Passivation is a corrosion prevention method used on metal alloys that are usually fairly corrosion-resistant to begin with, like stainless steel. Passivation is used on aluminum, zinc, titanium, silicon, and iron-based alloys. The passivation process is known to be used more frequently by the medical, electronics, and aerospace industries. Though pure aluminum naturally has almost the same corrosion resistance as other metals with a passivation layer, aluminum alloys without passivation (or anodization) have almost no protection from harsh environments.
Passivation is a crucial measure to get the most resistance to the weathering of components machined from stainless steel or aluminum. The key to the passivation process for stainless steel is a microscopically thin layer of oxide film across its surface which provides the necessary means to ensure protection from oxidation (corrosion).
Passivation almost always begins with a very thorough cleaning of the materials that will be passivated. A common method of cleaning and degreasing involves the use of solvent cleaners and alkaline soaking. After the necessary cleaning measures have been taken, the object is ready to be placed in the appropriate passivation solution. This is typically done with a nitric-acidic-based solution. A comprehensive understanding of the material types and passivation processes is paramount to successfully achieving the desired results. To find more information on the standard practice for cleaning, descaling, and passivation of stainless steel, you can download a copy of ASTM A380.*
Express Barcode Labels not only offers passivated stainless steel products, but also specializes in the passivation of aluminum alloys through a process called anodization. Anodizing aluminum is an electrolytic passivation process which adds an outer coating of aluminum oxide to the raw material as a first measure of corrosion protection. Anodizing increases the corrosion and wear resistance of the aluminum, while providing better adhesion for paint primers and glues beyond just bare metal. When it comes to asset tags and barcode labels, most people choose anodized aluminum for its added abrasion and chemical resistance. The anodized aluminum labels and tags are produced to last the lifetime of its use in any environment that comes into contact with chemicals, heat, abrasion, or harsh weather.
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