Brass Corrosion under a single droplet of NaCl

A droplet of NaCl was gently placed horizontally on brass surface and corrosion rate, contact angle, volume loss and droplet height were monitored with droplet holding time. The corrosion rate of brass decreases during the initial stage of monitoring then slowly increases and eventually attains a steady state value during the last stage of monitoring. The droplet height continually dropped during the evaporation process, while the volume loss increases as the droplet holding time increases. The drop diameter remained relatively constant, while the contact angle continually decreased as droplet holding time progressed. A mechanism describing the successive stages of brass corrosion is proposed.