Galvanic Cathodic Protection Evaluation of a Steel Pipe in Iraqi Soil

Corrosion is the main problem for the embedded pipelines in different environment resistivities. The most effective method to overcome this problem is cathodic protection which represents as a control method of the pipe corrosion. For achieving longer life of the external corrosion control system and evaluating the performance of aluminum alloys which have been used as sacrificed anodes to protect the embedded carbon steel pipe in different artificial simulated resistivity of soils in Iraq of [5000 , 1000 , 600 , 50 and 25 (Ω.cm)]. Results show that (Al-10 wt% Zn) as sacrificial anode alloy has the best anode capacity compared with other anodes under these conditions (Al-5 wt% Zn), and (Al-15 wt% Zn). The selection for these alloys based on that they have high potential in many environments when coupling with steels without effect of microbial, obstacle and stray current. The polarization curves of alloys also show no passivation behavior in artificial resistivities. The corrosion rate of different anode alloys was determinated as a function of applied cathodic protection. It was found a relationship between electric potential and time which determine the optimum potential in different soil types for the three above selected electrodes (anodes)