Systems and methods for treating a substrate

Abstract

Disclosed herein is a system for treating a magnesium or a magnesium alloy substrate comprising: a first pretreatment composition comprising a fluorometallic acid and free fluoride in an amount of 10 ppm to 500 ppm based on total weight of the first pretreatment composition and having a pH of 1.0 to 4.0; and a second pretreatment composition comprising a lanthanide series metal, the second pretreatment composition being substantially free of peroxide. Also disclosed are methods of treating a magnesium or magnesium alloy substrate. Treated magnesium and magnesium alloy substrates also are disclosed.

1 . A system for treating a magnesium or a magnesium alloy substrate comprising:
 a first pretreatment composition comprising a fluorometallic acid and free fluoride in an amount of 10 ppm to 500 ppm based on total weight of the first pretreatment composition and having a pH of 1.0 to 4.0; and   a second pretreatment composition comprising a lanthanide series metal, the second pretreatment composition being substantially free, or essentially free, or completely free, of peroxide.   
     
     
         2 . The system of  claim 1 , wherein the fluorometallic acid comprises a metal comprising a Group IIIA metal, a Group IVA metal, a Group IVB metal, and/or a Group VIII metal. 
     
     
         3 . (canceled) 
     
     
         4 . The system of  claim 2 , wherein the fluorometallic acid comprises the metal in an amount of 10 ppm to 2,000 ppm based on total weight of the first pretreatment composition. 
     
     
         5 . The system of  claim 1 , wherein the first pretreatment composition further comprises a hydroxide source and/or a fluoride source in addition to the fluorometallic acid. 
     
     
         6 - 7 . (canceled) 
     
     
         8 . The system of  claim 1 , wherein the second pretreatment composition comprises the lanthanide series metal in an amount of 5 ppm to 25,000 ppm based on total weight of the second pretreatment composition. 
     
     
         9 . The system of  claim 1 , wherein the second pretreatment composition further comprises a Group IIIA metal and/or a urea. 
     
     
         10 . The system of  claim 9 , wherein the second pretreatment composition comprises the Group IIIA metal in an amount of 10 ppm to 500 ppm based on total weight of the second pretreatment composition and/or the urea in an amount of 20 ppm to 500 ppm based on total weight of the second pretreatment composition. 
     
     
         11 . The system of  claim 1 , further comprising a cleaner composition. 
     
     
         12 - 13 . (canceled) 
     
     
         14 . The system of  claim 1 , further comprising a film-forming composition. 
     
     
         15 . (canceled) 
     
     
         16 . A method of treating a magnesium or a magnesium alloy substrate comprising:
 contacting at least a portion of a substrate surface with a first pretreatment composition comprising a fluorometallic acid and free fluoride in an amount of 10 ppm to 500 ppm based on total weight of the first pretreatment composition and having a pH of 1.0 to 4.0; and   contacting at least a portion of the substrate surface with a second pretreatment composition comprising a lanthanide series metal and being substantially free, or essentially free, or completely free, of peroxide.   
     
     
         17 . The method of  claim 16 , wherein the fluorometallic acid comprises a metal comprising a Group IIIA metal, a Group IVA metal, a Group IVB metal, and/or a Group VIII metal. 
     
     
         18 . The method of  claim 16 , further comprising contacting at least a portion of the substrate surface with a cleaner composition prior to the contacting with one of the pretreatment compositions. 
     
     
         19 . The method of  claim 16 , further comprising contacting at least a portion of the substrate surface with a coating composition comprising a film-forming resin following the contacting with the pretreatment compositions. 
     
     
         20 . The method of  claim 16 , wherein the contacting with the second pretreatment composition comprises a spontaneous contacting. 
     
     
         21 . The method of  claim 16 , wherein the contacting with the second pretreatment composition comprises passing an electric current between an anode and the substrate that has been contacted with the first pretreatment composition, serving as a cathode, said cathode and anode being immersed in the second composition. 
     
     
         22 . (canceled) 
     
     
         23 . A magnesium or magnesium alloy substrate treated with the system of  claim 1 , wherein (a) at least 500 counts of a lanthanide series metal is present as measured by X-ray fluorescence (measured using an X-Met 755, Oxford Instruments; operating parameters 60 second timed assay, 15 Kv, 45 μA, Lα line, T(p)=1.1 μs); (b) at least 150 counts of aluminum as measured by X-ray fluorescence (measured using an X-Met 755, Oxford Instruments; operating parameters 60 second timed assay, 15 Kv, 45 μA, Kα line, T(p)=1.1 μs); (c) no more than 25 atomic % of a lanthanide series metal between an air/substrate interface and 1 m below the air/substrate interface as measured by an EDX line scan collected from a surface of the substrate to the bulk of the substrate in cross-section with a 5.00 kV accelerating voltage and a 3.0 spot size; and/or (d) no more than 65 atomic % of oxygen between the air/substrate interface and 1 m below the air/substrate interface as measured by an EDX line scan collected from a surface of the substrate to the bulk of the substrate in cross-section with a 5.00 kV accelerating voltage and a 3.0 spot size. 
     
     
         24 . (canceled) 
     
     
         25 . The substrate of  claim 24 , comprising a first layer formed by the first pretreatment composition and/or a second layer formed by the second pretreatment. 
     
     
         26 - 28 . (canceled) 
     
     
         29 . The substrate of  claim 23 , wherein the substrate comprises a vehicle, a part, an article, a heat exchanger, an appliance, a personal electronic device, a multi-metal article, or combinations thereof. 
     
     
         30 . The substrate of  claim 29 , wherein the vehicle comprises an automobile or an aircraft. 
     
     
         31 . The substrate of  claim 23 , wherein the substrate comprises a three-dimensional component formed by an additive manufacturing process. 
     
     
         32 . (canceled)