Metal substrates including metal oxide nanoporous thin films and methods of making the same

Abstract

The present disclosure is directed to a metal-containing apparatus including a substrate member constructed of a metal that is highly resistant to pitting corrosion and wear in aggressive media. An exemplary metal-containing apparatus is a plate heat exchanger. The metal includes an oxidation layer on the surface thereof and a thin metal oxide nanoporous film on top of the oxidation layer. The nanoporous film is highly compliant and is comprised of oxygen and aluminum, titanium, silicon, zirconium and combinations thereof.

We claim: 
     
         1 . A corrosion and wear-resistant metal substrate comprising:
 at least one dry oxidization layer on a surface of the substrate, the oxidization layer having a thickness of less than about 200 nanometers; and   at least a first nanoporous film chemically bonded to the oxidization layer, wherein the first nanoporous film has a thickness of less than about 1 micrometer and a porosity ranging from 26% to 80%,   wherein the first nanoporous film comprises an oxide of aluminum, titanium, silicon, zirconium, or a combination thereof.   
     
     
         2 . The corrosion and wear-resistant metal substrate of  claim 1 , further comprising a second nanoporous film on top of the first nanoporous film, wherein the first and second nanoporous films are of the same or different composition. 
     
     
         3 . The corrosion and wear-resistant metal substrate of  claim 2 , wherein the first and second nanoporous films comprise zirconium dioxide. 
     
     
         4 . The corrosion and wear-resistant metal substrate of  claim 2 , further comprising an oxide layer between the first and second nanoporous films. 
     
     
         5 . The corrosion and wear-resistant metal substrate of  claim 2 , wherein the first nanoporous and second nanoporous films comprise different compositions selected from aluminum and zirconium oxides. 
     
     
         6 . The corrosion and wear-resistant metal substrate of  claim 2 , wherein the first nanoporous and second nanoporous films comprise different compositions selected from aluminum and silicon oxides. 
     
     
         7 . The corrosion and wear-resistant metal substrate of  claim 2 , wherein the first nanoporous and second nanoporous films comprise different compositions selected from titanium and silicon oxides. 
     
     
         8 . The corrosion and wear-resistant metal substrate of  claim 2 , further comprising at least one additional nanoporous film on top of the second nanoporous film. 
     
     
         9 . The corrosion and wear-resistant metal substrate of  claim 8 , further comprising an oxide layer between each nanoporous film. 
     
     
         10 . The corrosion and wear-resistant metal substrate of  claim 2 , wherein the first and second nanoporous films each have a thickness ranging from 0.01 micrometers to about 1.0 micrometers. 
     
     
         11 . A corrosion and wear-resistant metal substrate comprising:
 at least one dry oxidization layer on a surface of the substrate, the oxidization layer having a thickness of less than about 200 nanometers;   a first nanoporous film chemically bonded to the oxidization layer, wherein the first nanoporous film has a thickness of less than about 1 micrometer and a porosity ranging from 26% to 80%; and   a second nanoporous film on top of the first nanoporous film, wherein the first and second nanoporous films comprise zirconium dioxide.   
     
     
         12 . The corrosion and wear-resistant metal substrate of  claim 11 , further comprising an oxide layer between the first and second nanoporous zirconium dioxide films. 
     
     
         13 . The corrosion and wear-resistant metal substrate of  claim 11 , further comprising at least one additional nanoporous film on top of the second zirconium dioxide nanoporous film. 
     
     
         14 . The corrosion and wear-resistant metal substrate of  claim 11 , further comprising an oxide layer between the first and second zirconium dioxide nanoporous films. 
     
     
         15 . The corrosion and wear-resistant metal substrate of  claim 11 , wherein the first and second nanoporous films each have a thickness ranging from 0.01 micrometers to about 1.0 micrometers. 
     
     
         16 . A heat exchanger comprising:
 a corrosion and wear-resistant metal substrate, wherein the substrate comprises:
 at least one dry oxidization layer on a surface of the substrate, the oxidization layer having a thickness of less than about 200 nanometers; and 
 at least a first nanoporous film chemically bonded to the oxidization layer, wherein the first nanoporous film has a thickness of less than about 1 micrometer and a porosity ranging from 26% to 80%,
 wherein the first nanoporous film comprises an oxide of aluminum, titanium, silicon, zirconium, or a combination thereof. 
 
   
     
     
         17 . The heat exchanger of  claim 16 , wherein the metal substrate further comprises a second nanoporous film on top of the first nanoporous film, wherein the first and second nanoporous films are of the same or different composition. 
     
     
         18 . The heat exchanger of  claim 17 , wherein the first and second nanoporous films comprise zirconium dioxide. 
     
     
         19 . The heat exchanger of  claim 17 , wherein the metal substrate further comprises an oxide layer between the first and second nanoporous films. 
     
     
         20 . The heat exchanger of  claim 17 , wherein the first nanoporous and second nanoporous films comprise different compositions selected from aluminum, silicon, titanium and zirconium oxides.