How can die-cast zinc alloy automotive communication heat sinks achieve high thermal conductivity while ensuring the formation of complex thin-walled structures?
Publish Time: 2026-02-03
With the rise of automotive intelligence and electrification, the power density of in-vehicle communication modules continues to increase, placing higher demands on heat dissipation systems: they must efficiently dissipate heat from the chips while integrating complex structures within a confined space. Die-cast zinc alloys, with their excellent fluidity, high dimensional accuracy, and near-net-shape forming capability, have become the ideal material for manufacturing such heat sinks.1. High-Flow Die Casting: Achieving Integrated Forming of Micro-Thin-Walled StructuresModern automotive communication heat sinks often require ultra-thin fins (0.5–1.2 mm), densely arranged fins, and three-dimensional curved contours, which are difficult to achieve with traditional aluminum extrusion or stamping and welding processes. Zinc alloys, with their low melting point and low viscosity, can perfectly fill complex mold cavities in high-pressure casting, achieving a high-precision, burr-free, and machining-free integrated structure. This near-net-shape forming capability not only reduces manufacturing costs but also avoids the contact thermal resistance caused by assembling multiple components. More importantly, the dense die-cast structure reduces internal porosity—by optimizing gate design and employing vacuum die-casting or local extrusion techniques, porosity can be controlled below 0.5%, significantly improving the continuity of the heat conduction path.2. Material Modification: Enhancing Intrinsic Thermal ConductivityTo compensate for the thermal conductivity shortcomings of zinc alloys, the industry is promoting material-level innovation. On the one hand, adding trace amounts of copper, aluminum, or rare earth elements to base alloys such as Zamak 3 or ZA-8 refines the grain size and reduces impurity phases, improving the matrix thermal conductivity; on the other hand, exploring high thermal conductivity composite zinc alloys, such as introducing nano-aluminum nitride or graphene microsheets as reinforcing phases. Although not yet commercially available on a large scale, laboratory data shows promising results. Furthermore, the good surface finish of zinc alloys facilitates subsequent coating with high emissivity coatings, enhancing heat radiation dissipation and indirectly improving overall heat dissipation efficiency.3. Structural Thermal Design: Compensating for Material Limitations with Geometric AdvantagesEngineers maximize the forming advantages of zinc alloys through ingenious thermodynamic structural design. For example, biomimetic fractal flow channels or gradient-thickened fins can be used to densify and thicken heat dissipation fins in areas of concentrated heat sources, while thinning and reducing weight in edge areas; alternatively, embedded heat pipes/vapor chamber interfaces can be integrated, allowing for rapid lateral heat dissipation by high thermal conductivity elements, followed by large-area convection cooling by the zinc alloy shell. This hybrid architecture of "core heat conduction + shell heat dissipation" effectively avoids the weakness of insufficient longitudinal thermal conductivity in zinc alloys. Simulations show that, for the same volume, the optimized zinc alloy heat sink's thermal resistance can approach that of ordinary extruded aluminum, fully meeting the heat dissipation requirements of 50–150W communication modules.4. Surface Functionalization: Enhancing Convection and Radiation Heat TransferThe surface of die-cast zinc alloys is easy to treat with electrophoresis, spraying, or micro-arc oxidation. By applying a high-emissivity black ceramic coating, thermal radiation efficiency can be increased by more than 30%; combined with forced air cooling, the smooth surface can also reduce wind resistance and improve the convective heat transfer coefficient. In the enclosed vehicle environment, this "passive enhancement" strategy is crucial for compensating for the disadvantages of thermally conductive materials.In summary, the die-cast zinc alloy automotive communication heat sink does not rely on the performance of a single material to succeed. Instead, it achieves an organic unity between "complex structure" and "efficient heat dissipation" through a four-pronged strategy: precision molding to ensure structural integrity, material modification to enhance thermal conductivity, thermal design to optimize heat paths, and surface treatment to improve heat transfer efficiency. It breaks through material boundaries with a systems thinking approach, providing a new paradigm for heat dissipation in highly integrated automotive electronics that combines performance, cost, and reliability.
