Yellow Passivation / Yellow Chromate

Yellow passivation (also yellow chromate) refers to a yellow-gold chromate conversion coating on zinc or zinc alloy coatings. It is formed by treating the zinc surface in a chromate solution and produces a characteristic yellow, iridescent appearance combined with enhanced corrosion protection compared to bare or clear-passivated zinc. Historically, chromium(VI)-containing chromates were often used for this; modern systems increasingly rely on trivalent, chromium(VI)-free alternatives with a similar color tone and protective effect. In the automotive sector, yellow passivation is mainly used for fasteners and fixing elements where both a defined appearance and corrosion resistance are required.