Used in metal surface treatment processes, particularly for passivation of zinc and zinc-alloy coatings. Provides excellent corrosion resistance by forming a protective oxide layer on the metal surface. Commonly applied in the automotive and electronics industries to enhance the durability of plated components. Also utilized in chromate conversion coatings for aluminum and magnesium parts, improving paint adhesion and providing a barrier against environmental degradation. Due to environmental and health concerns, its use is increasingly regulated, driving the development of safer alternatives.