Diamond can meet the extremely demanding requirements of thermal management applications in two main forms: diamond thin film and diamond as a thermally conductive filler. Currently, thermally conductive diamond fillers are primarily used in metal-matrix diamond composites (MMCs), such as diamond-copper/diamond-aluminum composites, and thermally conductive interface materials (TIMs, focusing here on diamond thermally conductive gels).
Metal-matrix diamond composites
Diamond, as a reinforcing phase, possesses extremely high thermal conductivity (reaching 600-2200 W/m·K at room temperature), making metal-matrix diamond composites excellent in thermal conductivity. For example, a diamond/copper composite with a diamond volume fraction of 35% achieves a thermal conductivity of 602 W/m·K. This high thermal conductivity makes it ideal for applications requiring efficient heat dissipation, such as electronic packaging and high-power electronic devices. Diamond's low thermal expansion coefficient, when combined with a metal matrix (such as copper or aluminum), effectively reduces the thermal expansion coefficient of the material. This property helps reduce dimensional change during temperature fluctuations, improving device stability and reliability.
Diamond Thermal Conductive Gel
Like other thermally conductive gels, the performance of diamond thermally conductive gels depends largely on the maturity and quality of their preparation process. Factors such as filler particle size, filler volume fraction, and modification process all significantly impact the gel's overall thermal conductivity.
First, the diamond particle size must be kept small (less than 10 microns), otherwise it will be difficult to form an effective thermal chain.
Second, the diamond particle filler volume fraction must be kept neither too large nor too small. If it is too small, the contact area will be reduced, making it equally difficult to form an effective thermal chain. If it is too large, the gel will not be able to fully wet the diamond particle surface, resulting in voids and thus affecting thermal conductivity.
Finally, modification is essential for this type of thermally conductive gel filler. Otherwise, these highly surface-active particles will easily agglomerate, making it difficult to achieve uniform dispersion in the organic polymer resin, resulting in reduced gel performance.
