Performance enhancement of cement matrix with B 4 C,SiC,and hBN additives under thermal shock,mechanical stress,and wear conditions

Abstract

This study investigates the effects of B₄C, hBN, and SiC reinforcements on the mechanical, thermal, and tribological properties of calcium aluminate cement (CAC)-based composites. All composite samples were prepared by incorporating each reinforcement separately at varying weight fractions, followed by systematic evaluation of compressive strength, flexural strength, thermal shock resistance, and wear behaviour. The compressive strength of B₄C-reinforced composites reached 339.1 ± 17.2 MPa, representing a 1208% increase compared to unreinforced CAC (25.93 ± 2.5 MPa). Flexural strength improved by 923%, and the residual compressive strength after thermal shock cycles reached 123.3 ± 9.3 MPa. For hBN-reinforced samples, compressive and flexural strengths increased by 804% and 213%, reaching 234.3 ± 12.1 MPa and 22.17 ± 3.2 MPa, respectively, with a post-thermal shock residual compressive strength of 81.2 ± 7.1 MPa. SiC-reinforced composites exhibited an 80% increase in compressive strength (46.48 ± 3.3 MPa) and a 23.9% improvement in flexural strength (5.45 ± 1 MPa). In terms of tribological performance, B₄C-reinforced composites showed the most significant wear resistance, with a 98.3% reduction in wear rate and a 26.7% decrease in the friction coefficient. hBN and SiC reinforcements also contributed to notable reductions in wear rate by 96% and 86.6%, respectively. These findings demonstrate that the type and content of ceramic reinforcement significantly influence the performance of CAC-based composites. Among the tested reinforcements, B₄C provided the highest overall improvements across mechanical, thermal, and tribological properties.