High‐Temperature Deformation Mechanisms in Monolithic 3 YTZP and 3 YTZP Containing Single‐Walled Carbon Nanotubes

Monolithic 3 YTZP and 3 YTZP containing 2.5 vol% of single‐walled carbon nanotubes ( SWCNT ) were fabricated by Spark Plasma Sintering ( SPS ) at 1250°C. Microstructural characterization of the as‐fabricated 3 YTZP / SWCNT s composite shows a homogeneous CNT s dispersion throughout the ceramic matrix. The specimens have been crept at temperatures between 1100°C and 1200°C in order to investigate the influence of the SWCNT s addition on high‐temperature deformation mechanisms in zirconia. Slightly higher stress exponent values are found for 3 YTZP / SWCNT s nanocomposites ( n ~2.5) compared to monolithic 3 YTZP ( n ~2.0). However, the activation energy in 3 YTZP ( Q  = 715 ± 60 kJ/mol) experiences a reduction of about 25% by the addition of 2.5 vol% of SWCNT s ( Q  = 540 ± 40 kJ/mol). Scanning electron microscopy studies indicate that there is no microstructural evolution in crept specimens, and Raman spectroscopy measurements show that SWCNT s preserved their integrity during the creep tests. All these results seem to indicate that the high‐temperature deformation mechanism is grain‐boundary sliding ( GBS ) accommodated by grain‐boundary diffusion, which is influenced by yttrium segregation and the presence of SWCNT s at the grain boundary.