Solution system for electrolytically removing titanium carbide coating and method for same

Abstract

A solution system for removing titanium carbide coatings on substrate surface by two electrolysis steps is provided. The solution system includes a first electrolyte solution for a first electrolysis step and a second electrolyte solution for a second electrolysis step. The first electrolyte solution contains 2-80 g/L soluble alkali metal hydroxide and 5-100 g/L complexant capable of complexing with titanium ions. The second electrolyte solution contains 50-300 g/L soluble alkali metal hydroxide, 5-100 g/L complexant capable of complexing with titanium ions, and 10-60 g/L alkylol amine. The method for removing titanium carbide coating from the substrate mainly includes two electrolysis steps respectively using the first and second electrolyte solution.

1 . An aqueous solution for electrolytically removing titanium carbide coatings from substrates, comprising:
 50-300 g/L soluble alkali metal hydroxide;   5-100 g/L complexant capable of complexing with titanium ions; and   10-60 g/L alkylol amine.   
     
     
         2 . The aqueous solution as claimed in  claim 1 , wherein the soluble alkali metal hydroxide is sodium hydroxide or potassium hydroxide, or a combination of the hydroxide and potassium hydroxide. 
     
     
         3 . The aqueous solution as claimed in  claim 2 , wherein the concentration of the soluble alkali metal hydroxide is about 120-180 g/L. 
     
     
         4 . The aqueous solution as claimed in  claim 1 , wherein the complexant is selected from one or more of the group consisting of sodium potassium tartrate, sodium gluconate, sodium citrate, ethylenediamine tetraacetic acid. 
     
     
         5 . The aqueous solution as claimed in  claim 1 , wherein the concentration of the complexant is about 5-40 g/L. 
     
     
         6 . The aqueous solution as claimed in  claim 1 , wherein the alkylol amine is selected from one or more of the group consisting of ethanolamine, diethanolamine, and triethanolamine 
     
     
         7 . The aqueous solution as claimed in  claim 1 , wherein the concentration of alkylol amine is about 18-40 g/L. 
     
     
         8 . A solution system for removing titanium carbide coatings on substrate surface by two electrolysis steps, comprising:
 a first electrolyte solution for a first electrolysis step, the first electrolyte solution containing 2-80 g/L soluble alkali metal hydroxide and 5-100 g/L complexant capable of complexing with titanium ions;   a second electrolyte solution a second electrolysis step, the second electrolyte solution containing 50-300 g/L soluble alkali metal hydroxide, 5-100 g/L complexant capable of complexing with titanium ions, and 10-60 g/L alkylol amine.   
     
     
         9 . The solution system as claimed in  claim 8 , wherein the soluble alkali metal hydroxide in the first and second electrolyte solution is sodium hydroxide or potassium hydroxide, or a combination of the hydroxide and potassium hydroxide. 
     
     
         10 . The solution system as claimed in  claim 9 , wherein the concentration of the soluble alkali metal hydroxide in the first electrolyte solution is about 5-50 g/L; the concentration of the soluble alkali metal hydroxide in the second electrolyte solution is about 120-180 g/L. 
     
     
         11 . The solution system as claimed in  claim 8 , wherein the complexant in the first and second electrolyte solution is selected from one or more of the group consisting of sodium potassium tartrate, sodium gluconate, sodium citrate, ethylenediamine tetraacetic acid. 
     
     
         12 . The solution system as claimed in  claim 11 , wherein the concentration of the complexant in the first and second electrolyte solution is about 5-40 g/L. 
     
     
         13 . The solution system as claimed in  claim 8 , wherein the alkylol amine is selected from one or more of the group consisting of ethanolamine, diethanolamine, and triethanolamine. 
     
     
         14 . The solution system as claimed in  claim 13 , wherein the concentration of the alkylol amine is about 18-40 g/L. 
     
     
         15 . A method for removing a titanium carbide coating from a substrate, comprising:
 partially removing the titanium carbide coating by a first electrolysis step in a first electrolyte solution using the substrate as the anode, the first electrolyte solution containing containing 2-80 g/L soluble alkali metal hydroxide and 5-100 g/L complexant capable of complexing with titanium ions; and   completely removing the remainder titanium carbide coating by a second electrolysis step in a second electrolyte solution using the substrate combined with the coating as the anode, the second electrolyte solution containing 50-300 g/L soluble alkali metal hydroxide, 5-100 g/L complexant capable of complexing with titanium ions, and 10-60 g/L alkylol amine.   
     
     
         16 . The method as claimed in  claim 15 , wherein the anodic current density in the first electrolysis step and second electrolysis step is about 1-10A/dm 2 ; the first electrolysis step and second electrolysis step each takes about 3-8 minutes. 
     
     
         17 . The method as claimed in  claim 16 , wherein the first electrolysis step and second electrolysis step each continues for about 4-7A/dm 2 . 
     
     
         18 . The method as claimed in  claim 15 , wherein the temperature of the first electrolyte solution during the first electrolysis step is maintained between about 50° C. and about 95° C.; the temperature of the second electrolyte solution during the second electrolysis step is maintained between about 50° C. and about 95° C. 
     
     
         19 . The method as claimed in  claim 18 , wherein the temperature of the first electrolyte solution during the first electrolysis step is maintained between about 60° C. and about 80° C.; the temperature of the second electrolyte solution during the second electrolysis step is maintained between about 60° C. and about 80° C. 
     
     
         20 . The method as claimed in  claim 15 , wherein the substrate is ferric-based alloy.