Treeing phenomena in epoxy/alumina nanocomposite and interpretation by a multi-core model

Toshikatsu Tanaka*, Akira Matsunawa, Yoshimichi Ohki, Masahiro Kozako, Masanori Kohtoh, Shigemitsu Okabe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)


Epoxy/alumina nanocomposites were prepared in laboratory to be shaped into specimens suitable for treeing experiments. It was elucidated that treeing breakdown strength would increase, if epoxy resins were nanostructured with nano-fillers such as nano boehmite alumina fillers with their loading from 5 to 10 wt%. Tree initiation time is prolonged, as the filler content increases. Tree morphology is different between base resin and its nanocomposite specimens. A new crossover phenomenon is recognized, i.e. thin channels extend more quickly to reach the opposite electrode in nanocomposites than in pure epoxy above ac 20 kV (1000 kV/mm in the tip of the needle), while they show slower growth in nanocomposites than in pure epoxy below ac 15 kV (750 kV/mm). It should be noted that the reach of such thin channels to the grounds does not mean breakdown, but such formed trees grow in width at later stage to cause final breakdown. Treeing phenomena obtained are analyzed and interpreted by a multi-core model to cover various findings of treeing phenomena in nanocomposites.

Original languageEnglish
Pages (from-to)1128-1135
Number of pages8
JournalIEEJ Transactions on Fundamentals and Materials
Issue number11
Publication statusPublished - 2006


  • Multi-core model
  • Nanocomposite
  • Nanodielectrics
  • Polymer nanocomposite
  • Treeing
  • Treeing breakdown

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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