Study On The Electrochemical Performence Of Sacrificial Anode Interferenced By Stray Current

Electricity transmission system of airport subway causes serious stray current interference on airport oil pipelines.It results that the pipe cathodic protection system could not run properly.There are serious corrosion problems in the apron pipeline.Previous studies have focused on the corrosion of stray current on pipeline itself,but the cathodic protection system,especially the sacrificial anode was not studied.The performance of pipeline sacrificial anode may be affected by stray current,so it is necessary to study the performance of the sacrificial anode under the influence of stray current.In this paper,magnesium alloy sacrificial anode was used for experimental study.The influence of direct stray current(DC),alternating stray current(AC),chloride ioncon centration and temperature on sacrificial anode electrochemical properties was studied by open circuit potential method,electrochemical impedance spectroscopy,polarization curves and corrosion morphology observation method.The experimental results showed that the presence of DC and AC stray currents could affect the efficiency of the sacrificial anode.The specific performance is as follows:As the DC stray current interference increased from 0V to 5V,the degree of positive migration of the sacrificial anode open circuit potential increased.The effect of temperature on sacrificial anode corrosion was not great,but the low temperature of 10℃ could slow down the sacrificial anode corrosion and maintain good work efficiency.With the increase of the ambient temperature,the degree of corrosion of the sacrificial anode was deepened.As the chloride ion concentration increased from 0% to 0.3%,the degree of positive migration of the sacrificial anode open circuit potential increased.The higher the chloride ion concentration was,the greater the impact on the performance of the sacrificial anode was.As the AC stray current interference increased in the range of 0~5V the corrosion rate of the sacrificial anode was faster and faster.The effect of chloride ion concentration on sacrificial anode surface corrosion was very large.The higher the chloride ion concentration was,the more serious the sacrificial anode corrosion was.The degree of corrosion of the sacrificial anode didn’t change much during the progress of temperature change.The degree of corrosion at low temperatures was not as serious as that at high temperatures,but the degree of corrosion was not much difference.So the effect of temperature on sacrificial anode surface corrosion was not great.