Effect of high SWNT content on the room temperature mechanical properties of fully dense 3YTZP/SWNT composites

Mechanical and electrical properties of low SWNT content 3YTZP composites

“…This tendency is usually linked to a decrease in the composite density, 11 an increase in nanotube agglomeration 17 or a weakening of interfacial bonding when the grains are wrapped by CNT and, therefore, the direct contact area and bonding force among grains decrease with increasing CNT content. 12, 13 In this study, fully densified composites have been obtained, and the increase in the surface density of agglomerates (Table 2) does not play a fundamental role in the evolution of hardness when increasing SWNT content. Thus, it is clear that the incorporation of low SWNT content in the ceramic matrix minimizes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 12 the SWNT weakening effect on interfacial cohesion between ceramic grains observed in composites with high SWNT content.…”

“…The presence of these agglomerates or clusters has been previously reported in CNT/ceramic matrix composites. 13,19,27,31,32 Low-magnification SEM micrographs (Fig. 3) illustrate the arrangement and morphology of SWNT agglomerates in the studied composites.…”

Comparative study on high temperature mechanical behavior in 3YTZP containing SWCNTs or MWCNTs

“…Then SWCNTs seem to be better dispersed throughout the 3YTZP matrix than MWCNTs. The reason could come from differences in the functionalization process undergone by both types of CNTs, since SWCNTs were COOH functionalizated following the same routine than Poyato et al [10], and MWCNTs were provided already functionalizated. Moreover, the larger bundle length and diameter of MWCNTs compared to SWCNTs could favor the formation of agglomerates.…”

“…On the one hand, commercially available 90 % purified SWNTs, with a typical bundle length of 0.5-1.5 m and diameter between 4-5 nm, were provided by Carbon Solutions Inc. (Riverside, CA). They were COOH-functionalizated following the same routine than Poyato et al [10], although at the end of the routine the acid-treated SWCNTs were freeze-dried instead of being dried on hot plate. On the other hand, it has been used commercial COOH-functionalized MWCNTs (purity > 95 %), with 15±5 nm in diameter and between 1 and 5 m in length.…”

“…Mazaheri et al [12] reported that fracture toughness, measured by VIF, improved by a factor of two in 3YTZP containing 0.5-5 wt% MWCNTs compared to monolithic 3YTZP, whereas Poyato et al [10] found a decrease in hardness and fracture toughness when increasing the SWCNTs content up to 10 vol% in 3YTZP/SWCNTs composites.…”