Effect of carbon quantum dots on the corrosion and wear resistance of WC-Co cemented carbide

Cemented carbide is widely used in cutting, mining, and aerospace industries due to its exceptional hardness and wear resistance; however, its effectiveness in corrosive or high-friction environments is constrained by its limited fracture toughness and insufficient corrosion resistance. In this study, nitrogen-doped carbon quantum dots (N-CQDs) were incorporated to strengthen WC-10Co cemented carbide synthesized through the powder metallurgy route, followed by a comprehensive investigation of their structural, mechanical, electrochemical, and tribological properties. Results revealed that an optimal addition of N-CQDs promoted WC grain refinement and reduced porosity, resulting in enhanced interfacial bonding and structural uniformity in the sintered composites. The sample 1 wt.% N-CQDs demonstrated 7.4% increase in hardness (from 1355 to 1455 HV), a 25.7% enhancement in fracture toughness (from 12.32 to 15.49 MPa·m 1/2 ), a 38.4% decrease in corrosion current density, and a reduced wear rate from 4.73 × 10 -6 to 5.50 × 10 -6 mm 3 ·N -1 ·m -1 relative to the undoped counterpart. This sample displayed an evident increase in impedance modulus and a substantial reduction in wear rate, attributable to the formation of a compact passive film and a stable nano-lubricating layer. Lower N-CQDs additions yielded only minor enhancements, while excessive doping induced agglomeration and interfacial defects, ultimately decreasing the overall performance. These results demonstrate that optimal incorporation of N-CQDs offers a feasible and cost-effective strategy for improved durability and service life of WC-10Co cemented carbide under harsh service conditions.