Calculate the corrosion current density (in mA/cm²) of a silver electrode in a galvanic couple with a standard hydrogen electrode if the measured potential of the silver electrode is -0.25 V versus the standard hydrogen electrode at a temperature of 25 °C. The Tafel slope of the silver electrode is 30 mV/decade and the corrosion potential of silver in the given environment is -0.15 V.

Question

Calculate the corrosion current density (in mA/cm²) of a silver electrode in a galvanic couple with a standard hydrogen electrode if the measured potential of the silver electrode is -0.25 V versus the standard hydrogen electrode at a temperature of 25 °C. The Tafel slope of the silver electrode is 30 mV/deca

Answer 1

To calculate the corrosion current density, we can use the Tafel equation:E = E_corr +  b * log10 i / i_corr  Where:E = measured potential  -0.25 V E_corr = corrosion potential  -0.15 V b = Tafel slope  30 mV/decade i = current density  mA/cm i_corr = corrosion current density  mA/cm First, we need to rearrange the equation to solve for i_corr:i_corr = i * 10^ E - E_corr  / b Now, we can plug in the given values:i_corr = i * 10^ -0.25 -  -0.15   / 0.03 Since we don't have the value of i  current density , we cannot directly calculate the corrosion current density  i_corr . However, if we had the value of i, we could plug it into the equation above to find i_corr.