Zinc die casting offers faster production cycles, tighter dimensional tolerances, and smoother surface finishes. On the other hand, aluminum die casting stands out for its lightweight, high strength, excellent heat resistance, and superior corrosion resistance. Choosing the proper process depends on factors such as product performance requirements, intended application, and budget.
This article offers a detailed comparison between zinc die casting and aluminum die casting. We’ll cover material properties, die casting processes, mechanical performance, surface finishing, and production costs, helping you make an informed decision for your next project.
Material Properties Comparison
Zinc Alloys
Zinc alloy die castings are dense (around 6.7 g/cm³), dimensionally stable, and impact-resistant.
They are ideal for intricate structures and die casting parts with tight tolerances.
The low melting point of zinc allows for efficient processing, making it especially suitable for small, precision-critical components with high surface quality requirements.
Aluminum Alloys
Aluminum die casting components are much lighter, with a density of about 2.7 g/cm³.
They offer an excellent strength-to-weight ratio, which makes them perfect for applications requiring reduced weight without compromising structural integrity.
Commonly used in the automotive die casting and electronics industries, aluminum alloys deliver strong performance, corrosion resistance, and thermal stability.
Comparison Table: Zinc vs. Aluminum Material Properties
|
Property |
Zinc Alloys | Aluminum Alloys |
|
Density (g/cm³) |
~6.7 | ~2.7 |
|
Melting Point |
Low | Higher |
| Strength-to-Weight Ratio | Moderate |
Excellent |
| Dimensional Stability | High |
Moderate |
| Corrosion Resistance | Moderate |
Excellent |
Differences in Die Casting Processes
Zinc Die Casting
Zinc die casting typically uses the hot chamber die casting machine. Thanks to zinc’s low melting point, the injection system sits directly in the molten metal.
This allows for faster cycle times and greater production efficiency.
Aluminum Die Casting
The aluminum die casting process uses the cold chamber method due to aluminum’s higher melting point.
The molten aluminum is poured into the injection chamber from an external furnace.
This slows down production but protects the machine components from heat-related damage.
Process Differences: Zinc vs. Aluminum
|
Feature |
Zinc Die Casting | Aluminum Die Casting |
|
Process Method |
Hot Chamber | Cold Chamber |
|
Cycle Time |
Faster |
Slower |
| Energy Efficiency | Higher |
Lower |
| Tool Wear | Minimal |
Higher |
Mechanical Properties and Durability
Strength
Take Zamak 3 as an example, its tensile strength is about 280 MPa, its yield strength is 210 MPa, its elongation reaches 8%, and its hardness is around 82 HB. It strikes a good balance between strength and ductility.
ADC12, a typical aluminum die casting material, has a tensile strength of about 310 MPa, a yield strength of 150 MPa, an elongation of 3.5%, and a hardness of 75 HB. It offers a strong strength-to-weight ratio but is slightly less ductile compared to zinc.
Mechanical Properties Comparison
|
Property |
Zamak 3 (Zinc) | ADC12 (Aluminum) |
|
Tensile Strength |
~280 MPa | ~310 MPa |
|
Yield Strength |
~210 MPa |
~150 MPa |
| Elongation | ~8% |
~3.5% |
| Hardness (HB) | ~82 |
~75 |
Heat Resistance
Zinc alloys are not ideal for high-temperature environments. Extended heat exposure can reduce performance, as zinc’s microstructure breaks down, causing creep, softening, and dimensional instability.
Aluminum performs well in high-heat and outdoor conditions. Its high thermal conductivity makes it a reliable choice for heat dissipation die casting aluminum components like LED housings and engine parts.
Corrosion Resistance
Aluminum provides better corrosion resistance in humid, marine, or chemically aggressive settings. It naturally forms a dense, stable oxide film that protects the surface.
Zinc forms a looser, less stable oxide layer, which offers limited long-term protection. As a result, zinc die casting parts will corrode more easily over time.
Surface Quality and Treatment
Surface Quality
Zinc castings deliver a smoother, more uniform surface straight from the mold. Their low melting point and excellent flow characteristics allow for sharp details without post-processing.
Aluminum cools quickly and is prone to issues like porosity and surface imperfections. It often requires additional finishing, such as grinding or polishing, to meet appearance standards.
Surface Finishes
Zinc die castings are highly suitable for electroplating. They can be finished with chrome, nickel, and other decorative coatings to enhance both aesthetics and corrosion resistance.
Aluminum supports a range of finishes like powder coating and painting. However, due to its stable oxide layer, surface pretreatments like sandblasting are typically needed to improve coating adhesion and durability.
Cost Analysis
Zinc die casting molds last longer, often over a million cycles, due to lower operating temperatures. Less energy is required, and mold wear is minimal, resulting in lower production costs.
In contrast, aluminum die casting operates at higher temperatures. Molds experience more thermal stress, leading to frequent maintenance and shorter tool life, which increases long-term costs.
Size and Volume
Zinc die casting is ideal for small, complex parts with high accuracy needs. It’s especially cost-effective in high-volume production runs.
Aluminum is better suited for larger components requiring strength and low weight. It becomes more economical in medium-volume production settings.
Industry Applications
Zinc Die Casting Applications
Electronics: Used for connector housings, terminal blocks, and shielding components due to high dimensional accuracy and good electrical properties.
Hardware: Common in locks, gears, and fasteners where strength and detail are essential.
Consumer Products: Frequently used in door handles, bathroom accessories, furniture hardware, and decorative trim, thanks to its smooth finish and easy plating.
Aluminum Die Casting Applications
Automotive: Extensively used in parts like transmission housings, engine blocks, and brackets, contributing to better fuel efficiency and vehicle performance.
Aerospace: Found in lightweight structural parts such as housings, radiators, hinges, and mounts.
Electronics: Commonly used for LED light housings, power tool casings, and heat sinks due to its excellent thermal performance.
CEX Casting Capabilities
CEX Casting is a professional zinc & aluminum die casting manufacturer in China with 29 years of experience.
We provide end-to-end custom die casting services, from mold design and development to die casting and final finishing.
Our facility features five fully automated production lines combined with a centralized smelting system, ensuring consistent product quality.
We maintain a fully equipped in-house quality inspection lab with CMM, spectrometer, X-ray machine, tensile tester, and hardness tester.
Every product can be delivered with a detailed quality inspection report based on your requirements.
Conclusion
Zinc and aluminum die casting each offer unique advantages.
Zinc die casting is better for tight tolerances, fine details, and small parts, while aluminum die casting is ideal for structural strength, thermal resistance, and corrosion protection.
The best material depends on the application, performance goals, and budget.
As a reliable aluminum and zinc alloy die casting supplier, CEX Casting offers one-stop solutions from mold to finished product.
Contact us today for tailored advice and expert support for your next die casting project.