What differences between MMO Anode and Sacrificial Anode in Cathodic Protection System

Apr 09, 2021

What Differences between MMO Anode and Sacrificial Anode in Cathodic Protection System

MMO anodes are featured for longer service life and lower consumption rate comparing with the sacrificial anode, they are mostly used in impressed current cathodic protection. While sacrificial anode is mostly used for the galvanic systems.

What are the differences between MMO anode and sacrificial anode, below list is a detailed comparison?   

No. MMO Anode for ICCP system Sacrificial Anode for Galvanic System
1 Longer design life(25+ yrs) Short design life in comparison to MMO Anode
2 Once installed only requires annual system checks. Disruptive-repeating repair cycle checks;
Replacement of anodes costly.
3 External power source required No external power source required
4 Capable of operating at significantly higher current density rates-up to 100A/m2, however, in most cases the operating levels are much lower. Galvanic anodes are typically designed to operate at much lower current density.
5 Current is controlled& variable Cannot control limited current
6 High(5-25V)& variable driving force Low (<1v)& fixed driving force
7 Works with any resistivity electrolyte Requires low resistivity electrolyte
8 Proactive Sustainable Reactive
9 MMO anodes have an extremely long service life and very low  consumption rate measured in the 1-2
 mg/Amp per year.
Zinc and magnesium anodes are typically used in galvanic systems. They have a nominal consumption rate of approximately 11.24 Kg/Amp-year for zinc anode; and 7.9Kg/amp-year for magnesium anode.