Field assisted sintering of graphene reinforced zirconia ceramics

摘要

Three mol. % yttria stabilized zirconia (3Y-TZP) with Graphene platelets (GNPs) powder mixture was produced by ball milling using dimethyl formamide (DMF) as dispersion media. The GNPs-reinforced 3Y-TZP composites were densified (similar to 99%) by field assisted sintering technology (FAST). A homogeneous dispersion of GNPs in 3Y-TZP is observed from the sintered samples, and the GNPs are bent and embedded between the grains, which results in increasing the contact area. The trans-granular mechanism of crack propagation becomes increasingly dominant by adding GNPs. The fracture toughness reaches 15.3 MPa . m(1/2), as tested by single-edge notched beam method, which reflects an increase of 61% compared to GNPs-free 3Y-TZP. On the other hand, with higher GNPs content, the improvement in fracture toughness is limited. Toughening mechanisms, as determined through micro-hardness testing, including pull out, crack deflection, crack bridging, and micro-cracks, are observed and discussed. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.