Method of making aluminum-coated metal

Abstract

A method of coating a metal substrate is disclosed in which the metal substrate is disposed as an anode in an electrolytic circuit with an aqueous alkaline liquid electrolyte. An electrical voltage differential is applied to the metal substrate and a cathode. The treated metal substrate is disposed as a cathode in an electrolytic circuit with an ionic liquid electrolyte and an aluminum salt. An electrical voltage differential is applied to the metal substrate and an anode to form an aluminum layer on the metal substrate.

1 . A method of coating a metal substrate, comprising
 disposing the metal substrate as an anode in an electrolytic circuit comprising an aqueous alkaline liquid electrolyte, and applying an electrical voltage differential to the metal substrate and a cathode; and   disposing the metal substrate as a cathode in an electrolytic circuit comprising a liquid electrolyte that comprises an ionic liquid and an aluminum salt, and applying an electrical voltage differential to the metal substrate and an anode to form a layer comprising aluminum on the metal substrate.   
     
     
         2 . The method of  claim 1 , further comprising degreasing the metal substrate prior to disposing in the aqueous alkaline liquid electrolyte. 
     
     
         3 . The method of  claim 1 , further comprising grit blasting the metal substrate prior to disposing in the aqueous alkaline liquid electrolyte. 
     
     
         4 . The method of  claim 1 , further comprising degreasing and grit blasting the metal substrate prior to disposing in the aqueous alkaline liquid electrolyte. 
     
     
         5 . The method of  claim 1 , further comprising subjecting the metal substrate to ultrasonic cleaning prior to forming the layer comprising aluminum on the metal substrate. 
     
     
         6 . The method of  claim 1 , wherein the formation of the layer comprising aluminum on the metal substrate is performed under conditions to produce the layer comprising aluminum, at a volumetric density greater than 99%. 
     
     
         7 . The method of  claim 1 , wherein the metal substrate comprises steel. 
     
     
         8 . The method of  claim 1 , wherein the electrolytic circuit comprising a liquid electrolyte that comprises an ionic liquid and an aluminum salt includes an aluminum anode. 
     
     
         9 . The method of  claim 1 , further comprising, prior to forming the layer comprising aluminum on the metal substrate, disposing the metal substrate as an anode in an electrolytic circuit comprising a liquid electrolyte that comprises an ionic liquid, and applying an electrical voltage differential to the metal substrate and a cathode. 
     
     
         10 . The method of  claim 9 , further comprising degreasing and grit blasting the metal substrate prior to disposing in the aqueous alkaline liquid electrolyte. 
     
     
         11 . The method of  claim 9 , further comprising subjecting the metal substrate to ultrasonic cleaning prior to forming the layer comprising aluminum over the metal substrate. 
     
     
         12 . The method of  claim 9 , wherein the formation of the layer comprising aluminum on the metal substrate is performed under conditions to produce the layer comprising aluminum, at a volumetric density greater than 99%. 
     
     
         13 . The method of  claim 9 , wherein the metal substrate comprises steel. 
     
     
         14 . The method of  claim 9 , wherein the electrolytic circuit comprising a liquid electrolyte that comprises an ionic liquid and an aluminum salt includes an aluminum anode. 
     
     
         15 . An article, comprising:
 a metal substrate; and   a layer comprising aluminum over the metal substrate, at a volumetric density greater than 99%, wherein said article meets or exceeds requirements hydrogen embrittlement test requirements of ASTM F519-10.   
     
     
         16 . The article of  claim 15 , wherein the metal substrate comprises steel. 
     
     
         17 . The article of  claim 16 , wherein the metal substrate comprises high strength low alloy steel.