The effect of graphene nanoplatelets on the thermal and electrical properties of aluminum nitride ceramics

Abstract

The thermal conductivity () of AlN (2.9 wt. % of Y 2 O 3 ) is studied as a function of the addition of multilayer graphene (from 0 to 10 vol. %). The  values of these composites, fabricated by spark plasma sintering (SPS), are independently analyzed for the two characteristic directions defined by the GNPs orientation within the ceramic matrix; that is to say, perpendicular and parallel to the SPS pressing axis. Conversely to other ceramic/graphene systems, AlN composites experience a reduction of  with the graphene addition for both orientations; actually the decrease of  for the in-plane graphene orientation results rather unusual. This behavior is conveniently reproduced when an interface thermal resistance is introduced in effective media thermal conductivity models. Also remarkable is the change in the electrical properties of AlN becoming an electrical conductor (200 S m -1 ) for graphene contents above 5 vol. %.

Low percolation threshold in highly conducting graphene nanoplatelets/glass composite coatings

“…The obtained critical GNP percolation volume fraction (V h,c = 0.0118) is within the lowest reported up to now for graphene/ceramic composites (Figure 5b), which show critical volume filler contents for percolation ranging between 0.38 and 2.0 % for rGO containing composites [7][8][9] and from 2.0 up to 9.0 for composites with thicker GNP [8,10,30,31]. Therefore, this limit appears obviously related to the distribution and dispersion of the fillers.…”

From bulk to cellular structures: A review on ceramic/graphene filler composites

“…K  increases above 30 % were also stated for B 4 C/GNP[44,81] composites(Figure 16b), while irrelevant rises and even decreases on K  were reported for Al 2 O 3 /GNP[75] and AlN/GNP[70,83] composites, respectively. This decrease in thermal conduction for the inplane direction has been explained in a recent work by the existence of matrix/graphene interfacial thermal resistances[70]. FromFigure 16c, increasing K  /K || values with the GNP content (within the range of ~2.0-4.0) are reported for ceramic…”

“…In a recent paper by some of the present authors[70], the thermal behaviour of AlN/GNP materials in both directions has been conveniently reproduced by introducing in the effective media thermal conductivity model a contact thermal conductance (h c ) of  3 x 10 8 W m -2 K -1 at the AlN/GNP interface. This value agrees with calculations done for the…”

Research on the interface properties and strengthening–toughening mechanism of nanocarbon-toughened ceramic matrix composites

“…have excellent thermal, electrical, and mechanical properties. Extensive research has shown that nanocarbon can enhance many properties of ceramics, for example, the mechanical, frictional [6][7][8][9], electrical [10][11][12][13], and thermal properties [14][15][16]. As a result, nanocarbon is regarded as an ideal reinforcing phase in ceramic matrix materials.…”