Hexavalent Chrome Conversion
Convert toxic hexavalent chrome to non-toxic valences
Coating systems used on aircraft usually contain hexavalent chrome (Cr VI) compounds, such as zinc chromate. Exposure to Cr VI typically occurs during removal of these coatings from aircraft. Cr VI is carcinogenic, and human exposure is strictly regulated by OSHA and the European Union.
Preliminary findings suggest that Lasertronics’ photoablation technology converts this toxic form of chromium into a benign form during the intense energy transfer of the photoablation process.
Background
Chromium can exist in several oxidation states, from -2 to +6 valence. The most important stable states are 0 (elemental metal), +3 (Cr III, “trivalent”), and +6 (Cr VI, “hexavalent”). Many common paint primers employ some form of zinc chromate or calcium chromate, which include Cr VI, hexavalent chrome. These primers are widely used on aluminum, and are nearly universal on aluminum aircraft. Workers who strip these primers using solvents, abrasion, or media blast can be exposed to carcinogenic hexavalent chrome. Exposure limits and disposal of hexavalent chrome are tightly regulated.
In contrast, Lasertronics’ photoablation technology appears to eliminate the danger of worker exposure to hexavalent chrome by converting Cr VI into other valences, such as Cr III. This valence transformation apparently occurs as a byproduct of photoablation during the extremely brief transfer of intense energy to the coating. It renders the chrome harmless to humans and dramatically simplifies disposal of the resulting non-toxic waste products.
This effect was first noticed in 2012. Detailed lab testing is anticipated during 2014 to fully confirm it.
See this white paper on current results: Lasertronics Hexavalent Chrome Conversion