Vacuum impregnation of anodic oxidation coating (aoc) treated surfaces on valve metal substrates

Abstract

A corrosion-resistant workpiece is provided. The corrosion-resistant workpiece includes a matrix including a valve metal or an alloy including a valve metal; an oxide layer formed on the matrix, the oxide layer including a plurality of pores, wherein each pore of the plurality has a pore volume; and a polymeric composition disposed within at least a portion of the plurality of pores, wherein greater than or equal to about 70% of the pore volume for each pore having the polymeric composition disposed therein is filled with the polymeric composition. A method of fabricating the corrosion-resistant workpiece is also provided.

What is claimed is: 
     
         1 . A corrosion-resistant workpiece comprising:
 a matrix comprising a valve metal or an alloy comprising a valve metal;   an oxide layer formed on the matrix, the oxide layer comprising a plurality of pores, wherein each pore of the plurality has a pore volume; and   a polymeric composition disposed within at least a portion of the plurality of pores, wherein greater than or equal to about 70% of the pore volume for each pore having the polymeric composition disposed therein is filled with the polymeric composition.   
     
     
         2 . The corrosion-resistant workpiece according to  claim 1 , wherein the valve metal is selected from the group consisting of magnesium, aluminum, titanium, zirconium, hafnium, chromium, cobalt, molybdenum, vanadium, tantalum, mixtures thereof, and alloys thereof. 
     
     
         3 . The corrosion-resistant workpiece according to  claim 1 , wherein the oxide layer is formed on the matrix by micro-arc oxidation. 
     
     
         4 . The corrosion-resistant workpiece according to  claim 1 , wherein the polymeric composition comprises a polyacrylate. 
     
     
         5 . The corrosion-resistant workpiece according to  claim 1 , wherein the polymeric composition comprises poly(acrylic acid) (PAA), poly(methacrylate) (PMA), poly(methyl methacrylate) (PMMA), poly(ethylacrylate) (PEA), poly(ethyl methacrylate) (PEMA), or combinations thereof. 
     
     
         6 . The corrosion-resistant workpiece according to  claim 1 , wherein the polymeric composition is disposed within greater than or equal to about 95% of the plurality of pores. 
     
     
         7 . The corrosion-resistant workpiece according to  claim 6 , wherein greater than or equal to about 90% of the pore volume for each pore having the polymeric composition disposed therein is filled with the polymeric composition. 
     
     
         8 . The corrosion-resistant workpiece according to  claim 1 , wherein the oxide layer is substantially free of vacant pores when no additional layer is disposed on the oxide layer. 
     
     
         9 . The corrosion-resistant workpiece according to  claim 1 , wherein the corrosion-resistant workpiece is a component of an automobile selected from the group consisting of a wheel, a pillar, a bracket, a bumper, a roof rail, a rocker rail, a rocker, a control arm, a beam, a tunnel, a step, a subframe member, a pan, a panel, or a reinforcement panel. 
     
     
         10 . A method of fabricating a corrosion-resistant workpiece, the method comprising:
 transferring a workpiece into a chamber at least partially filled with a monomer resin, the workpiece comprising a matrix comprising a valve metal or an alloy comprising a valve metal and an oxide layer formed on the matrix, the oxide layer comprising a plurality of pores, wherein each pore of the plurality has a pore volume;   applying a vacuum to the chamber and removing air from the plurality of pores;   releasing the vacuum and forcing the monomer resin to be disposed in at least a portion of the plurality of pores; and   converting the monomer resin disposed in the at least a portion of the plurality of pores into a polymeric composition and forming the corrosion-resistant workpiece,   wherein greater than or equal to about 70% of the pore volume for each pore having the polymeric composition disposed therein is filled with the polymeric composition.   
     
     
         11 . The method according to  claim 10 , wherein each pore of the plurality has a diameter at an exposed surface of the oxide layer of greater than or equal to about 0.5 μm to less than or equal to about 20 μm. 
     
     
         12 . The method according to  claim 10 , wherein the valve metal is selected from the group consisting of magnesium, aluminum, titanium, zirconium, hafnium, chromium, cobalt, molybdenum, vanadium, tantalum, mixtures thereof, and alloys thereof. 
     
     
         13 . The method according to  claim 10 , wherein the applying the vacuum comprises applying a vacuum pressure of greater than or equal to about 0.1 Torr to less than or equal to about 0.5 Torr for a time period of greater than or equal to about 1 minute to less than or equal to about 6 hours. 
     
     
         14 . The method according to  claim 10 , wherein the converting the monomer resin into a polymeric composition comprises curing the monomer resin at a temperature of greater than or equal to about ambient temperature or room temperature to less than or equal to about 100° C. for a time period of greater than or equal to about 1 minute to less than or equal to about 1 hour. 
     
     
         15 . The method according to  claim 10 , further comprising, after the converting:
 applying a primer layer to the workpiece.   
     
     
         16 . A method of fabricating a corrosion-resistant workpiece, the method comprising:
 removing air contained within a plurality of pores defined by an oxide layer having a porosity of greater than or equal to about 20% to less than or equal to about 90%, the oxide layer formed on a matrix of a workpiece, wherein the matrix comprises a valve metal or an alloy comprising a valve metal and each pore of the plurality has a pore volume;   actively forcing a monomer resin into at least a portion of the plurality of pores; and   curing the monomer resin in the at least a portion of the plurality of pores to generate the corrosion-resistant workpiece,   wherein greater than or equal to about 90% of the pore volume for each pore having the polymeric composition disposed therein is filled with the polymeric composition.   
     
     
         17 . The method according to  claim 16 , wherein the removing air contained within the plurality of pores is performed by applying a vacuum to a chamber containing the workpiece and the monomer resin and the actively forcing the monomer resin into the at least a portion of the plurality of pores is performed by releasing the vacuum. 
     
     
         18 . The method according to  claim 16 , wherein the monomer resin comprises monomers selected from the group consisting of acrylic acid, methacrylic acid, methyl methacrylic acid, ethyl acrylic acid, ethyl methacrylic acid, salts thereof, and combinations thereof. 
     
     
         19 . The method according to  claim 16 , wherein the valve metal is selected from the group consisting of magnesium, aluminum, titanium, zirconium, hafnium, chromium, cobalt, molybdenum, vanadium, tantalum, mixtures thereof, and alloys thereof. 
     
     
         20 . The method according to  claim 16 , wherein the oxide layer of the corrosion-resistant workpiece is substantially free of vacant pores.