Field-assisted/spark plasma sintering behavior of CNT-reinforced zirconia composites: A comparative study between model and experiments

In the current investigation, 8 mol.% fully yttria-stabilized zirconia (8YSZ) mixed with different fractions (0, 1.3, 2.6, and 7.6 vol.%) of multiwalled carbon nanotubes (CNT) was processed using the field-assisted sintering technique (FAST)/spark plasma sintering (SPS) method. The sintering behavior of the CNT-containing composites was studied by comparing densification rates as a function of volume content during isothermal sintering. The role of CNTs in densification kinetics and microstructure was investigated. Using the concept of constrained sintering, CNTs were found to instigate effects similar to those of rigid inclusions with respect to the densification process. Good agreement was found between the theoretical model calculations and the experimental measurements.