CarbAlTM material is a carbon-based metal nanocomposite (CAl) comprised of 80% carbonaceous matrix and a dispersed metal component of 20% aluminum.
The carbonaceous material is comprised of an isotropic thermally conductive carbonaceous matrix and additional anisotropic thermally conductive carbonaceous matter. The combination of the two carbonaceous phases achieves partial directionality whereby the heat is diffused in a preferred direction.
In the table below the properties of the CarbAlTM composite are compared with silicon carbide – aluminum composites, aluminum and copper. High thermal diffusivity and low specific heat of the CarbAlTM composite contribute to a substantial increase in thermal conductivity.
|
| |
SiC |
Aluminum |
Copper |
CarbAlTM |
Al-SiC(55) |
Al-SiC(70) |
Al1060H12 |
C1020 |
Al-C400 |
Thermal diffusivity |
cm2/sec |
- |
0.88 |
0.95 |
1.7 |
2.55 |
Thermal conductivity |
W/mK |
240 |
270 |
203 |
390 |
425 |
Coefficient of thermal expansion |
1/K |
10*10-6 |
7*10-6 |
24*10-6 |
17*10-6 |
7*10-6 |
Electric resistivity |
μΩ•cm |
3.0 |
4.0 |
2.8 |
1.7 |
4.0 |
Specific Heat |
J/gK |
1.0 |
1.0 |
1.0 |
0.5 |
0.75 |
Specific Gravity |
g/cm3 |
2.9 |
3.0 |
2.7 |
8.9 |
2.3 |
Bending strength |
MPa |
350 |
380 |
80 |
350 |
40 |
Young's Modulus |
GPa |
200 |
265 |
70 |
119 |
12 |
The new highly heat transmissive CarbAlTM material can be provided in rectangular blocks and other shapes based on form factor requirements of an application. The material is not hard and can be sliced easily to very thin samples that interface between the local point of heat creation and a heat sink or other heat dissipative device.
In the following example of how CarbAlTM material can be used, substrate A is comprised of the CarbAlTM carbon-based metal composite material that is joined to a ceramic insulating surface B via an adhesive layer C. The adhesive layer can be a synthetic resin, solder, metal-brazing material, etc. Circuit elements and other parts (D) are placed on the ceramic insulating substrate. In other applications the ceramic insulating material can be replaced by any type of substrate or insulating film that has the circuits and parts such as semiconductor elements, resistors, capacitors, etc. distributed on it.
