A thermal interface material is a thermally conductive material sandwiched between two surfaces in order to dissipate heat away from electronics. Its ability to conduct heat is called thermal conductivity, which is measured in Watts per meter Kelvin (W/m*K). Also important is the thermal resistance, which measures a material’s ability to transfer heat across an interface. This property will vary depending on the application, environment, and materials that the TIM contacts. As solids heat up, they expand at a rate proportional to the temperature increase. The coefficient of thermal expansion is a measure of this rate of change.