| By using the rotating disc electrode and the constant temperature water control device to simulate the seawater cooling system working condition, a new test system for brass tube corrosion monitor is built up. The HAl77-2 brass tube has been test in the system. The results make clear how flow rate, temperature and inhibitor affect its corrosion behavior. The main achievements are list as follows:EIS and linear polarization methods were used. The results show that the EIS of HAl77-2 brass alloy in seawater at different flow velocities presents different characteristics:The EIS presents characteristics of diffusion control in still water; The EIS characteristics is charge transfer control when the flow velocity is lower than 4m/s; Inductive reactance arc occurs when the flow velocity is higher than 4.5m/s. The corrosion rate of HAl77-2 brass is influenced by the flow velocity: The corrosion rate increase linearly when the flow velocity is lower than 2m/s; As the flow velocity increase from 2m/s to 4m/s, the corrosion rate increase insignificantly. Pitting occurs when the flow velocity is higher than 4.5m/s, consequently the corrosion rate increase sharply.The constant current step method and EIS is used to study how temperature affects the corrosion behavior of HAl77-2 brass tube. The results show that the corrosion rate is increasing as temperature getting higher when temperature is below 50℃. When temperature is rising from 50℃, the oxygen concentration falls to a limited value, in contrary, the corrosion rate is decline.A new inhibitor is tested. The results show its performance is excellent. It is a combine type inhibitor. It can form a protecting film in the HAl77-2 brass surface, which can decline the corrosion rate. When the flowing rate reaches 5m/s, the protecting film still keep integrity, thereby pitting can be avoid.
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