Dutch
- alodineren
- alodiniseren
- chromateren
English
- chromate conversion coating
- chromate treatment
- alodine coating
- Alocrom treatment
- chromate passivation
- chromate
Wikipedia (nl)
Chromateren is een chemische bewerking van een metaaloppervlak waarbij een chromaatlaag (conversielaag) ontstaat en is een vorm van passiveren. Chromateren is iets anders dan verchromen. Chromateren kan worden toegepast op verschillende metalen, waaronder aluminium, koper, magnesium, staal, tin, zilver en zink. De chromaatlaag fungeert als corrosieremmer, heeft een goede elektrische geleidbaarheid, en geeft een glimmende afwerking. Een typische laagdikte bij chromateren van aluminium gaat tot ongeveer 1 µm.
Wikipedia (en)
Chromate conversion coating or alodine coating is a type of conversion coating used to passivate steel, aluminium, zinc, cadmium, copper, silver, titanium, magnesium, and tin alloys. The coating serves as a corrosion inhibitor, as a primer to improve the adherence of paints and adhesives, as a decorative finish, or to preserve electrical conductivity. It also provides some resistance to abrasion and light chemical attack (such as dirty fingers) on soft metals.
Chromate conversion coatings are commonly applied to items such as screws, hardware and tools. They usually impart a distinctively iridescent, greenish-yellow color to otherwise white or gray metals. The coating has a complex composition including chromium salts, and a complex structure.
The process is sometimes called alodine coating, a term used specifically in reference to the trademarked Alodine process of Henkel Surface Technologies.
[...]
As of 1995, Henkel's Alodine 1200s commercial formula for aluminum consisted of 50-60% chromic anhydride CrO3, 20-30% potassium tetrafluoroborate KBF4, 10-15% potassium ferricyanide K3Fe(CN), 5-10% potassium hexafluorozirconate K2ZrF6, and 5-10% sodium fluoride NaF by weight. The formula was meant to be dissolved in water at the concentration of 9.0 g/L, giving a bath with pH = 1.5. It yielded a light gold color after 1 min, and a golden-brown film after 3 min. The average thickness ranged between 200 and 1000 nm.[6]
Iridite 14-2 is a chromate conversion bath for aluminum. Its ingredients include chromium(IV) oxide, barium nitrate, sodium silicofluoride and ferricyanide.[12] In the aluminum industry, the process is also called chemical film[13] or yellow iridite,[13] Commercial trademarked names include Iridite[13] and Bonderite[14] (formerly known as Alodine, or Alocrom in the UK).[15] The main standards for chromate conversion coating of aluminium are MIL-DTL-5541 in the US, and Def Stan 03/18 in the UK.
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