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Aluminum Silicon Carbide - AlSiC (Al/SiC)
A composite material of Aluminum (Al) metal and Silicon Carbide(SiC). Composite materials are developed to achieve properties that are intermediate to both constituents. Aluminum Silicon Carbide (hereafter AlSiC) is a material that has properties that are ideal for thermal management of electronic devices and systems (thermal conductivity/controlled thermal expansion) and structural applications (low density, high strength and stiffness).

Thermal Properties
Thermal Management is a term used by the electronics industry that refers to a material or systems ability to dissipate heat to improve the reliability of the electronic systems or devices. In materials we are concerned primarily with the thermal conductivity value of the material as well as the thermal expansion coefficient. The thermal conductivity value should be as high as possible. Copper has a very high thermal conductivity value at about 400 W/mK and is a good heat sink material. Copper can be used as an effective thermal dissipation material provided that the high thermal expansion value of Cu does not effect the thermal path between the device and Cu heat sink.
 * 1) Thermal Management

AlSiC, Copper Molybdenum, and Copper Tungsten are considered good thermal management materials since their thermal conductivity values are high and the thermal expansion values of these materials are matched well with common Integrated Circuit (hereafter IC) materials and other materials that are used in electronic assemblies.

Is the measurement of a materials ability to conduct heat. For electronics thermal management the value of the property needs to be as high as possible. Listed in Table 1 below are thermal conductivities for the most common thermal management materials and heat sinks as compared to AlSiC.
 * 1) Thermal Conductivity

Is the measurement of a material's expansion (contraction) on heating and cooling. For thermal management in electronics it is best if this value be compatible with the materials and heat generating devices to minimize thermally induced stresses. These differential stresses can result in the IC device being put into tension causing delamination (separation) between the heat sink and the device interrupting the thermal path or cracking of the IC ultimately resulting in failure.
 * 1) Thermal Expansion or Coefficient of Thermal Expansion (hereafter CTE)

AlSiC is a composite of two materials 1) Aluminum metal which has a thermal conductivity value of 150 - 200 W/mK, and a CTE value of 23 ppm/oC 2) Silicon Carbide (SiC) which has a thermal conductivity of 200 - 230 W/mK and a CTE value of 3.4 ppm/oC. Combining these materials results in thermal properties intermediate to both materials which roughly follows a rule of mixtures value. CTE is more strongly influenced by changes in the SiC to Al metal ratio. In general for thermal management, ratios of 55 - 65 volume percent work best and are most cost effectively produced.
 * 1) Influence of AlSiC Composition on Thermal Properties

Physical Properties

 * 1) Density
 * 2) Strength & Stiffness
 * 3) Influence of Composition on Physical Properties

Fabrication Techniques

 * 1) Pressure Infiltration
 * 2) Squeeze Casting
 * 3) Capillary Infiltration
 * 4) Press and Sinter