ASTM B 373

This specification covers nine thicknesses of annealed aluminum foil for use in manufacture of capacitors and includes UNS alloy designations A91145 and A91235. Foil to be used as anodes in electrolytic capacitors is beyond the scope of this specification. Requirements for quality assurance, chemical analysis, and tensile breaking load test are detailed. The foil shall conform to the chemical composition requirements prescribed for aluminum, silicon and iron, copper, manganese, magnesium, zinc, vanadium, and titanium, and shall meet the specified requirements for tensile breaking load, direct current electrical resistance, and area per unit weight. The foil shall be supplied with the finish bright on one side and matte on the other, in the dry or slick condition (dry annealed A, dry annealed B, dry annealed C, or slick annealed) and shall be tested for surface condition by water or water-alcohol test. Spooling requirements such as roll dimensions, roll winding, and roll covering are given. Foil splices shall be either welded or knurled and shall be free of splits, slivers, wrinkles, ragged edges, or excessive pinholes.