Abstract

''':This study investigates the anti-erosion mechanisms of a novel graphene-modified tungsten carbide coating under high-speed solid-liquid two-phase flow conditions. A liquid-solid two-phase flow erosion simulation device was employed, and fluid dynamics simulations were conducted using FLUENT software to determine the maximum experimental flow velocity. The influence of flow velocity, sand particle diameter, sand concentration, and fluid temperature on the erosion rate of the coating was systematically analyzed using the control variable method. Experimental results reveal that the erosion rate follows a power-law exponential relationship with flow velocity. When the sand particle diameter is below 0.5 mm, the erosion rate remains relatively stable; however, when the diameter exceeds 0.5 mm, the erosion rate increases significantly with particle size. Furthermore, the erosion rate exhibits a slight increase with higher sand concentrations, while a notable rise in fluid temperature leads to a substantial increase in the erosion rate, with the difference in erosion rates between the 150°C and 200°C coatings becoming more pronounced at elevated temperatures. Scanning electron microscopy (SEM) and numerical simulations were utilized to further elucidate the anti-erosion mechanisms of the coating. The incorporation of tungsten carbide significantly enhances the coating's hardness, while the addition of graphene results in a denser microstructure, effectively reducing porosity and improving the coating's resistance to impact and erosion. The findings demonstrate that the novel graphene-modified tungsten carbide coating exhibits superior erosion resistance, making it highly suitable for enhancing the durability and performance of rigid PDC drill bits in complex downhole environments.