Novel highly scalable carbon nanotube-strengthened ceramics by high shear compaction and spark plasma sintering

We report a new strategy, based on high shear compaction and spark plasma sintering, for the massive and low cost production of 100% dense ceramics containing carbon nanotubes. Custom forming and stacking of flexible green sheets of record-breaking dimensions can yield an unlimited range of three-dimensional structures. The strategy was successfully validated in the production of multi-walled carbon nanotube/Pyrex glass materials of tube loadings in the range of 0-1.5 wt.% while no major factors limit applicability to other types of materials. Improvements in the four elastic constants of the material, Young's modulus, shear modulus, Poisson's ratio and bulk modulus, assessed by means of a non-destructive technique based on ultrasonics, were found maximum at a tube loading of 0.5 wt.% Microstructural investigations indicating the existence of highly dissipating nanoscale-specific toughening mechanisms acting complementary to nanotube bridging and pull-out indicate a high application potential in a wide range of reinforcing and multifunctional applications. (C) 2015 Elsevier Ltd. All rights reserved.