Thermal conductivity improvment of copper-carbon fiber composite by addition of an insulator : calcium hydroxide

Samuel Couillaud (1) , Yong Feng Lu , Jean-François Silvain (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

The effects of adding calcium hydroxide (Ca(OH)2) to a copper-CF (30 %) composite (Cu-CF(30 %)) were studied. After sintering at 700 °C, precipitates of calcium oxide (CaO) were included in the copper matrix. When less than 10 % of Ca(OH)2 was added, the thermal conductivity was similar to or higher than the reference composite Cu-CF(30 %). A thermal conductivity of 322 W m−1 K−1 was measured for the Cu-Ca(OH)2(3 %)-CF(30 %) composite. The effects of heat treatment (400, 600, and 1000 °C during 24 h) on the composite Cu-Ca(OH)2(3 %)-CF(30 %) were studied. At the lower annealing temperature, CaO inside the matrix migrated to the interface of the copper matrix and the CF. At 1000 °C, the formation of the interphase calcium carbide (CaC2) at the interface of the copper and CFs was highlighted by TEM observations. Carbide formation at the interface led to a decrease in both thermal conductivity (around 270 W m−1 K−1) and the coefficient of thermal expansion (CTE (10.1 × 10−6 K−1)).

Domaines: Matériaux

Samuel Couillaud, Yong Feng Lu, Jean-François Silvain. Thermal conductivity improvment of copper-carbon fiber composite by addition of an insulator : calcium hydroxide. Journal of Materials Science, 2014, 49 (16), pp.5537-5545. ⟨10.1007/s10853-014-8246-8⟩. ⟨hal-01016506⟩