Phase analysis, mechanical properties and in vitro bioactivity of graphene nanoplatelet-reinforced silicon nitride-calcium phosphate composites

Dilan Bozkurt, Melis Kaplan Akarsu, Ipek Akin*, Gultekin Goller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The aim of this study is to produce highly dense Si3N4 based composites with good mechanical properties and bioactivity. Si3N4 ceramics without using sintering aids, Si3N4-HA and Si3N4-HA-GNP based composites have been produced by spark plasma sintering (SPS) at temperatures of 1525–1550°C. The effect of reinforcement type and content on the densification behavior, phase analysis, microstructural development, mechanical properties, and in-vitro bioactivity behavior of Si3N4 were systematically investigated. Monolithic Si3N4 that contains a high amount of β-Si3N4 phase (~87 wt%) was produced by nearly full densification (~99%). Hydroxyapatite (HA) was used as a starting powder during the preparation of binary and triple composites to provide bioactivity to Si3N4, and after sintering, HA transformed into tricalcium phosphate (β-TCP and α-TCP) polymorphs. The incorporation of GNPs had a positive effect on the stability of β-TCP phases at higher sintering temperatures. The improvement in indentation fracture toughness of the samples with GNP reinforcement was mainly attributable to pull-out and crack deflection mechanisms. In-vitro bioactivity of GNP added composites enhanced with increasing α-TCP content. More calcium phosphate-based particle formation was observed in Si3N4-HA-GNP composites compared to the Si3N4-HA.

Original languageEnglish
Pages (from-to)471-486
Number of pages16
JournalJournal of Asian Ceramic Societies
Volume9
Issue number2
DOIs
Publication statusPublished - 2021

Bibliographical note

Publisher Copyright:
© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of The Korean Ceramic Society and The Ceramic Society of Japan.

Keywords

  • bioactivity
  • graphene
  • Silicon nitride
  • spark plasma sintering
  • tricalcium phosphate

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