The fundamental processes and the causes governing the corrosion behaviors of aluminum heat exchanger tubes (HETs) used in NH_3 condensing application were investigated. Experimental techniques were conducted to observe the corrosive structures of HETs, to identify the chemical compositions of corrosion products, to verify the chemical compositions of HETs, and to evaluate the corrosivity of refrigerant. Potentiodynamic polarization tests were conducted to evaluate the validity of the inhibitor added in the refrigerant. The corrosion of the HETs was found to be attributable to a deposition of rust, originating from the carbon steel shell and bottom of the condenser, which led to an occurrence of crevice corrosion or so-called deposition corrosion enhanced by the presence of chloride ion (Cl~-) in the refrigerant.
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