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Chromium problems
The document summarizes chromium-free pre-treatment processes for aluminium as alternatives to chromate conversion coatings. It describes several processes including those based on molybdate, permanganate, phosphate, and titanium/zirconium, as well as cerium-based processes, silane treatments, and anodizing. Each process is outlined briefly, noting advantages such as corrosion protection and adhesion, as well as limitations regarding color, thickness, or variability in performance between alloy types. Health, environmental and regulatory concerns with chromate and other hazardous chemicals like hydrofluoric acid are also summarized.
