Thermal Gel vs Thermal Paste: Key Differences Explained

What Is Thermal Paste?

Thermal paste, also known as thermal grease or heat transfer paste, is a viscous material designed for thin-gap applications. With a thermal conductivity range of 1.0 to 5.0 W/m·K, it is primarily composed of silicone oil and thermally conductive fillers. Thermal paste has low thermal resistance and excellent wetting properties, allowing it to fill microscopic gaps effectively.

Key Features of Thermal Paste:

• Non-Curing: Thermal paste remains in its original state and does not harden, making it easy to reapply.
• Thin Application: Minimum interface thickness of 0.02mm, making it ideal for thin-gap applications.
• Customizable Viscosity: Can be adjusted according to specific customer requirements.
• Applications: Best suited for thin-gap applications like CPUs, GPUs, and other high-performance computing devices. It can be applied manually or via screen printing without the need for preheating.

What Is Thermal Gel?

Thermal gel, also referred to as thermal putty or liquid thermal gap filler, is a versatile material available in various formulations, such as single-component silicone gel, dual-component silicone gel, and silicone-free gel. Thermal gels are known for their adaptability to large-gap applications and their excellent thermal conductivity, ranging from 1.0 to 10.0 W/m·K.

Types of Thermal Gel:

1. Single-Component Thermal Gel (SE Series):

   • Thermal Conductivity: 1.0 to 10.0 W/m·K
   • Features: Non-curing, low thermal resistance, good wetting and thixotropic properties, and low assembly stress.
   • Applications: Ideal for filling thin gaps with large tolerance variations in automotive electronics, smartphones, laptops, and communication devices.

2. Dua-Component Thermal Gel (SE Series AB):l

   • Thermal Conductivity: 1.0 to 8.0 W/m·K
   • Features: Cures at room temperature, becomes an elastic solid after curing, offers low thermal resistance, and provides cushioning and shock absorption.
   • Applications: Suitable for automated dispensing machines and applications requiring durable thermal connections.

3. Silicone-Free Thermal Gel (AE Series):

   • Thermal Conductivity: 1.0 to 3.0 W/m·K
   • Features: Non-curing, free of silicone oil migration and siloxane volatility, suitable for silicone-sensitive environments.
   • Applications: Designed for filling thin gaps in silicone-sensitive scenarios, using automated dispensing machines.

Key Differences Between Thermal Gel and Thermal Paste

1. Thermal Conductivity:

   • Thermal paste typically has a conductivity of 1.0 to 5.0 W/m·K, suitable for thin-gap applications.
   • Thermal gel offers a wider range of 1.0 to 10.0 W/m·K, making it more versatile for varying gap sizes.

2. Application and Reworkability:

   • Thermal paste is non-curing and ideal for thin, precise applications.
   • Thermal gel, particularly non-curing types, adapts to larger gaps and remains flexible, making it easier to rework.

3. Durability:

   • Dual-component thermal gels cure into an elastic solid, providing better structural stability and shock absorption compared to thermal paste.

4. Use Cases:

   • Thermal paste excels in high-performance computing environments like CPUs and GPUs.
   • Thermal gel is more suited for applications with larger gaps or variable tolerances, such as automotive electronics and telecommunication devices.

Which One Should You Choose?

• Choose Thermal Paste: For applications requiring thin-gap filling, such as CPUs and GPUs, where low thermal resistance and precise application are crucial.
• Choose Thermal Gel: For applications with larger gaps, silicone-sensitive environments, or where reworkability and durability are required.