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Composition solution for mirror finish aluminum sheet

Hits: 8803  •  Add time2019-08-28 16:23:15, author:Haomei Aluminum Plate

  The chemical polishing of mirror finish aluminum sheet usually adopts a 70% (mass percent) phosphoric acid based solution. The most commonly used is a mixture of phosphoric acid, nitric acid and sulfuric acid. When the composition of the alloy changes, the sulfuric acid content (mass percentage) is 9%. The change between l5% and the nitric acid content (% by mass) varies between 3% and 9%. Since the working temperature is around 105 °C, a large amount of nitrogen oxides are generated to pollute the environment. Therefore, based on the phosphoric acid and sulfuric acid mixture, the S-type copper brightener is used as an additive to produce a yellow-free chemical polishing process. However, this yellow-free chemical polishing is only suitable for pure aluminum or aluminum-magnesium alloys, like 1050, 1060, 1070, 1100 or 3105 aluminum sheet, and its effect is inferior on other aluminum alloys. Later, there was a formula with only 2% nitric acid, and similar additives were used, which did not expand the scope of application. However, the phosphoric acid, nitric acid, and sulfuric acid mixed solutions are still in the mainstream formulation because of their strong adaptability.

   For polishing of aluminium sheets with high copper and zinc, it is helpful to add 2~5g/L chromic anhydride during chemical polishing. The manual contains a high-silicon-containing aluminum mirror sheet pieces. For chemical polishing, a mixture of 60-65 mL/L nitric acid, 15-20 mL/L hydrofluoric acid, and glycerin 1-2 mL/L is immersed for 2 s at room temperature. However, this method is more like etching. 
  There is also a formulation containing acetic acid for pure aluminum and 2A12 (LYl2), which contains phosphoric acid 850ml/L, glacial acetic acid 100ml/L and nitric acid 50ml/L at the of temperature from 80 to 100 ° C. The polishing time lasts 2 to 5 minutes. Acetic acid has a better effect on preventing pitting corrosion of the mirror finish aluminum sheet.

Tagged:mirror finish aluminum sheet, aluminum mirror sheet, aluminum sheet


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