Definition - What does Cathodic Cleaning mean?
Cathodic cleaning is a procedure to remove buildup or corrosion formations from a metallic surface by wiring it as an electrode to an electric current in an electrolytic cell. It is a type of electroplating activity that is effective and causes minimal surface interference.
This precision cleaning method is usually performed as a final cleaning step before electroplating and after pre-cleaning with solvents or alkaline baths.
Corrosionpedia explains Cathodic Cleaning
Prior cleaning with solvents and alkaline baths is vital for cathodic cleaning.
Cathodic cleaning involves the release of hydrogen at the cathode. Two hydrogen moles and one oxygen mole is released during electrolysis of water (H2O). The metal surface to be cleaned is made the cathode to induce a reduction reaction. The reactionary exchange is:
4H+ + 4e- = 2H2(g)
and is properly supported with an acidic environment to provide an adequate supply of hydrogen ions for the forward reaction, which enables the removal of rust and other undesired oxides from the metal's surface.
The increased presence of hydrogen makes any metal undergoing cathodic cleaning more prone to hydrogen embrittlement.