This heat sink is made up of aluminum and the surface is black anodized, both of which make an excellent heat dissipation rate and insulating property, resulting in a better effect in heat dissipation.
The heat sink's thermal resistance is the most important parameter to choose heat sink.
Once the maximum safe junction temperature for the equipment (Tjmax) is known, the power is going to dissipate (Pd) and the maximum ambient temperature will work at (Tamb), thus the maximum total Rth (j-a) from this expression:
Rth (j-a) = (Tjmax - Tamb)/Pd
From the manufacturer's data, useful information, such as Rth (j-c) can be found, the junction-case thermal resistance of the power equipment itself. Then add the thermal resistance of the thermal compound and/or insulating washer and this will provide the total junction to heat sink resistance. Subtract this from the maximum Rth (j-a) figure, and the maximum allowable heat sink resistance will be achieved. Then select a heat sink which will provide no more than this value of thermal resistance.