Engineered Role of SiC Particle Size on Multi‐Length‐Scale Wear Damage of Spark Plasma Sintered Zirconium Diboride

Abstract

The engineered role of coarse‐SiC (D50 ≈72 μm) and fine‐SiC (D50 ≈3 μm) particles on the wear damage of zirconium boride (ZrB2) is assessed at different length scales. Monolithic ZrB2 and 20 vol% SiC reinforced ZrB2 with SiC of two different particle sizes are consolidated via spark plasma sintering. Wear tests conducted on sintered samples for examining multi‐length scale performance include fretting (micro‐wear), micro‐scratching (meso‐wear) and ball‐on‐disk (macro‐wear), under dry and unlubricated conditions. The damage assessment and wear mechanism, characterised via scanning electron microscopy and optical profilometry, show Hertzian tensile cracking in all the samples at loads ≥5 N during micro‐scratching. Wear volume, wear rate and coefficient of friction (cof) decreased with SiC reinforcement during macro‐wear. Fine‐SiC reinforced ZrB2 (ZSF) composite showed least cracking at loads ≥5 N owing to its highest fracture toughness (4.6 MPa m1/2) as compared to coarse‐SiC reinforced composite (ZSC, 2.1 MPa m1/2) and monolithic ZrB2 (3.9 MPa m1/2). Hardness of composites increases as compared to ZrB2, and ZSF shows enhanced elastic modulus and fracture toughness. In summary, superiority of ZSF in terms of improved mechanical performance and wear resistance makes it a potential high‐end material for aerospace applications, where particles with high surface impact may cause material deformation and removal.