Microstructure and mechanical properties of single wall carbon nanotube reinforced yttria stabilized zircona ceramics

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

“…This is in agreement with the percolation thresholds measured both for SWCNT/YSZ composites (< 0.4 vol.%) [25] and MWCNT/YSZ composites (< 0.75 vol.%) [43]. The electrical conductivity for C0.5 is much higher than that reported by most authors for composites with the same carbon content but it is lower than that reported by Shin et al Ukai et al [43] could explain this difference.…”

“…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].…”

“…Nevertheless, such a microstructure could be preferable in order to obtain a material less sensitive to ageing, a consequence of the tetragonal-to-monoclinic phase transformation in humid environment [13,30]. Thirdly, some works have also shown that CNT/zirconia composites with 100 nm grains show a very low friction coefficient against alumina [20] or a low wear rate against Si 3 N 4 [25].…”

Nanoindentation and fracture toughness of nanostructured zirconia/multi-walled carbon nanotube composites

“…Values up to 13 MPa.m 1/2 have been reported for the addition of 1 wt. % SWNTs [10]. Other authors have found that the increase in indentation K Ic only occurs for the addition of relatively small CNTs content: 0.5 wt.…”

“…%) ([6,7,9]) or above relatively high content, the hardness decreases with the addition of CNT or CNF to monolithic zirconia [8,10,11,[14][15][16][17][18]. One exception is the work of Mazaheri et al [7], who reported a slight increase for the addition of 5 wt.…”