<p>This study aims to establish a test method for simultaneously evaluating material erosion and corrosion, and rotating-material wear tests were conducted using a slurry pot. The erosion and corrosion scars of specimens were assessed from photographic images, and wear condition diagrams organized by dimensionless particle size (<i>d</i>_<i>p</i>/<i>d</i>) and Reynolds number (<i>Re</i>) were constructed. Furthermore, the flow structure and particle behaviour around each specimen were visualized via ultrasonic velocity profiling to confirm the mechanism of the ratio change between erosion and corrosion. Results showed that a vortex flow formed around the specimen near the bottom of the container, which caused erosion. The outward flow height due to the vortex varied at Reynolds numbers of 5 × 10³ ≤ <i>Re</i> ≤ 1 × 10⁴ and sand particle concentrations of 2.24 ≤ <i>C</i>_<i>v</i> ≤ 40 vol%. It decreased with increasing <i>Re</i> and increased with <i>C</i>_<i>v</i>, which was consistent with the trend in the surface wear images. The proposed wear condition diagram was supported by flow visualization, which showed that erosion- and corrosion-dominated regions could be distinguished from the amount of remaining rust.</p> Graphical abstract <p></p>