHING THE FOIL AFTER ETCHING IN AT LEAST ONE BATH OF DISTILLED WATER AT A TEMPERATURE BELOW 75*C., SUBJECTING THE FOIL IN AT LEAST ONE FURTHER BATH TO THE ACTION OF DISTILLED WATER, THE PH VALUE OF WHICH HAS BEEN ADJUSTED TO A VALUE BELOW 7 AND MAINTAINED AT A VALUE BELOW 7 THROUGHOUT THE TREATMENT, AT A TEMPERATURE WITHIN THE RANGE OF FROM 75*C. TO THE BOILING POINT AT ATMOSPHERIC PRESSURE AND FOR A TIME SUFFICIENT TO OBTAIN A BOEHMITE LAYER OF A THICKNESS OF .04 TO .1 MICRON, AND FINALLY DRYING THE BOEHMITE LAYER AT INCREASING TEMPERATURE INTITALLY NOT EXCEEDING 120*C. AND AT NO TIME NOT EXCEEDING 250*C. UNTIL ITS WATER CONTENT HAS DECREASED TO 20% OR LESS.

Claim 2

A METHOD OF PRODUCING A BOEHMITE LAYER ON AN ETCHED SURFACE OF AN ALUMINUM FOIL INTENDED FOR USE IN ELECTROLYTIC CAPACITORS, SAID BOHEMITE LAYER SERVING TO PROTECT THE SAID SURFACE OF THE FOIL AGAINST CORROSION BEFORE THE FORMATION OF A DIELECTRIC FILM ON THE ETCHED SURFACE, AND SAID BOEHMIC LAYER ALSO SERVING TO FACILITATE THE FORMATION OF THE DIELECTRIC FILM BY REDUCING THE NECESSARY CONSUMPTION OF ELECTRIC POWER IN THE FORMATION OF THE DIELECTRIC FILM, SAID METHOD COMPRISING THE STEPS OF WASHING THE FOIL AFTER ETCHING IN AT LEAST ONE BATH OF DISTILLED WATER AT A TEMPERATURE BELOW 75*C., SUBJECTING THE FOIL IN AT LEAST ONE FURTHER BATH TO THE ACTION OF DISTILLED WATER, THE PH VALUE OF WHICH HAS BEEN ADJUSTED TO A VALUE BELOW 7 AND MAINTAINED AT A VALUE BELOW 7 THROUGHOUT THE TREATMENT, AT A TEMPERATURE WITHIN THE RANGE OF FROM 75*C. TO THE BOILING POINT AT ATMOSPHERIC PRESSURE AND FOR A TIME SUFFICIENT TO OBTAIN A BOEHMITE LAYER OF A THICKNESS OF .04 TO .1 MICRON, AND FINALLY DRYING THE BOEHMITE LAYER AT INCREASING TEMPERATURE INTITALLY NOT EXCEEDING 120*C. AND AT NO TIME NOT EXCEEDING 250*C. UNTIL ITS WATER CONTENT HAS DECREASED TO 20% OR LESS.