Low temperature synthesis of dense and ultrafine grained zirconium diboride compacts by reactive spark plasma sintering

Dense (>98%) submicron sized monolithic zirconium diboride (ZrB2) was fabricated by reactive spark plasma sintering (RSPS) of 8 h ball milled Zr and B elemental mixtures at 1200 degrees C. During RSPS, ZrB2 formed in-situ and the densification takes place by a two-step process. Plastic flow of ZrB2 resulting from application of higher pressure enhanced densification significantly. Improvement in nanohardness, elastic modulus and indentation fracture toughness were observed with increased sintering pressure. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.