GLENAIR
Many effective protective coatings utilized in the interconnect industry employ a combination of two or more finish materials in order to create a physical barrier between joining parts and to prevent galvanic corrosion due to dissimilar metals. The approved U.S. Navy finish, chromated cadmium over electroless nickel, is the most common finish of this type provided by Glenair. Other choices include chromated zinc-nickel and tin-zinc Passivation Stainless steel parts require a special finish treatment known as “passivation.” The chromium content of stainless steel causes the natural formation of an invisible, corrosion-resisting chromium oxide film on the steel surface. If damaged mechanically or chemically, this film is self healing as long as oxygen is present. The protective quality of this oxide film layer can be enhanced by passivation. 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 that will remove the surface contamination, but will not significantly affect the
Passivated stainless steel finish on a PowerLoad plug (top) and a pressure- boundary firewall feed- thru (bottom)
stainless steel itself.” The ASTM spec goes on to describe 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.” Passivation removes “free iron” contamination left behind on the surface of the stainless steel from casting, machining, and other secondary operations. These contaminants are potential corrosion sites if not removed. Anodization Anodizing is an electrolytic process that places aluminum oxide films on aluminum. The resulting coating is uniform, much harder, and denser than natural oxidation. It is formed by converting the surface of the part with a simultaneous penetration and build-up of aluminum oxide. Unlike paint, which can flake off if not applied properly, anodized finishes are actually formed from the base material and cannot flake off. The aluminum oxide finish is very hard and exceptionally wear resistant. The aluminum can also be dyed at the end of the anodizing process for a colored finish. Anodized parts are non-conductive. Electrodeposited Paint or Electroplating Electrodeposited paint, also referred to as electrocoating, electrophoretic deposition, or electropainting, is an organic finishing process that uniformly applies thin-film primers and one-coat finishes to metallic substrates. Electrodeposited paint resembles electroplating by using electric current to deposit a coating onto substrates. However, electrocoating deposits waterborne paint onto substrates rather than metal ions.
Because of the uniformity of the applied coating, and excellent adhesion properties, corrosion protection offered by electrodeposited paint is quite high on both steel and aluminum substrates. Corrosion testing performed by the National Defense Center for Environmental Excellence (NDCEE) has demonstrated exceptional performance when used as a primer in combination with both aerospace and chemical agent resistant coating (CARC) topcoats. Electrodeposited paint also offers reduced environmental impact associated with hazardous solvents, and solid/hazardous waste generation and disposal. Glenair offers black electrodeposited paint finish on signal and power connection products such as the ITS connector series, based on MIL-DTL-5015 with reverse bayonet and threaded coupling options, and the IPT-SE connector series based on MIL-C-26482. Electrodeposited paint can also be specified for other Glenair products.
A pair of ITS 500 single-pole high current connectors with black electrodeposited paint finish
QwikConnect • April 2023
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