Effect of WC Particle Addition on the Wear Resistance of FeCoNiAlTi Coatings

X70 pipeline steel is frequently employed in oil and gas pipelines, which demands commendable wear resistance throughout the transportation process. In this study, a series of FeCoNiAlTi high-entropy alloy (HEA) coatings reinforced with tungsten carbide (WC) particles were synthesized on X70 through laser cladding. The impact of WC on the microstructure, hardness, and tribological behavior of the coatings was comprehensively explored. Microstructural analysis using scanning electron microscopy, thermodynamic prediction, and x-ray diffraction elucidates the composition and phase distribution of the coatings. Hardness assessments were conducted using hardness testers, whereas frictional properties were evaluated using multipurpose friction and wear test rigs along with white-light interferometers. The HEA coating predominantly consisted of face-centered cubic and body-centered cubic phases, showing augmented hardness and wear resistance attributed to solid-solution and fine crystallization effects. The incorporation of WC contributed to the increased presence of hard carbides within the coating, which further intensified its hardness. Notably, the 40wt.% WC coating exhibited a peak average hardness of 859.65 HV_1.0. Analysis of the frictional properties revealed a nuanced relationship between the hardness and friction characteristics. Surprisingly, the 20wt.% WC coating exhibited superior wear resistance, with the lowest wear rate recorded at 7.38 × 10⁻⁷ mm³/Nm. This underscores the intricate interplay of factors influencing the tribological behavior of the coatings, indicating that a higher hardness does not necessarily translate to improved frictional performance. These findings provide valuable insights into optimizing the composition of HEA coatings for enhanced wear resistance in X70 pipeline steel applications.