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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Thermal contact resistance between matrix and particle in composite materials measured by a thermal microscopic method using a semi-intrinsic thermocouple

Get access (open in a dialog) DOI: 10.1615/IHTC12.360
6 pages

Resumo

An improved method is presented for the thermal contact resistance (TCR) measurement between filler particle and matrix in composite materials. A modulated laser beam is focused on the particle while temperature phase lag is measured on the polymer by a specifically designed thermal probe. This device consists in a 2 µm platinum wire which in contact with the nickel thin film deposited on the polymer provides thermoelectric effects when heat is transferred from the particle to the polymer. The main features of this probe is its miniaturisation and also the low thermal contact resistance probe/polymer compared with the matrix/inclusion one. In order to estimate from these measurements the filler/matrix TCR value, we have developed theoretical models describing harmonic heat transfer in a conductive filler particle in imperfect contact with the surrounding polymer. Solutions for spherical or cylindrical inclusion were compared by the analysis of the distributions of thermal phase lag. It is found that 1D heat transfer models presents an important bias by comparison with 2D one. The relative error in the TCR measurement was analysed by taking into account the main direct sources of error which are phase lag and distance imprecisions. It was established the presence of an optimal frequency, dependent on the TCR value, with minimal error. A filler/matrix thermal contact resistance of (3.8 ± 0.6)10-5 m2K/W was found for an aluminium fibre embedded in a polybutylene terephthalate (PBT) polymer.