Method for depositing an aluminum oxide coating

Abstract

A method for depositing on a metal substrate a continuous coating of aluminum oxide by induction heating-assisted pressurized, temperature-controlled chemical deposition, the method including a solvothermal synthesis procedure based on an aluminum oxide precursor dissolved in a water-co-solvent mixture heated by induction to a temperature of between 400° C. and 700° C. and a pressure of between 1 MPa and 25 MPa.

1 . A method for depositing on a metal substrate a continuous coating of aluminum oxide by means of induction heating-assisted pressurized, temperature-controlled chemical deposition, said method comprising a solvothermal synthesis step based on an aluminum oxide precursor dissolved in a water-co-solvent mixture heated by induction to a temperature of between 400° C. and 700° C. and a pressure of between 1 MPa and 25 MPa. 
     
     
         2 . The method according to  claim 1 , comprising the following steps:
 a—adding the metal substrate to be coated to an induction heating-assisted pressurized, temperature-controlled chemical deposition reactor;   b—adding the aluminum oxide precursor previously dissolved in water and the co-solvent to the reactor;   c—implementing the solvothermal synthesis based on said aluminum oxide precursor by means of induction heating at a temperature of between 400° C. and 700° C. and a pressure of between 1 MPa and 25 MPa of the aluminum oxide precursor dissolved in the water-co-solvent mixture;   d—recovering the substrate coated with a continuous coating of aluminum oxide.   
     
     
         3 . The method according to  claim 1 , wherein the metal substrate is made of titanium alloy. 
     
     
         4 . The method according to  claim 1 to 3 , wherein the co-solvent is selected from alcohols, nitrogen, carbon dioxide, argon and mixtures thereof. 
     
     
         5 . The method according to  claim 1 , which is a semi-continuous method. 
     
     
         6 . The method according to  claim 1 , wherein the aluminum oxide of the continuous coating is a metastable aluminum oxide, an alpha aluminum oxide or a mixture of these oxides. 
     
     
         7 . The method according to  claim 1 , wherein the deposition speed is of between 100 and 500 nm/min. 
     
     
         8 . The method according to  claim 2 , wherein the pressure of step c) is of between 6 MPa and 10 MPa. 
     
     
         9 . The method according to  claim 3 , wherein the metal substrate is made of an alloy based on titanium aluminide. 
     
     
         10 . The method according to  claim 4 , wherein the co-solvent is nitrogen. 
     
     
         11 . The method according to  claim 6 , wherein the aluminum oxide of the continuous coating is an alpha aluminum oxide. 
     
     
         12 . The method according to  claim 7 , wherein the deposition speed is of 300 nm/min.