Microstructure and fracture toughness of Si₃N₄ + graphene platelet composites

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• 作者：Já ; n Dusza^a ; Jerzy Morgiel^b ; Annamá ; ria Duszová ; ^a ; Lenka Kvetková ; ^a ; ^{lenka.forraiova@mail.t-com.sk} ; Martin Nosko^c ; Pé ; ter Kun^d ; Csaba Balá ; zsi^d
• 关键词：Si3N4 ; Nanocomposites ; Platelets ; Graphene ; Toughness and toughening
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：September, 2012
• 卷：32
• 期：12
• 页码：3389-3397
• 文件大小：1715 K

摘要

Silicon nitride + 1 wt%graphene platelet composites were prepared using various graphene platelets (GPLs) as filler. The influence of the addition of GPLs on the microstructure development and on the fracture toughness of Si₃N₄ + GPLs composites was investigated. The GPLs with thickness from 5 nm to 50 nm are relatively homogeneously distributed in the matrix of all composites, however overlapping/bundle formation of GPLs was found, containing 2-4 platelets as well. The single GPLs and overlapped GPLs are located at the boundaries of Si₃N₄, and hinder the grain growth and change the shape of the grains. The fracture toughness was significantly higher for all composites in comparison to the monolithic Si₃N₄ with the highest value of 9.9 MPa m^0.5 for the composite containing the GPLs with smallest dimension. The main toughening mechanisms originated from the presence of graphene platelets, and responsible for the increase in the fracture toughness values are crack deflection, crack branching and crack bridging.