Titanium Anode

In this equation, Y0 is a constant which is independent of the frequency (fixed phase constant), ω is the angular frequency, and n is the power factor related to the local torsion angle. According to Fig. 7, the charge transfer resistance at the external active surface of oxide coating with 70% IrO2-30% ZrO2 composition at 1.15 V is very high and equals 2841 Ω cm2.

The Tafel diagram for Titanium Anode with IrO2-30% ZrO2 70% coating at 1.15 volts showed its current density is much lower than that of other compounds, and it is nearly located in the passive region in this potential. Therefore, for this coating it is expected to have a high charge transfer resistance. However, in potentials of 1.35 and 1.50 volts, the charge transfer resistance

With increasing Rhodium molar percentage, the amorphous phase increases in the oxide coating, so it is expected that the capacitance of the three-component coatings is much higher than that of the coatings without Rhodium. At 1.51 V, the two-component coating exhibits a higher capacitance than the triple coatings. This is due to the fact that, in higher over voltages, the released gases will fill the coating’s groove regions and reduce the active surface area of the coating. Therefore, the ability to perform electrochemical reactions will be greatly reduced in high over voltages by increasing the rhodium content. This leads to creation of more cracks in triple coatings and filling of these cracks by released gases which reduces the ability of coatings to perform electrochemical reactions. Conversely, in double component coatings, the capacitance of the double layer at the interface between the outer surface and the electrolyte increases. It can be argued that by increasing the release rate of oxygen gas and O2 molecule attacks on the surface of the coating and creation of the teeth like morphology, and naturally increasing the active surface area, the capacitance of the double layer at the interface between the outer surface with the electrolyte for the Ti / 70% IrO2-30% ZrO2 electrode increases. Rhodium-containing coatings have a higher roughness but, in the case of high over-voltage conditions, released gas will fill the cracks temporarily. Also, the outer pores of the coating become eroded due to the collision of the produced bubbles and the surface roughness decreases. Therefore, these two factors reduce the amount of Cdl, O. Although the high current density is released from the sample during the EIS test, it is thought that only an average of the exterior surface of the sample acts as an active electrochemical site. In fact, the