Thermally Conductive Material Design Criteria

Thermally Conductive Material Design Criteria

Thermal Conductivity

Thermal Conductivity is a property that describes the intrinsic ability of a material to conduct heat. It is commonly represented by the unit W/m.K, which measures the rate at which heat travels through a material where there is a temperature difference between two points (T1 – T2) over a specific distance (d).
Thermal Conductivity can be further derived from this formula as follows: A higher k value (W/m.K) indicates that the material is more efficient at conducting heat.

Thermal Resistance

Thermal Resistance describes the thermal properties of a material and how it resists heat at a specific thickness. Thermal resistance is proportional to the thickness of the material, but it can be affected by gaps that occur between contact surfaces.
These gaps create Contact Resistance, contributing to additional thermal resistance not represented in the above formula. Therefore, total thermal resistance in an
application is represented

Thermal Conductivity Unit Conversion Guide

There are several commonly used measurements of Thermal Conductivity. In addition to W/m.K, other potential units of measurement include cal/cm.s oC and BTU-in/hr. ft2oF.

Performance

Momentive Performance Materials designs its thermal silicones to maximize thermal conductivity of the interface material (R2), and minimize the resistance between R1 and R3 through minimized bond lines. The wetting properties of these materials also helps them fill microscopic gaps in uneven surfaces to minimize the effects of
contact resistance

Thermally Conductive Encapsulants & Potting Compounds

Momentive Performance Materials’ silicone encapsulants deliver thermal conductive performance, contributing to the long-term reliability of heat-generating electronic components. These thermal products cure to a soft rubber, gel material, and include low viscosity grades that can be used for potting applications, and higher viscosity grades that exhibit dispensing stability needed for bead formulation. Some products are also candidates as gap fillers or liquid dispensed alternatives to thermal pads.