A slurry of aluminum and silicon metal powders in a chromate/phosphate binder designed to be used to aluminize cobalt- and nickel-alloys. After being applied and heat cured, Alseal 625 must be annealed above 1600oF (870oC) in a vacuum or inert atmosphere. The resulting silicon-modified aluminide is uniquely resistant to both low temperature and high temperature hot corrosion (Types 1 and 2 sulfidation), as well as oxidation, up to 1800oF (982oC) and above. Alseal 625 also provides a very wear resistant and heat oxidation resistant surface.
An aluminum-ceramic most often used to limit corrosion below 1100oF (593oC), it can also be used for slurry aluminizing in the same way as Alseal 625. Unlike Alseal 625, Alseal 518 contains no silicon metal. Unmodified aluminides produced from this slurry are less brittle than aluminides formed from Alseal 625, but they are not as resistant to hot corrosion.