Effective Thermal Conductivity and Thermal Resistance of Electroless Copper Plated Carbon Fiber and Fe Composite

Abstract

The effective thermal conductivity (TC) of copper plated carbon fiber (C_f-Cu)/Fe composites is significantly influenced by the anisotropic TC of C_f-Cu and the interfacial thermal resistance. TC of the composite under the layer-in-parallel (ROM) and the effective medium approximation (EMA) models was calculated, and the finite element volume method is used to simulate the thermal distribution of the elements on the 2D section to obtain the simulated TC. By comparing the calculated TC, the simulated TC, and the measured TC, the degree of influence of the porosity of volume fraction, orientation, and aspect ratio of the C_f-Cu on the TC of the composite was investigated. The orientation and aspect ratio of C_f-Cu are the main factors affecting the TC of the composites. The thermal resistances under the ROM model and the EMA model are 2.08–3.6 × 10⁻⁸ m² K W⁻¹ and 2.56–4.26 × 10⁻⁸ m² K W⁻¹, respectively. When the volume fraction of C_f-Cu is 20%, the contact thermal resistance and the negatively oriented C_f-Cu decrease the TC and the positively oriented C_f-Cu increases the TC cancel each other out. Both measured TC and simulated TC reach the maximum value, 68.89 W m⁻¹ K⁻¹ and 71.02 W m⁻¹ K⁻¹, respectively. When the volume fraction of C_f-Cu exceeds 20%, the reduction effect of contact thermal resistance and negatively oriented C_f-Cu on TC dominates.

Fig. 1 Factors that hinder the heat conduction of composites. Contact thermal resistance, R₁₂₃ = R₁ + R₂ + R₃, voids and Fe in contact with each other. voids, R₄, orientation of C_f-Cu, R₅.