Metal Finishing Guide Book

2013

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metals, owing to variations. It has good potential in industrial applications, as well as for brightening and smoothing; however, results are not consistent because of great variations in composition and surface conditions from mills and/or heat treatment. R. Delaplace and C. Bechard Pyrophosphoric acid, 400 g Ethyl alcohol to make 1 L Temperature, 20¡F Current density, 300 A/ft2 Cooling of the electrolyte is required, and water must be absent. C. Faust Sulfuric acid, 15% Phosphoric acid, 63% Chromic acid, 10% Current density, 50-1,000 A/ft2 Temperature, 125¡F This solution has a finite life. Weisberg and Levin Lactic acid, 33% Phosphoric acid, 40% Sulfuric acid, 15.5% Current density, 100 A/ft2 Temperature, 65-90¡F Polishing rate is quite low; 1-2 hr are required. Hammond, Edgeworth, and Bowman Phosphoric acid, 55-85% Trialkali metal phosphate, 1-15% Alkali metal sulfate, 0.5% minimum Stainless Steel Stainless steel is the most popular electropolished metal today. It retains its finish, and no aftertreatment is required. H. Uhlig Phosphoric acid and glycerine, 90% Glycerin, >50% Current density, >20 A/ft2 Temperature, >200¡F J. Ostrofsky Citric acid, 55% Sulfuric acid, 15% Current density minimum, 100% A/ft2 Temperature, 200¡F This solution freezes below 130¡F. Alcohol is recommended to reduce the freezing point. C. Faust 89

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