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US 10,294,570 B2Granted
Method for making corrosion resistant coating
AssigneeHamilton Sundstrand Corporation
InventorsMark R. Jaworowski, Blair A. Smith, Georgios S. Zafiris, Weilong Zhang, Michael A. Kryzman, Treese Hugener-Campbell, Bart Antonie van Hassel
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Abstract
A method for making an environmentally-safe chromium based corrosion resistant coating includes pre-treating a metal substrate, immersing the metal substrate in a trivalent chromium bath which does not contain hexavalent chromium, post-treating the coated metal substrate with an oxidizer, and curing the coated metal substrate in a controlled environment.
Claims7
A method comprising:
- pre-treating a metal substrate such that a surface of the metal substrate is de-oxidized;
- immersing the metal substrate in a coating solution to produce a chromium based coating on the metal substrate, wherein the coating solution comprises a trivalent chromium compound and a fluoride compound, but does not contain hexavalent chromium;
- removing the coated metal substrate from the coating solution;
- curing the chromium based coating in a controlled environment containing a gaseous atmosphere to produce a hexavalent chromium enriched corrosion resistant coating on the metal substrate;
- post-treating the coated metal substrate with an oxidizer after removing the coated metal substrate from the coating solution, but before curing the coating;
- and
- exposing the coated metal substrate to ozone in the controlled environment.
4 more elements
A method comprising:
- pre-treating a metal substrate such that a surface of the metal substrate is de-oxidized;
- immersing the metal substrate in a coating solution to produce a chromium based coating on the metal substrate, wherein the coating solution comprises a trivalent chromium compound and a fluoride compound, but does not contain hexavalent chromium;
- removing the coated metal substrate from the coating solution;
- curing the chromium based coating in a controlled environment containing a gaseous atmosphere to produce a hexavalent chromium enriched corrosion resistant coating on the metal substrate, wherein the gaseous atmosphere has a relative humidity of over fifty percent;
- post-treating the coated metal substrate with an oxidizer after removing the coated metal substrate from the coating solution, but before curing the coating, wherein the metal substrate is post-treated with 0.3 wt % to 3.5 wt % hydrogen peroxide solution;
- and
- exposing the coated metal substrate to ozone in the controlled environment.
4 more elements
Dependencies are inferred from the claim text.