Liquid‐Phase Assisted Engineering of Highly Strong SiC Composite Reinforced by Multiwalled Carbon Nanotubes

Abstract

Despite the ultrahigh intrinsic strength of multiwalled carbon nanotube (MWCNT), the strengthening effect on ceramic matrix composite remains far from expectation mainly due to the weak load transfer between the reinforcement and ceramic matrix. With the assistance of the in situ pullout test, it is revealed that the liquid‐phase sintering (LPS) can serve as a novel strategy to achieve effective load transfer in MWCNT reinforced ceramic matrix composites. The YAlO 3 formed liquid phase during spark plasma sintering of SiC composite greatly facilitates radical elastic deformation of MWCNT, leading to highly increased interfacial shear strength (IFSS) as well as interlayer shear resistance (ISR) of nested walls. The liquid phase with superior wettability can even penetrate into the defects of MWCNT, which further increases the ISR of MWCNT. Moreover, the first‐principles calculation indicates that the oxygen terminated YAlO 3 phase displays much stronger bonding compared with SiC matrix, which is also responsible for the large IFSS in the composite. As a result, as high as 30% improvement of bending strength is achieved in the composite with only 3 wt% MWCNT in comparison to the monolithic ceramic, manifesting the unprecedented strengthening effect of MWCNT assisted by LPS.

Zirconia‐containing glass‐ceramics: From nucleating agent to primary crystalline phase

“…The SiO 2 in the raw ZrO 2 -SiO 2 powder could react with this sintering additive, leading to the formation of a liquid phase with a low eutectic point. 122,123 The influence of liquid phase formation on the glass-densification behavior is interesting. The coarsening behavior of ZrO 2 nanocrystallites during sintering and crystallization would also be affected by the presence of the liquid phase.…”

“…Their goal was to investigate pressureless sintering by LPS with the help of ternary sintering aids (AlCl 3 , YCl 3 , and CaCl 2 ). The SiO 2 in the raw ZrO 2 –SiO 2 powder could react with this sintering additive, leading to the formation of a liquid phase with a low eutectic point 122,123 . The influence of liquid phase formation on the glass‐densification behavior is interesting.…”

Liquid‐phase sintering of ZrO2‐based nanocrystalline glass–ceramics achieved by multielement co‐doping

“…In this study, we are aiming to sinter the NCGC by LPS via adding a ternary sintering additive, that is, AlCl 3 , YCl 3 , and CaCl 2 . It is possible that this ternary sintering additive would react with the SiO 2 component in the raw ZrO 2 –SiO 2 powder to form a liquid phase with a low eutectic point 22,23 . We are interested in investigating the effects of LPS on the densification behavior of the glass–ceramic.…”

“…It is possible that this ternary sintering additive would react with the SiO 2 component in the raw ZrO 2 -SiO 2 powder to form a liquid phase with a low eutectic point. 22,23 We are interested in investigating the effects of LPS on the densification behavior of the glass-ceramic. The presence of the liquid phase would also affect the coarsening behavior of ZrO 2 nanocrystallites during sintering and annealing.…”