| 摘要 |
The invention provides for using aqueous solutions, which contain aluminium, zirconium and fluoride and have been adjusted to a pH of </= 5, for rinsing conversion layers produced on surfaces of aluminium or aluminium alloys with solutions based on titanium, zirconium and/or hafnium ions. Preferably, solutions are used for rinsing whose total concentration of Al + Zr + F is between 0.1 and 8.0 g/l, especially between 0.2 and 5.0 g/l, and in which the Al:Zr:F molar ratios have been adjusted to (0.15 to 8.0):1:(5 to 52), especially to (0.15 to 2.0):1:(5 to 16), and with particular advantage to (0.15 to 0.67):1:(5 to 7). Advantageously, the rinsing solutions, which should have a temperature of 20 to 80 DEG C, preferably 20 to 50 DEG C, are applied for a period of 1 to 30 seconds. The process according to the invention is used especially for pretreating the surfaces for subsequent coating, foil coating or adhesive coating. |
