The study investigates the structure of composite materials fabricated based on WC–Co alloys with varying contents of zirconium dioxide and chromium diboride using spark plasma sintering. The work examines the combined effect of ZrO2 and CrB2 additions on the performance characteristics of WC–Co composites, including the friction coefficient and wear rate during reciprocating dry sliding tests against an Al2O3 counterbody (ball) at room temperature under a load of 100 N. The sintered composites 94WC–6Co (sample 1), 89.3WC–5.76Co–4ZrO2–1CrB2 (sample 2), 86.48WC–5.52Co–6ZrO2–2CrB2 (sample 3), 82.72WC–5.28Co–8ZrO2–4CrB2 (sample 4), and 78.96WC–5.04Co–10ZrO2–6CrB2 (sample 5) exhibit well-formed isomorphic WC crystals with distinct faceting and sharp edges. The microstructure is polydisperse and combines large prismatic WC grains up to 10–15 µm with a finer fraction that fills the intergranular space. After tribological testing, the friction coefficient μ in the sample–counterbody contact for sample 1 ranged from 0.75 to 0.85. For samples 2, 3, 4, and 5, μ ranged from 0.3–0.41, 0.5–0.6, 0.7–0.8, and 0.82–0.95, respectively. The wear rate for samples 2, 3, and 4 are (2.143 ± 0.532) × 10–7, (3.216 ± 0.758) × 10–7, and (6.784 ± 0.852) × 10–7 mm3/(N m), respectively, which is 3.7, 2.5, and 1.2 times lower than that of sample 1, placing them among highly wear-resistant materials. Composites containing ZrO2 and CrB2 additions (samples 2, 3, and 4) demonstrate superior tribological performance compared with sample 1 because they exhibit greater resistance to abrasive and adhesive wear. The additions promote the formation of a finer-grained structure with a uniform distribution of WC grains and dispersion strengthening at the interfaces between WC grains and the cobalt binder phase Co. However, increasing the content of ZrO2 and CrB2 to 10 and 6%, respectively, in the composition leads to a 1.3-fold decrease in wear resistance. From the standpoint of service performance, sample 2, which contains 4ZrO2 and 1CrB2, represents the optimal composition. During reciprocating sliding against an Al2O3 ball, abrasive wear dominates in sample 1. Adhesive wear, which results from the embedding of wear debris into the friction surface, affects the wear rate to a lesser extent than abrasive wear. The introduction of ZrO2 and CrB2 into the 94WC–6Co composite decreases the contribution of abrasive wear and increases the contribution of adhesive wear.
Meсhnik et al. (Wed,) studied this question.