Influence of Temperature and Relative Humidity on the Atmospheric Corrosion of Zinc in Field Exposures and Laboratory Environments by Atmospheric Corrosion Monitor

In the present work, the effect of temperature and relative humidity on the corrosion rate of zinc in field exposures for nearly one year or in laboratory corrosion environments was investigated by zinc- graphite coupling type atmospheric corrosion monitor (ACM) sensor. During the field exposure, the temperature, relative humidity and corrosion rate were monitored continuously at the same time. The results showed that using the time of wetness (TOW) alone to estimate the corrosion rate of zinc had some limitations. To address this problem, ACM was also used in laboratory corrosion tests, which were performed in the chamber with controlled temperature and humidity. It was found that both temperature and relative humidity could affect the corrosion rate of zinc, and there was a coupling effect between the temperature and relative humidity on the corrosion rate. Based on the data from the laboratory corrosion tests, a new equation was proposed to describe the correlation of corrosion rate with temperature and relative humidity, which also considered the coupling effect between temperature and relative humidity. This equation better reflected the atmospheric corrosion rate of Zn during field exposures compared to the TOW.