On the thermal conductivity of spark plasma sintered alumina hybrid nanocomposites: Estimation modeling and experimental validation

M.U Siddiqui,N Saheb,U Hayat,Abul Arif

doi:10.2298/sos1901101s

M.U Siddiqui, N Saheb + Show 2 more

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https://doi.org/10.2298/sos1901101s

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Abstract

In the current work, an improved model to estimate the thermal conductivity of spark plasma sintered nanocomposites is presented. In the developed model, the thermal conductivity of the matrix was modeled as a function of the average matrix crystallite size rather than taking a constant matrix thermal conductivity. The model has been validated against experimentally measured thermal conductivity of Al2O3-SiC-CNT hybrid nanocomposites. Using the experimental and modeling results, it was shown that the addition of SiC and CNT inclusions to alumina resulted in a decrease in its thermal conductivity. The main reason for this decrease was found to be the reduction in the thermal conductivity of the alumina matrix itself because of the reduction in the crystallite size. Additional reduction in the composite thermal conductivity was due to the matrix-inclusion interface resistance and porosity. The predicted and measured thermal conductivities were found to be in good agreement.

Highlights

The brittleness of monolithic ceramics had limited their use in many applications [1]
The average crystallite size of the monolithic alumina sample sintered at a temperature of 1500 oC and a pressure of 50 MPa for 10 min was 125 nm
The increase in SiC content to 10 wt.% led to a further decrease in the crystallite size which reached 88 and 85 nm for Al2O3-10SiC-1CNT and Al2O3-10SiC-2CNT composites, respectively

Summary

Introduction

The brittleness of monolithic ceramics had limited their use in many applications [1]. Removal of this limitation was made possible through the development of composites [2], nanocomposites [3], and hybrid nanocomposites [4, 5]. Hybrid ceramic nanocomposites are advanced ceramic materials obtained by reinforcing a ceramic matrix with two nano-reinforcements that have different morphologies and/or attributes. The design goal for the development of these composites is to obtain materials with improved mechanical and/or functional properties [6, 7]. Alumina is a well-known advanced ceramic material with wide-ranging applications [8]. Analysis of literature shows that the majority of research work published on alumina hybrid nanocomposites has been devoted to the characterization of the microstructure and the

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