Metal components with inert vapor phase coating on internal surfaces

Abstract

The invention provides metal liquid chromatography components with uniformly coated internal surfaces and methods for achieving the same. The invention addresses the problem of corrosion or interference of metal components in the flow path for LC analyses in which the sample interacts with metal ions or surfaces. The invention also alleviates the difficulties in coating very long metal tubes and very small metal channels with an inert, continuous coating that adheres well to metal surfaces. The metal flow path is rendered inert by the coating, and thus compatible with bioanalytical separations, for example, by using a vapor phase deposition process to coat the inner surfaces with a coating that continuously covers all metal surfaces in the flow path.

What is claimed is: 
     
         1 . A metallic component having a lumen, passageway or cavity having an interior surface continuously covered with a protective coating having a substantially uniform thickness, wherein the protective coating is formed via a vapor phase process comprising:
 providing one or more molecular precursors in the gas phase;   exposing an interior surface of the lumen, passageway or cavity to the one or more molecular precursors in the gas phase;   allowing the one or more molecular precursors to react, decompose or otherwise change at or near the exposed interior surface and subsequently depositing thereon; and   flushing with an inert gas thus removing unreacted one or more molecular precursors and reaction byproducts, if any.   
     
     
         2 . The metallic component of  claim 1 , wherein the vapor phase process further comprises:
 repeating one of more of the above steps as necessary to arrive at an desired film thickness and/or composition.   
     
     
         3 . The metallic component of  claim 1 , wherein the lumen, passageway or cavity is characterized by at least one dimension of less than about 10 mm and one dimension longer than about 20 mm. 
     
     
         4 . The metallic component of  claim 3 , being a chromatographic column characterized by an inner diameter of less than about 10 mm and a length greater than about 20 mm. 
     
     
         5 . The metallic component of  claim 4 , wherein the protective coating has a substantially uniform thickness of about 10 nm to about 5 μm. 
     
     
         6 . The metallic component of  claim 1 , being a microfluidic device or a component thereof having at least one interior dimension less than about 1 mm. 
     
     
         7 . The metallic component of  claim 1 , wherein the protective coating comprises a material selected from Si-based, Ti-based, Zr-based or Al-based inorganic compounds. 
     
     
         8 . The metallic component of  claim 7 , wherein the protective coating comprises a material selected from SiO 2 , SiC, Si 3 N 4 , SiO x C y  (wherein 2x+4y=4), SiO m N n , (wherein 2m+3n=4), SiC x H y  (wherein 4x+y=4), TiO 2 , ZrO 2 , Al 2 O 3  and mixtures thereof 
     
     
         9 . The metallic component of  claim 1 , wherein the protective coating comprises two or more layers each comprising a different protective material. 
     
     
         10 . The metallic component of  claim 1 , wherein the metallic component is made of stainless steel, titanium, or titanium alloy. 
     
     
         11 . A method for coating an interior surface of a metallic object having a lumen, passageway or cavity, comprising forming a continuous protective coating having a substantially uniform thickness by a vapor-phase process. 
     
     
         12 . The method of  claim 11 , wherein the vapor-phase process comprises chemical vapor deposition. 
     
     
         13 . The method of  claim 11 , wherein the vapor-phase process comprises atomic layer deposition. 
     
     
         14 . The method of  claim 11 , being a chromatographic column characterized by an inner diameter of less than about 10 and a length greater than about 20 mm. 
     
     
         15 . The method of  claim 13 , wherein the protective coating has a substantially uniform thickness of about 10 nm to about 5 μm. 
     
     
         16 . The method of  claim 11 , being a microfluidic device or a component thereof having at least one interior dimension less than about 1 mm. 
     
     
         17 . The method of  claim 11 , wherein the protective coating comprises a material selected from Si-based, Ti-based, Zr-based or Al-based inorganic compounds. 
     
     
         18 . The method of  claim 17 , wherein the protective coating comprises a material selected from SiO 2 , SiC, SiC x H y , Si 3 N 4 , TiO 2 ,ZrO 2  or Al 2 O 3  and mixtures thereof. 
     
     
         19 . The method of  claim 17 , wherein the protective coating comprises two or more layers each comprising a different protective material. 
     
     
         20 . The method of  claim 11 , wherein the metallic component is made of stainless steel, titanium, or titanium alloy.