6.1 Tailoring by Component Selection 163 Table 6.2.Properties of metals,carbons and ceramics Material Density Thermal Electrical Elastic CTE (g/cm3) conductivity resistivity modulus (10-6/K) (w/(mK)) (2cm) (GPa) Aluminum 2.70 237 2.65×10-6 70 23.1 Copper 8.96 401 1.68×10-6 110-128 16.5 Molybdenum* 10.22 142 5.2×10-6 320 4.9 Tungsten* 19.3 155 5.3×10-6 400 4.5 Kovar 8.35 17 49×10-5 159 5.2 (Fe-Ni29-Col7) Invar 8.05 10.5 8.2×10-5 141 12 (Fe-Ni36) Carbon fiberb 1.76 P 1.8×10-3 231 -0.60 (high strength) Carbon fiber 2.17 640 2.2×10-4 827 -1.45 (high modulus) Silicon 3.1 120 102-106 410 4.0 carbide (SiC) Silicon nitride 3.29 30 310 3.3 (SisN4) Aluminum 3.26 140-180 >1014 330 4.5 nitride (AIN) Aluminum 3.89 35 >1014 375 8.4 oxide(Al2O3) Boron nitride 1.9 121 >1014 -0.46 (hexagonal) Titanium 4.50 96 10-5 565 6.4 diboride(TiB2) Zirconium 6 >1010 200 10.3 oxide(ZrO2), Y2O3 stabilized a Metal;b carbon;ceramic of the carbon or ceramic filler)and a high elastic modulus(although not as high as that of the carbon or ceramic filler),in addition to high thermal and electrical conductivities(although not as high as those of the metal matrix).When copper is used as the matrix,the composite also allows a reduction in density (although the density does not become as low as that of the carbon or ceramic filler). The combination of low CTE and high thermal conductivity is particularly attractive for electronic packaging,such as heat sinks,housings,substrates,lids, etc.The combination of high electrical and thermal conductivity and hardness is particularly attractive for welding electrodes,motor brushes,and sliding contacts. Among the ceramic fillers listed in Table 6.2,titanium diboride and silicon carbide are most attractive due to their high elastic moduli.This is an important factor for strengthening the composite.Among the ceramic fillers listed,aluminum nitride is most attractive due to its high thermal conductivity,although silicon carbide and hexagonal boron nitride have quite high thermal conductivities.One6.1 Tailoring by Component Selection 163 Table 6.2. Properties of metals, carbons and ceramics Material Density Thermal Electrical Elastic CTE (g/cm3) conductivity resistivity modulus (10−6/K) (W/(m K)) (Ωcm) (GPa) Aluminuma 2.70 237 2.65 × 10−6 70 23.1 Coppera 8.96 401 1.68 × 10−6 110–128 16.5 Molybdenuma 10.22 142 5.2 × 10−6 320 4.9 Tungstena 19.3 155 5.3 × 10−6 400 4.5 Kovara 8.35 17 4.9 × 10−5 159 5.2 (Fe-Ni29-Co17) Invara 8.05 10.5 8.2 × 10−5 141 1.2 (Fe-Ni36) Carbon fiberb 1.76 8 1.8 × 10−3 231 −0.60 (high strength) Carbon fiberb 2.17 640 2.2 × 10−4 827 −1.45 (high modulus) Silicon 3.1 120 102–106 410 4.0 carbide (SiC)c Silicon nitride 3.29 30 / 310 3.3 (Si3N4) c Aluminum 3.26 140–180 > 1014 330 4.5 nitride (AlN)c Aluminum 3.89 35 > 1014 375 8.4 oxide (Al2O3) c Boron nitridec 1.9 121 > 1014 / −0.46 (hexagonal) Titanium 4.50 96 10−5 565 6.4 diboride (TiB2)c Zirconium 6 2 > 1010 200 10.3 oxide (ZrO2)c, Y2O3 stabilized a Metal; b carbon; c ceramic of the carbon or ceramic filler) and a high elastic modulus (although not as high as that of the carbon or ceramic filler), in addition to high thermal and electrical conductivities (although not as high as those of the metal matrix). When copper is used as the matrix, the composite also allows a reduction in density (although the density does not become as low as that of the carbon or ceramic filler). The combination of low CTE and high thermal conductivity is particularly attractive for electronic packaging, such as heat sinks, housings, substrates, lids, etc. The combination of high electrical and thermal conductivity and hardness is particularly attractive for welding electrodes, motor brushes, and sliding contacts. Among the ceramic fillers listed in Table 6.2, titanium diboride and silicon carbide are most attractive due to their high elastic moduli. This is an important factor for strengthening the composite. Among the ceramic fillers listed, aluminum nitride is most attractive due to its high thermal conductivity, although silicon carbide and hexagonal boron nitride have quite high thermal conductivities. One