Metal Finishing Guide Book

2013

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25% v/v of 42OBé nitric acid, 6 oz/gal of molybdic acid at 70-150OF (21-66OC). Aqueous solutions of citric acid at 120 to 140OF (49-60OC) may also be evaluated. Note: Comprehensive information describing electropolishing (the anodic brightening and descaling of metals) and use of the Wood's nickel strike are in the chapter titled "Surface Preparation of Various Metal Alloys Before Plating and Other Finishing Applications." ACID TREATMENT OF OTHER METALS AND ALLOYS Aluminum Bright Dipping 1. Nonetch aluminum soak cleaner. 2. Chemically polish in a special acid solution consisting of: 94% v/v of 85% phosphoric acid and 6% v/v of 42OBé nitric acid at 180-185OF (82-85O), until desired surface polishing is achieved. Descaling 1. Nonetch aluminum soak cleaner. 2. 3-5% sulfuric acid or phosphoric acid dip. Neutralizes and conditions the surface. 3. Chemically polish in 15-20% v/v sulfuric acid and 30-40% by wt. of ferric sulfate at 100-140OF (38-60OC). Solution is wetted and specially inhibited. 4. Tarnish inhibit in dip application using a soap (mechanical tarnish inhibit film) or apply on organic topcoat such as a lacquer. Conditioning for Plating Note: Comprehensive information describing aluminum alloys, castings, and suggested deoxidizer/desmutting baths is described in the chapter titled, "Surface Preparation of Various Metal Alloys Before Plating and Other Finishing Applications." Brass and Copper Alloys Descaling—Bright Finish Filter Presses, Clarifiers, Sludge Dryers, Waste Treatment Systems, Evaporators, Bags, Cloth and Media We also buy and sell used equipment www.metchem.com www.metalfinishing.com/advertisers 81

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