Experimental Investigation on the Corrosivity of Atmosphere through the Atmospheric Corrosion Monitoring (ACM) Sensors

摘要

Atmospheric corrosion is a destructive attack of metallic material by chemical or electrochemical reaction between the metal and its environment. To investigate the corrosivity of atmosphere, in this research, several chemical species like NaCl, KCl, Na_2SO_4, NaNO_3, KNO_3, MgCl_2.6H_2O, and Mg(NO_3)_2.6H_2O, were used as artificial rainfall solution with the variation of concentrations. Four types of ACM sensors which consist of Fe-Ag, Zn-Ag, Al-Ag, and Cu-Ag galvanic couples were used to define the correlation between sensor output and Corrosion Rate (CR) which affected by the chemical concentration of individual and mixed solutions. The results reveal that the corrosivity of the cation is negligible compared to the anion. In term of the concentration, the (SO_4)~(2-) anion is more corrosive than Cl~- and (NO_3)~- anion respectively. The signal output of ACM sensors give a good relation for determining the CRs in both individual and mixed solutions, and it can be used to forecast some chemical species in Atmosphere. And also the time of wetness, the time which makes corrosion possible, could be predicted.