Erosive wear characteristics and damage model of polycrystalline diamond compact for enhancing mud pulser rotor

Abstract

The rotor of the mud pulser will suffer severe erosive wear due to long-term scouring by solid particles in drilling mud. An important way to solve this problem is to improve the erosion resistance of the rotor. Polycrystalline diamond compact (PDC) has excellent mechanical properties. To explore the erosive wear characteristics of the PDC for enhancing mud pulser rotor, the influence of the impact angle (30°, 45°, 60°, 75°, and 90°) and diamond grain size (4 μm, 10 μm, 20 μm, and 30 μm) on the erosion rate of the PDC was investigated. The results show that the PDC erosion rate is positively correlated with the impact angle and diamond grain size. When the impact angle is 90° and the diamond grain size is 4 μm, the PDC erosion rate is the smallest, 0.81%, and when the diamond grain size is 30 μm, the PDC erosion rate is the largest, 2.12%. The erosive wear characteristics of the PDC are cobalt removal and diamond grain cutting at a low impact angle. At high-impact angles, there is a micro-fracture of the edge of the diamond grains and an intersection of transverse and radial cracks. The fine diamond in PDC is removed, and the coarse diamond in PDC seems to have a trans-granular fracture. An innovative cutting-crack damage model considering the diamond grain sizes and impact angles is proposed based on the erosion damage mechanism, which can better predict the evolving law of the PDC erosion rate. The results provide data support and theoretical guidance for the application of PDCs to enhance erosion resistance rotors.