Rust converter
Rust converters are chemical solutions or primers that can be applied directly to an iron or iron alloy surface to convert iron oxides (rust) into a protective chemical barrier. These compounds interact with iron oxides, especially iron(III) oxide, converting them into an adherent black layer that is more resistant to moisture and protects the surface from further corrosion. They are sometimes referred to as "rust remover" or "rust killer".
Typical ingredients
Commercial rust converters are water-based and contain two primary active ingredients: Tannic acid [1] and an organic polymer. Tannic acid chemically converts the reddish iron oxides into bluish-black ferric tannate, a more stable material.[2] The second active ingredient is an organic solvent such as 2-Butoxyethanol (ethylene glycol monobutyl ether, trade name butyl cellosolve) that acts as a wetting agent and provides a protective primer layer in conjunction with an organic polymer emulsion. Some rust converters may contain additional acids to speed up the chemical reaction by lowering the pH of the solution. A common example is phosphoric acid, which additionally converts some iron oxide into an inert layer of ferric phosphate.[3]
Uses
Rust converter is usually applied to objects which are difficult to sand blast, such as vehicles, trailers, fences, iron railings, sheet metal, and the outside of storage tanks. It may also be used to restore and preserve iron-based items of historical importance.[4]
See also
References
- ↑ "Rust Conversion Mechanism".
- ↑ Binnie, Nancy (April 1992). "Commercial Rust Converters: Surface Protection for Rusted Iron". Canadian Conservation Institute. Retrieved 21 September 2014.
- ↑ Maltby, Susan L. (November 1998). "Rust Converters". Old-House Journal. Retrieved 24 June 2012.
- ↑ National Center for Preservation Technology and Training (June 22, 2010). "Materials Research Program Begins Rust Converter Study". US Department of the Interior. Retrieved 24 June 2012.
External links
- "Comparative Study of Commercially Available Rust Converters"
- "Evaluation of Commercial Rust Converters as a Tool for Corrosion Control" (PDF, 15 MB)
- "The Conservation of Two Cast Iron Bells at the Lac Qui Parle Mission Historic Site" (PDF, 131 kB)