ASTM A380
Specifications
Technical Notes
Definition
Passivation is removal of exogenous iron or iron compounds from the surface of a 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
How it works
Passivation is the chemical treatment of a stainless steel with a mild oxidant, such as a nitric acid solution, for the purpose of enhancing the spontaneous formation of the protective passive metal oxide film.
Descaling
Descaling removes a buildup of oxide film caused by thermal action (welding, high temp baking etc). Descaling must be removed prior to passivation. Descaling methods are either chemical (Pickling) or mechanical (grinding, blasting).
.png)
Ready to get started?
Talk to an industry expert about the best solution for your application.
Resources
AOTCO Acquires Modern Metal Finishing
Archeological Discovery Shows AOTCO’s History of Metal Plating
AOTCO Launches New Type I Chromic Acid Anodizing Line
Services & Capabilities

Electroplating
Electroplating
Electroplating is a process by which one metal is deposited onto a base metal (substrate). These deposited metals offer a variety of benefits including thermal and electrical conductivity, corrosion resistance and more. AOTCO electroplates a wide variety of both standard and exotic metals.
Learn More
Anodizing
Anodizing
Sometimes called a “conversion coating” Anodizing is an electrolytic process in which an oxide (anodic) layer is chemically built on the surface of the substrate material, providing anti-corrosion and other benefits. AOTCO offers, Type I, Type 2, Type 3 and Titanium anodizing services.
Learn More
Passivation
Passivation
Passivation is a term for a variety if processes that make a metal (most commonly stainless steel) or other substance unreactive, or passive, by altering the surface layer or coating the surface with a thin inert layer. AOTCO performs both citric and black oxide passivation techniques to a range of specifications.
Learn More
Plating Substrates
Plating Substrates
AOTCO plates on a wide variety of Common, Exotic and Non-Metallic substrates, bringing exceptional expertise to magnesium, titanium, beryllium, BeCu, TeCu, tungsten and more. In some cases we pass as high as 450 degrees celsius, allowing for high temperature soldering, brazing, or post machining operations after plating.
Learn More
Pre- & Post-Process Treatments
Pre- & Post-Process Treatments
Pre-Process: In addition to offering both mechanical & chemical cleaning options, AOTCO specializes in creating solutions for complicated, difficult and tight-tolerance masking challenges. Post-Process: For clients with specialized needs AOTCO offers laser marking and engraving options, including color change caused by chemical or molecular changes, charring, foaming, melting, ablation, and more.
Learn More
Dedicated Outsourced Finishing
Dedicated Outsourced Finishing
Part of our cornerstone goal of building long-term, collaborative & solution-oriented partnerships, AOTCO will devote reserved physical and human resource capacity for our clients with long-term finishing and deadline requirements. For these partnerships our commitment is that AOTCO manages the process, while YOU control the results.
Learn More