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Development of Carbon Nanotube Reinforced Bulk Polycrystalline Ceramics with Intragranular Carbon Nanotube Reinforcement
Author(s) -
Satam Mahesh K,
Gurnani Luv,
Vishwanathe Sadavijay,
Mukhopadhyay Amartya
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14425
Subject(s) - materials science , crystallite , composite material , ball mill , carbon nanotube , grain boundary , nanotube , ceramic , microstructure , indentation , sintering , agglomerate , grain growth , abrasive , carbon nanotube metal matrix composites , crystallization , metallurgy , chemical engineering , engineering
In the bulk polycrystalline ceramic–carbon nanotube ( CNT ) composites developed to date, reinforcing CNT s have been present just at the matrix grain boundaries, with the grain interiors being nearly completely devoid of CNT ; thus severely limiting the improvements achieved in fracture and wear properties. Against this backdrop, bulk polycrystalline Al 2 O 3 ‐based composites, having multi‐walled CNT s ( MWCNT s) present within the matrix grain interiors (not just at grain boundaries), have been developed in this work for the first time. Such microstructure development has been rendered possible by an innovative, but facile, wet‐chemical synthesis route (sans ball‐milling) involving incorporation of well‐dispersed MWCNT s directly into matrix sol, followed by rapid gelation (within a few seconds) and sintering (inclusive of crystallization step). Intragranular MWCNT reinforcements (in “sol–gelled” composites) led to significant improvements in indentation‐induced crack propagation resistances and abrasive wear resistances, as compared to “conventionally” prepared Al 2 O 3 – MWCNT composites (i.e., “ball‐milled” counterpart) having the same contents of MWCNT , but present only at grain boundaries. Wear rates recorded with the “sol–gelled” Al 2 O 3 ‐2.5 vol% MWCNT are lower than those for monolithic Al 2 O 3 and “ball‐milled” counterpart by ~95% and ~90%, respectively. Such improvements, as never achieved before, are a consequence of reinforcing the matrix grain interiors with MWCNT s.