Advanced anticorrosion coatings on lightweight magnesium alloys by atmospheric co2 plasma treatment

Abstract

An improved method for preventing corrosion of magnesium is provided. The method includes providing a magnesium substrate including a native surface layer of nanoporous MgO and Mg(OH) 2 . The method includes generating a CO 2 plasma at atmospheric pressure, flowing the CO 2 plasma from a nozzle exit as a plasma plume, and exposing the surface film to the plasma plume. The method further includes reacting activated CO 2 gas molecules with the native surface layer by performing an atmospheric CO 2 plasma treatment at room temperature to convert at least a portion of the native surface layer of nanoporous MgO and Mg(OH) 2 into a nano-structured to micro-structured MgO/MgCO 3 coating.

1 . A method for preventing corrosion of magnesium, the method comprising:
 providing a magnesium substrate including a native surface layer of nanoporous MgO and Mg(OH) 2 ; and   reacting activated CO 2  gas molecules with the native surface layer by performing an atmospheric CO 2  plasma treatment at room temperature to convert at least a portion of the native surface layer of nanoporous MgO and Mg(OH) 2  into a nano- to micro-structured MgO/MgCO 3  coating.   
     
     
         2 . The method of  claim 1 , wherein reacting activated CO 2  gas molecules with the native surface layer is performed in successive sweeps of a plasma plume. 
     
     
         3 . The method of  claim 1 , wherein the atmospheric CO 2  plasma treatment includes generating a CO 2  plasma at atmospheric pressure, flowing the CO 2  plasma from a nozzle exit as a plasma plume, and exposing the native surface layer to the plasma plume. 
     
     
         4 . The method of  claim 3 , wherein generating the CO 2  plasma includes applying an electrical field to a CO 2  gas feedstock. 
     
     
         5 . The method of  claim 1 , wherein the nano- to micro-structured MgO/MgCO 3  coating comprises a thickness of between 0.1 μm and 10 μm, inclusive. 
     
     
         6 . The method of  claim 1 , wherein the MgO/MgCO 3  coating comprises MgCO 3  with MgO uniformly dispersed therein. 
     
     
         7 . The method of  claim 1 , wherein the magnesium substrate comprises a magnesium alloy. 
     
     
         8 . A method for preventing corrosion of magnesium, the method comprising:
 preparing a magnesium substrate by forming a surface film of nanoporous MgO and Mg(OH) 2 ; and   reacting activated CO 2  gas molecules with the surface film by performing an atmospheric CO 2  plasma treatment at room temperature to convert the surface film of nanoporous MgO and Mg(OH) 2  into a nano-structured to micro-structured MgO/MgCO 3  coating.   
     
     
         9 . The method of  claim 8 , wherein forming the surface film includes distilled water immersion of the magnesium substrate. 
     
     
         10 . The method of  claim 8 , wherein the nano- to micro-structured MgO/MgCO 3  coating comprises a thickness of between 0.1 μm and 10 μm, inclusive. 
     
     
         11 . The method of  claim 8 , wherein reacting activated CO 2  gas molecules with the surface film is performed in successive sweeps of a plasma plume. 
     
     
         12 . The method of  claim 8 , wherein the atmospheric CO 2  plasma treatment includes generating a CO 2  plasma at atmospheric pressure, flowing the CO 2  plasma from a nozzle exit as a plasma plume, and exposing the surface film to the plasma plume. 
     
     
         13 . The method of  claim 13 , wherein generating the CO 2  plasma includes applying an electrical field to a CO 2  gas feedstock. 
     
     
         14 . The method of  claim 8 , wherein the nano-structured to micro-structured MgO/MgCO 3  coating comprises MgCO 3  with MgO uniformly dispersed therein. 
     
     
         15 . The method of  claim 8 , wherein the magnesium substrate comprises a magnesium alloy.