Understanding the impact of water chemistry on electrode surface during cathodic protection in industrial cooling water system

The impact of chemical composition of synthetic cooling water on sacrificial and impressed current cathodic protections for mild steel was investigated. The influence of carbonate and phosphate inhibitor on the efficiency of Zn-Al alloy anode was studied. The weight loss of anode was higher in presence of phosphate whereas the mixed potential was more negative (-1030 mV). The nature of corrosion product of Zn-Al alloy anode was analysed using Fourier-transform infrared spectroscopy, X-ray powder diffraction and scanning electron microscopy. The study also reveals that the dissolution of anode was 2.5 times higher under dynamic condition. Carbonate also influenced the dissolution of the anode. Ti-TiO2/IrO2/RuO2 was selected as the anode material for impressed current cathodic protection. This study reveals that low current is required to reach the protective potential in presence of inhibitor where current demand was higher in agitated condition.

Automated summary

The study found that phosphate increases the weight loss of the anode, while carbonate also influences the anode dissolution. Additionally, under dynamic conditions, the dissolution rate of the anode is 2.5 times higher.