Novel insights into the synthesis and tribo-mechanical performance of high-entropy (Hf0.2Zr0.2Ti0.2W0.2Mo0.2)B2 ceramics

Abstract

High-entropy (Hf_0.2Zr_0.2Ti_0.2W_0.2Mo_0.2)B₂ ceramics were synthesized using a two-step spark plasma sintering process, with densification at 1600 °C followed by sintering at 1850 °C. This method produced dense materials with excellent mechanical and tribological properties. Hardness values ranged from 18.85 GPa to 39.65 GPa, with a maximum Young’s modulus of 319 GPa. Micro-scratch tests showed high resistance to plastic deformation and minimal surface damage, highlighting durability under mechanical stress. Tribological tests at 15 N and 20 N loads demonstrated exceptional wear resistance, attributed to hard primary phases and lubricating soft secondary phases. These findings confirm the material’s robustness and show the effectiveness of the two-step synthesis in optimizing microstructure and enhancing properties, making it suitable for high-stress and wear-intensive applications.