[removal of exogenous iron or iron compounds by means of a chemical dissolution]
- • ASTM A967M-13
- • ASTM A380M-13
- • AMS 2700 E
- • QQ-P-35
- • Types II, VI, VIII
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Passivation Services in Orlando
According to ASTM A380, passivation is “The removal of exogenous iron or iron compounds from the surface of stainless steel by means of a chemical dissolution, most typically by a treatment with an acid solution that will remove the surface contamination, but will not significantly affect the stainless steel itself.” In addition, it also describes passivation as “The chemical treatment of stainless steel with a mild oxidant, such as a nitric acid solution, for the purpose of enhancing the spontaneous formation of the protective passive film.”
- no dimensional change
- uniform conversion of existing metal
- decorative coating
- moving oiled parts
- decrease light reflection
- removes impurities
- relieves stress
Passivation process removes “free iron” contamination left behind on the surface of the stainless steel from machining and fabricating. These contaminants are potential corrosion sites that may ultimately result in deterioration of the component if not removed. In addition, the passivation process facilitates the formation of a thin, transparent oxide film that protects the stainless steel from selective oxidation (corrosion).
Passivation Services at A.M. Metal Finishing
- ASTM A967M-13
- ASTM A380M-13
- AMS 2700 E
- Types II, VI, VIII
In the mid 1800s, Christian Friedrich Schönbein discovered that when a piece of iron is placed in dilute nitric acid, it will dissolve and produce hydrogen, but if the iron is placed in concentrated nitric acid and then returned to the dilute nitric acid, little or no reaction will take place. Schönbein named the first state the active condition and the second the passive condition. If passive iron is touched by active iron, it becomes active again.