Method and apparatus for removing electrically conductive coatings on metallic surfaces

A method of removing a conductive coating from a metallic component, the method comprising:

• providing a tank containing an aqueous solution of ammonium citrate, sodium dihydrogen citrate, and potassium citrate, the aqueous solution acting as liquid electrolyte, and a cathode made of 316 SS immersed in the liquid electrolyte;
• immersing the metallic component containing more than one electrically conductive coating into the liquid electrolyte to act as an anode;
• providing a DC power supply capable of producing at least 150 volts connected to the anode and cathode to form an electrolytic cell capable of producing a plasma on the metallic component containing more than one electrically conductive coating;
• and
• activating the DC power supply to produce a plasma on the metallic component containing more than one electrically conductive coating for a time period in the range of 3-8 minutes such that one of the more than one conductive coating on the metallic component partially or fully disintegrates into particles wherein the particles i) fully dissolve in the liquid electrolyte, or ii) partially dissolve in the liquid electrolyte or iii) are suspended in the liquid electrolyte or iv) settle to bottom of the tank containing the liquid electrolyte, or v) contain particles suspended in the electrolyte and particles settled in bottom of the tank containing the liquid electrolyte, in response to values selected for voltage and current of the DC power supply, pH of the liquid electrolyte, and material of the cathode.

An apparatus for removing an electrically conductive coating from a metallic component comprising:

• a tank containing a liquid electrolyte;
• a cathode immersed in the liquid electrolyte;
• the metallic component coated with more than one electrically conductive coating acting as an anode immersed in the liquid electrolyte;
• and
• a DC power supply connected to the anode and cathode to form an electrolytic cell, the electrolytic cell being capable of producing a plasma on the coated metallic component, such that the one of the more than one electrically conductive coating from the metallic component disintegrates into particles falling into the liquid electrolyte, in response to values selected for voltage and current of the DC power supply, and pH of the liquid electrolyte, and material of the cathode.