Revealing the coupling of multiple corrosion behaviors in the corrosion process of titanium-steel composites in marine environment

In this study, the corrosion behavior and corrosion mechanism of titanium-steel composite plate was studied through immersion tests in simulated marine solution. The result shows that the corrosion behavior of titanium-steel composite plate is coordinated by various corrosion behaviors in the near interface area and the far interface area. The corrosion behavior of carbon steel matrix in the far interface area of titanium-steel composite plate in simulated solution is the same as that of carbon steel, because it is far from the interface and is not accelerated by galvanic effect. The corrosion reactions started with localized corrosion induced by inclusions and the diffusion of aggressive ions, and then changed from localized to uniform corrosion. The carbon steel at the interface is accelerated by galvanic effect in the early stage, and the tiny defects at the interface can also be used as the basic point of corrosion initiation. In the later stage, the corrosion at the interface reached a certain level, and the corrosion at the interface turned into the joint action of galvanic corrosion and crevice corrosion. In the whole corrosion process, corrosion is more likely to occur due to stress concentration at the interface. Under the combined action of different corrosion behaviors, the corrosion rate at the interface of titanium-steel composite plate is faster than that at the far interface area.