Phase transformation behavior of ZrO2 by addition of carbon nanotubes consolidated by spark plasma sintering

Commercial ZrO2/carbon nanotube (CNT) composite powders were sintered by spark plasma sintering (SPS). The densification behavior during SPS was investigated by analysis of recorded shrinkage plots, and addition of CNTs was found to alter the sintering mechanism. Moreover, the addition of CNTs could also lead to refined grain size, improved fracture toughness as well as reduced Vickers hardness. Raman spectroscopy revealed an initially decreasing and then increasing tendency for the tetragonal to monoclinic phase transformation during indentation of the composites.