Densification, mechanical, and tribological properties of ZrB2‐ZrCx composites produced by reactive hot pressing

ZrB2‐ZrCx composites were produced using Zr:B4C powder mixtures in the molar ratios of 3:1, 3.5:1, 4:1, and 5:1 by reactive hot pressing (RHP) at 4‐7 MPa, 1200°C for 60 minutes. X‐ray diffraction analyses confirmed the formation of nonstoichiometric zirconium carbide (ZrCx) with different lattice parameters and enhanced carbide formation by increasing the Zr mole fraction. An increase in applied pressure from 4 to 7 MPa was responsible for the improved relative density (RD) of 4Zr:B4C composition from 86% to 99%. Microstructural studies on Zr‐rich composites showed a reduction in unreacted B4C particles and enriched elongated ZrB2 platelets. Reaction and densification mechanism in 4Zr:B4C composition were studied as a function of temperature increased from 600 to 1200°C at an applied constant pressure of 7 MPa. After 1000°C,