Development of Accelerated Galvanic Corrosion Testing for Evaluating Heat Exchanger Corrosion Penetration Lifespan

A new lifespan evaluation method, accelerated galvanic corrosion testing (AGCT), was developed for evaluating the lifespan of aluminum heat exchangers during the materials development stage. AGCT effectively accelerated corrosion by adjusting the polarization magnitude, which aligns with the polarization direction of sacrificial anode cathodic protection (SACP). Increasing the zinc content in the fin alloy (1.8 wt%, 2.2 wt%, 2.6 wt%, and 3.0 wt%) enhanced the SACP effect, with a 3.0 wt% Zn resulting in a 49% increase in the penetration lifespan of the heat exchanger. Galvanic simulation has confirmed that protection of the tube and filler is provided at zinc contents of 2.2 wt% or higher, but there is evidence of overprotection at 3.0 wt% Zn. Therefore, the optimal zinc content of fin was determined to be 2.6 wt%, which is expected to improve the heat exchanger penetration lifespan by up to 43%.