  Effects on mechanical properties of the presence of either single-walled
carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) in a 3YTZP
matrix have been investigated in this work. Thus, monolithic 3YTZP and 3YTZP
containing 2.5 vol% either SWCNTs or MWCNTs were fabricated by Spark Plasma
Sintering (SPS) at 1250 C. Samples were crept at temperatures between 1100 and
1200 C and stresses between 5 and 230 MPa. Raman spectroscopy measurements
indicate the absence of severe damages in the CNTs structure after sintering
and testing. Scanning electron microscopy studies show that microstructures do
not evolve during creep tests. Mechanical results point out that monolithic
3YTZP exhibits a higher creep resistance than composites since CNTs facilitate
grain boundary sliding during high-temperature deformation. SWCNTs and MWCNTs
have a similar effect on the high temperature mechanical behavior in 3YTZP
where the bundle length and the level of dispersion of CNTs play a crucial
role.
