On the crystallite size refinement of ZrB2 by high-energy ball-milling in the presence of SiC

• Published in: Journal of the European Ceramic Society Vol. 31; no. 13; pp. 2407 - 2414
• Main Authors: Zamora, V, Ortiz, A L, Guiberteau, F, Nygren, M, Shaw, L L
• Format: Journal Article
• Language: English
• Published: 01-11-2011
• Subjects: Agglomerates; Ceramics; Communities; Crystallites; Dispersions; Milling (machining); Nanoparticles; Silicon carbide
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2011.05.035

The effect of SiC additions (5, 17.5, and 30 vol%) on the high-energy ball-milling (HEBM) behaviour of ZrB2 was investigated. The presence of SiC during HEBM did not alter the ZrB2 refinement mechanism of repeated brittle fracture followed by cold-welding, thereby leading to the formation of agglomerates consisting of primary nanoparticles. SiC did, however, slow down the kinetics of crystallite size refinement and promoted the formation of finer agglomerates. Both of these phenomena became more pronounced with increasing SiC content in the ZrB2 + SiC powder mixtures, and they were attributed to the energy dissipation effect of the nanocrystalline SiC particles during HEBM of the ZrB2 + SiC powder mixture. This study offers evidence that the addition of harder materials to softer materials can slow down the refinement of crystallite sizes, and thus provides a new mechanism to control crystallite sizes during HEBM. The simultaneous attainment of nanoparticles of ZrB2 and SiC, reduced agglomerate sizes, and homogeneous SiC dispersion at the nanometre scale may have important implications for the ultrahigh-temperature ceramic community, as it simplifies the processing route and is likely to facilitate the sintering of ZrB2-SiC composites.