- The final step in the anodic oxidation is the sealing of the porous surface. For this purpose, two processes can be used, cold sealing and hot sealing. During the cold sealing process, nickel and aluminium salts are taken up in the pores and products such as Alfiseal 982 (liquid) are used. During the hot sealing process, the pore is sealed by swelling and products such as Alfiseal 942 (avoids “fingerprints”) or Alfiseal 934 (for tap water or demineralised water) are used. There is also a mid-temperature sealing available. A special combination of Alfiseal 982/5 (cold sealing) and Alfiseal 961 (hot sealing) allows to get an improved alkaline resistance (asked by automotive industry) on anodized aluminium substrates.
