can you give more data on what is the potential range and what is the solution in which is used for polarization and also what is the substrate and coating thickness of Cu
In polarization curves of sol-gel coated cu electrodes in 3.5 % NaCl, the current rises continuously with increase in potential. What does it mean? Why?
When you apply potential current rises due to electrochemical reaction till O xygen evolves or on cathodic side Hydrogen evolves? it is simple E vs I relationship --
E=f( I,t) --
sweep rate ( voltage/ sec) is a function of current --
Thanks. In the above case the polarization studies were carried between -0.6 V to +0.2 V (SCE). Above +0.2 V also the current increases continuously. Whether it implies that the coating is not that much protective towards corrosion?
if you look at the water stability areas .. like Prof. Muralidharan has mentioned.. the stability region is between -0.5 to 1 V, at neutral pH, if you have an acidic or basic solution then these limits shift..
it is clear that above 2 V what you see is current increase due to gas evolution..
also if your coating is not dense then you may find some contribution in the current from Cu dissolution.