Pilot D-300 Concentrate

D-300 CONCENTRATE is a 50% aqueous solution of 4-sulfophthalic acid containing small amounts of sulfuric acid. D-300 CONCENTRATE is the primary component of the preferred electrolyte to produce the "hard" anodic oxide coatings on aluminum and aluminum-based alloys. Such coatings, in addition to being highly abrasion resistant, are colored in metallic gray, brownish gray, black, bronzes, gold and dark brown colors, which are attractive for architectural and other uses of aluminum. The colors obtained with theD-300 CONCENTRATE process depend on the base metal composition, current density, voltage, film thickness and electrolyte composition, particularly the sulfate and aluminum contents. It is necessary to control all these factors carefully to obtain a consistent color in the finished product.