How a PHD says no powder coat on barrels:
Powder Coatings Clinic
Marek Urban, Ph.D.
University of Southern Mississippi-Hattiesburg
Thermal conductivity of powder coatings
Q: I would like to know what the thermal conductivity of powder coatings is. I want to determine if a powder coating applied to an aluminum heat sink will degrade the effect to dissipate the heat. B.J., Virginia Beach, Va.
A: Thermal conductivity of powder coatings is more or less the same as any other thermosetting polymer network, which compared with other nonpolymeric materials is low. The term that is often used is thermal diffusivity,which is a function of thermal conductivity, heat capacity, and density. Thermal diffusivity is also a function of temperature, which may vary from system to system; that is, it may decrease, increase, or not change with temperature because thermal conductivity and heat capacity may exhibity opposite trends. The main difficulty is that thermal conductivity and heat capacity cannot be separated experimentally.
While the above concepts apply to polymeric networks, one may alter thermal diffusivity by using highly conductive additives, like metallic pigments and other nano-particles that may effectively alter thermal diffusivity and, subsequently, thermal conductivity and heat capacity. In all cases, not only the pigment type but also the pigment volume content (PVC) will create another opportunity for altering thermal conductivity and heat resistance.
