A thermal paste (also called thermal grease or thermal compound) is a substance that increases the thermal conductivity between two surfaces. They are mainly used in electronics, where thermal pastes maximise heat dissipation from the heated object (CPU or GPU) and a heat sink through
CPU Coolers.
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Thermal pastes are therefore primarily used for better heat transfer away from CPUs or graphics cards.
How do Thermal Pastes Work?
Thermal pastes fill small, microscopic surface irregularities between the contact surfaces, such as air gaps or spaces which act as insulators. The heat sink then dissipates the heat. When the appropriate amount of thermal paste is applied, the thermal paste fills in the unevenness between the two surfaces, improves the contact area between the two objects and works as a heat conductor.
How Do You Choose Thermal Paste?
The most important parameter is thermal conductivity, which depends on the composition of the liquid component of the thermal paste. The main purpose is to eliminate air pockets between the two surfaces which contribute to poor thermal conductivity.
Basic Types of Thermal Pastes:
- Silicone-based
- Ceramic-based
- Metal-based
Silicone Thermal Pastes
- Medium thermal conductivity
- Usually supplied together with a CPU cooler
Ceramic Thermal Pastes
- High thermal conductivity (but worse than metal-based thermal pastes)
- Suspension of ceramic particles with other thermally conductive substances
Metallic Thermal Pastes
- Best thermal conductivity
- It contains metal particles (silver)
- The disadvantages are a higher price and electrical conductivity
