How Heat Sink Compound Keeps Electronics Cool

What is heat sink compound?

Heat sink compound is a sticky paste that is used as an interface between CPU heat sinks and heat sources.

What is the purpose of heat sink compounds?

Heat sink compound is used to bridge any spaces between the CPU (central processing unit) or other heat-producing elements and the physical heat sink. This heat sink, constructed from conductive metal, is passively positioned above the CPU. Heat is transferred from the CPU to the heat sink, which then disperses it through its fins, allowing a fan to blow air through and dissipate the excess heat.

Thermal transfer inefficiencies arise from the imperfect alignment of two flat surfaces, such as the CPU and the mechanical heat sink, which never achieve perfect contact. Consequently, an air gap forms due to surface imperfections. Since air is a poor thermal conductor, this gap can hinder heat dissipation, leading to device overheating and failure.

Heat sink compound is applied to bridge this gap, facilitating efficient heat transfer from the heat-generating component to the heat-dissipating device. Although the compound may not match the thermal conductivity of metals like copper and silver, its conductivity surpasses that of air, enhancing thermal responsiveness.

Material Thermal Conductivity (W/mK)
Air 0.026
Heat Sink Compound 0.5-1.0
Aluminium 220
Copper 390
Silver 420

Note: Conductivity may vary depending on the material type. Measurements taken at room temperature

Techspray Heat Sink Compound

Techspray provides two variations of heat sink compound: silicone (part #1977-DP) and silicone-free (part #1978-DP and #1978-1). The silicone heat sink compound represents an older formulation, more suitable for electrical applications. It combines silicone with zinc oxide to form a paste that is easy to apply but does not spread unintentionally.

However, silicone oil within the compound can migrate, potentially causing issues with solderability and dewetting of the conformal coating. Techspray's Silicone-Free Heat Sink Compound eliminates silicone migration while offering similar application properties and thermal conductivity. Both products effectively enhance thermal transfer efficiency and help prevent overheating.

For further details on heat sink compounds, please reach out to our team at 

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