METHOD OF CHEMICAL POLISHING OF ALUMINUM Russian patent published in 1998 - IPC

FIELD: chemical polishing processes. SUBSTANCE: invention relates to chemical polishing of aluminum consisting in treating it by polishing solution, washing, and nitric acid treatment. Samples are preliminarily etched in 50% sulfuric acid, washed with water, clarified by 30% nitric acid, washed by water, and polished for 1-2 min at 80-90 C in solution composed, wt. -%: extraction phosphoric acid, 28.0-28.5; orthophosphoric acid, 28.5-30.0; nitric acid, 3-7; sulfuric acid, 11-16; copper (on conversion to cupric ion), 0.07-0.14; water, the balance. Copper is introduced in the form of sulfate and nitrate. Polished samples are washed out by hot water and treated with 20-30% nitric acid solution to remove passive film and traces of released copper metal. If necessary, polished objects are subjected to anodization. EFFECT: enhanced efficiency of process.