SHORT-TERM HEAT-SEALING OF ANODIZED METAL SURFACES WITH SURFACTANT-CONTAINING SOLUTIONS

摘要

PURPOSE: An improved method is provided to post-seal for improving an anodized porous coat being generated electric-chemically. CONSTITUTION: Described is a method of sealing anodized metal surfaces, the method being characterized in that the anodized metal is brought in contact, for a length of time between 0.5 and 2 minutes per micrometer of anodized-layer thickness, with an aqueous solution having a temperature between 75°C and the boiling point and a pH in the range 5.5 to 8.5 and containing:a) a total of 0.0004 to 0.05 g/l of one or more cationic, anionic or non-ionic surfactants; and b) a total of 0.0005 to 0.5 g/l of one or more organic acids selected from the group comprising the cyclic polycarboxylic acids with 3 to 6 carboxyl groups and the phosphonic acids. The preferred surfactants are non-ionic surfactants and the preferred acids are polyphosphinocarboxylic acids. Optionally present are alkali-metal and/or alkaline-earth metal cations, preferably Li and/or Mg ions, in amounts of 0.0001 to 5 g/l.