Why is Aluminum Used for Heat Sinks? — The Ultimate Guide
Material comparisons, common alloys, extrusion & manufacturing, and practical FAQ for designers, buyers, and engineers.
Introduction
Heat sinks transfer heat away from components into the surrounding air. People often ask whether aluminum, copper, or ceramic is best, which alloys are used for large extrusions, and how aluminum heat sinks are manufactured. This guide covers those questions plus practical application notes and a helpful FAQ.
1. Why Aluminum is Used for Heat Sinks
- Thermal conductivity: ~200 W/m·K — sufficient for most applications.
- Lightweight: approx. one-third the density of copper.
- Cost-effective: lower material & machining cost vs copper.
- Manufacturability: ideal for extrusion into complex fin profiles.
- Corrosion resistance: natural oxide plus anodizing options.
2. Aluminum vs. Copper vs. Ceramic
| Material | Thermal Conductivity | Weight | Cost | Manufacturability | Typical Applications |
|---|---|---|---|---|---|
| Aluminum | ~200 W/m·K | Light (~1/3 of copper) | Low — most cost-effective | Excellent — easy extrusion & machining | LED, power supplies, consumer electronics |
| Copper | ~400 W/m·K | Heavy | High — expensive | Challenging — harder to extrude, higher machining cost | High-performance CPUs, servers, power modules |
| Ceramic | ~20–30 W/m·K (varies) | Medium | Moderate–High | Limited — brittle, limited size | Insulated power electronics, high-temp components |
Summary: Aluminum provides the best balance of performance, manufacturability and cost for most heat sink applications. Copper is chosen for peak thermal performance; ceramic when electrical insulation is required.
3. Aluminum Alloys for Heat Sinks (Common Choices)
| Alloy / Material | Thermal Conductivity | Mechanical Strength | Corrosion Resistance | Manufacturability | Typical Use |
|---|---|---|---|---|---|
| 6063-T5 / T6 | Good (★ ★ ★ ☆) | Medium (★ ★ ☆) | Excellent (★ ★ ★ ★) | Best for extrusion (★ ★ ★ ★) | Standard extruded heat sinks |
| 6061-T6 | Medium (★ ★ ☆) | High (★ ★ ★ ★) | Good (★ ★ ★) | Harder to extrude (★ ★ ★) | When strength & structure matter |
| Pure Al (1050 / 1100) | Excellent (★ ★ ★ ★) | Low (★) | Good (★ ★ ★) | Poor for extrusion (★) | Specialty, limited use |
In practice, 6063-T5/T6 is the industry standard for large extruded heat sinks; 6061 is used when additional structural strength is required.
4. How Aluminum Heat Sinks Are Made
Most commonly by aluminum extrusion. Typical workflow:
- Billet preparation: preheat aluminum logs.
- Extrusion: force billet through a die to form finned profiles.
- Cutting: cut profiles to required lengths.
- Machining: CNC drilling, tapping, slots.
- Surface finish: anodize or powder-coat for protection and appearance.
Other manufacturing methods: die-casting (complex shapes), bonded/skived fins (high surface area thin fins).
5. FAQ — Quick Answers to Common Customer Searches
6. Typical Applications
Aluminum heat sinks are widely used across industries:
- LED lighting systems
- Power supplies & inverters
- Industrial automation & controllers
- Communication equipment
- Automotive electronics
- Consumer electronics — PCs, laptops, single-board computers
Conclusion
Aluminum is the industry standard for heat sinks due to its balance of thermal performance, manufacturability and cost. For most LED, power and consumer electronics applications, 6063 extruded aluminum heat sinks deliver the best overall value. Use copper only where top-tier thermal conductivity is essential, and ceramic when electrical insulation is required.
