High temperature mechanical spectroscopy of yttria stabilized zirconia reinforced with carbon nanotubes

Abstract

High temperature mechanical properties of zirconia reinforced with carbon-nanotubes (CNTs) are studied by mechanical spectroscopy. CNTs limit zirconia grainboundary sliding (GBS) and consequently deformation. Concurrent grain-growth and plastic deformation lead to a substantial error in the evaluation of deformation activation-enthalpy. Hence, a new calculation was developed in order to account for the effect of grain growth. The corrected enthalpy is comparable with the lattice diffusion energy of cations (Zr 4þ , Y 3þ ), which evidences that at low-stress regime, GBS is accommodated by diffusional creep.

Double-walled carbon nanotube/zirconia composites: Preparation by spark plasma sintering, electrical conductivity and mechanical properties

“…With a ceramic matrix, the main aims are to increase toughness, to improve the tribological properties or to control the electrical or thermal conductivities [3][4][5]. Although most studies have been related to CNT/alumina composites, some authors used yttria-stabilized zirconia (YSZ) as the matrix, in which they add either multi-walled CNTs (MWCNTs) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] or single-wall CNTs (SWCNTs) [24][25][26]. Fracture toughness is often derived from indentation (ID) measurements, a method whose validity is contested by several authors, both for CNT/ceramic composites [27] and for ceramics [28].…”

Analytical study on the incorporation of zirconia-based ceramics with carbon nanotubes: Dispersion methods and mechanical properties

“…In particular, the main influence of CNTs should be obtained when their volume fraction exceeds the percolation threshold of the composite. On the other hand, Mazaheri and coworkers [11,29], have reported a shift of densification of the ceramics to higher temperatures in the presence of CNTs. They suggest that the flexibility of carbon nanotubes allows them to bend and pass through spaces between nanopowders and wrap around them.…”

“…Although conducting the process in a wet medium followed by a chemical surface functionalization seems to be a promising dispersion method, using mechanical forces in a dry medium of a planetary milling device has also been reported to result in the homogenous distribution of nanotubes. Mazaheri and co-workers [9][10][11][12][13] were among the very first groups that utilized a specific Turbula mixer to obtain a well-dispersed mixture from 3Y-TZP powder and carbon nanotubes. Their work was repeatable and could be confirmed when Taheri et al [9] followed the same processing conditions and could ultimately conceive a homogenous distribution of CNTs within nano zirconia powder.…”

“…The great interest in the incorporation of carbon nanotubes (CNTs) into ceramic materials stems from their remarkable mechanical, electrical and functional properties [11][12][13][14]. A combination of a high aspect ratio, excellent stiffness and strength make them prominent candidates for reinforcing a large spectrum of materials.…”

“…Considering varied processing conditions, CNTs' dispersion can be successfully operated in wet [20][21][22][23] or dry [9][10][11][12][13] media. Although conducting the process in a wet medium followed by a chemical surface functionalization seems to be a promising dispersion method, using mechanical forces in a dry medium of a planetary milling device has also been reported to result in the homogenous distribution of nanotubes.…”