Methods for Reducing Hexavalent Chromium in Trivalent Chromate Conversion Coatings
OwnerJoseph Kuezynski, Kevin A. Splittstoesser +2inventors
InventorsJoseph Kuezynski, Kevin A. Splittstoesser, Timothy J. Tofil, Paul A. Vermilyea
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Abstract
The present invention is directed to trivalent chromate conversion coatings for plated metals, and more particularly, to methods for reducing hexavalent chromium in trivalent chromate conversion coatings. In one embodiment, such method includes placing a metal article having a trivalent chromate conversion coating in a reducing solution. The trivalent chromate conversion coating includes hexavalent chromium and the reducing solution including a reducing agent, which reduces the hexavalent chromium so as to reduce or eliminate the hexavalent chromium on the plated metal article.
Claims24
A method for reducing hexavalent chromium in a trivalent chromate conversion coating comprising:
- placing in a reducing solution a metal article having a trivalent chromate conversion coating, the trivalent chromate conversion coating including hexavalent chromium and the reducing solution including a reducing agent, wherein the reducing agent reduces the hexavalent chromium.
A method for reducing hexavalent chromium in a trivalent chromate conversion coating comprising:
- immersing a metal article in a trivalent chromium solution to apply a trivalent chromate conversion coating to the metal article;
- removing the metal article from the trivalent chromium solution, the metal article including the trivalent chromate conversion coating;
- placing in a reducing solution the metal article having the trivalent chromate conversion coating, the trivalent chromate conversion coating including hexavalent chromium and the reducing solution including a reducing agent;
- and
- reducing the hexavalent chromium in the reducing solution to trivalent chromium by reacting the hexavalent chromium with the reducing agent.
A method for reducing hexavalent chromium in a trivalent chromate conversion coating comprising:
- applying a trivalent chromate conversion coating to a metal article;
- placing in a first reducing solution the metal article having the trivalent chromate conversion coating, the trivalent chromate conversion coating including hexavalent chromium and the first reducing solution including a first reducing agent, wherein the first reducing agent reduces the hexavalent chromium;
- drying the metal article;
- and
- placing in a second reducing solution the metal article having the trivalent chromate conversion coating which includes additional hexavalent chromium, the second reducing solution including a second reducing agent, wherein the second reducing agent reduces the additional hexavalent chromium.
Dependencies are inferred from the claim text.