Abstract: The use of complex fluoride ions of elements of groups 4, 13, or 14 of the periodic table of the chemical elements (preferably selected from complex fluoride ions of the elements B, Si, Ti, and Zr) in concentrations from 30 t 500 millimoles per liter in process solutions for pickling steel or for bleaching and/or passivating pickled surfaces of stainless steel; a process solution for pickling steel or bleaching and/or passivating pickled surfaces of stainless steel comprising: a) one or more strong acids, b) one or more oxidizing agents in the bleaching/passisvating process, c) complex fluoride ions of elements of groups 4, 13 or 14 of the periodic table of the chemical elements in concentrations from 50 to 500 mmoles per liter; replenisher or concentrate containing a combination of active substances thereof; a process for pickling steel or for brightening and/or passivating of pickled surfaces of stainless steel, wherein the surfaces are brought into contact with such a process solution.

Abstract: A method for producing coloured layers on zinc, aluminium, magnesium or alloy surfaces. The surfaces are brought into contact with an aqueous treatment solution which is devoid of chrome, said solution containing, in total, 3-35 g/l persulfate ions and/or peroxodisulfate ions and not more than 10 g/l ammonia or ammonium ions, it has a pH value in the region of between 10-12 and a temperature in the range of between 30-80 ° C. The surfaces are brought into contact with the treatment solution for a period in the region of 0.5-5 minutes and optionally, they are covered with a coating based on organic polymers. The invention further relates to metal parts treated according to said method.

Abstract: An article of manufacture and a process for making the article by the anodization of aluminum and aluminum alloy workpieces to provide corrosion-, heat- and abrasion-resistant ceramic coatings comprising titanium and/or zirconium oxides, and the subsequent coating of the anodized workpiece with a second coating such as polytetrafluoroethylene (“PTFE”) or silicone containing coatings. The invention is especially useful for forming longer life coatings on aluminum substrates by pre-coating the substrate with an anodized layer of titanium and/or zirconium oxide that provides excellent corrosion-, heat- and abrasion-resistance in a hard yet flexible film.