利用电化学和失重测量、形貌表征以及计算流体力学仿真研究了EH36碳钢材料在含有不同粒径沙砾3.5%NaCl溶液中的低流速冲刷腐蚀行为。仿真结果表明，2 m/s较低流速下沙砾粒径的增大(100~850 μm)仍然能够提升沙砾的冲击能量。电化学和失重测量结果表明，腐蚀是低流速下导致EH36钢在含沙盐溶液中发生材料损伤的最主要因素。同时，腐蚀也是引起严重磨损发生的前提条件。随着沙砾粒径的增大，碳钢的冲刷腐蚀形貌从典型的“沿流体迹线腐蚀”转变为点蚀，表明沙砾冲击能量的增加引起点蚀萌发，进而加剧局部腐蚀。对比纯腐蚀、纯磨损和冲刷腐蚀的实验结果发现，沙砾粒径的增大导致腐蚀与磨损的协同作用效果增强。沙砾的冲击能量、局部阳极溶解和阳极液的转移共同决定了低流速下冲刷腐蚀的发展过程。

Marine carbon steels are constantly subjected to active corrosion due to significant amounts of aggressive agents in seawater. Once sand particles are entrained in seawater, the relative movement between the seawater and marine structures could further lead to erosion-corrosion of marine carbon steels. The size of the sand particles would play an important role in the synergy of erosion and corrosion. In this work, the erosion-corrosion performances of the EH36 marine carbon steel at sand impacts of different particle sizes were studied in 3.5%NaCl solution using the EIS, gravimetric measurements, and surface morphology characterization. A computational fluid dynamics simulation is used to simulate the impact velocity and trajectory of the sand particles in the test cell. The simulation results reveal that at a relatively lower flow velocity of 2 m/s, the average impact velocity of the sand particles on the electrode surface is presented as a decreasing trend along with increasing size (100-850 μm). However, increment in the particle size could still lead to rise in the impact energy due to mass increase. The EIS and gravimetric measurement results show that at low flow rate conditions, corrosion is the main contributor to the steel degradation in the sand-containing electrolyte. Meanwhile, corrosion is the prerequisite for severe erosion in this case. The steel loss induced by erosion would rise with an increase in the particle size. The surface characterization results show that the erosion-corrosion pattern changed from the typical “flow mark” to pitting damage with increasing particle size. It suggests that the increase in the impact energy could lead to a pitting initiation, thereby accelerating localized corrosion. It was determined that the particle size increase would promote the synergy of erosion and corrosion compared to pure corrosion, pure erosion, and erosion-corrosion performances. The initiation and propagation of localized erosion-corrosion are determined by the coupled effect of local sand impacts, anodic dissolution, and flow-enhanced analyte transportation. When the diameter of the sand particle is 100 μm, the erosion-corrosion process is controlled by the analyte transportation, leading to the formation of a typical “flow mark”. When the diameter of the sand particle ranges from 430 μm to 850 μm, the synergy of the sand impact and local anodic dissolution would effectively retard the analyte transportation, resulting in the formation of stable pitting damage.