Exploring Thermal Conductive Interface Materials: Types, Characteristics and Applications

Exploring Thermal Conductive Interface Materials: Types, Characteristics and Applications

Today, with the miniaturization and high performance of electronic equipment, the power of heating components such as chips is constantly improving, and the heat dissipation problem has become a key factor affecting the stability and service life of equipment. Thermal Interface Materials (TIM), as a "bridge" connecting heat source and radiator, can effectively fill tiny gaps between interfaces, reduce thermal resistance and improve heat dissipation efficiency. Next, let's deeply understand the main types and characteristics of thermal interface materials.

Thermal grease

Thermal conductive silicone grease, also known as heat dissipation paste, is a common paste-like thermal conductive interface material. It is made of silicone resin as matrix and high thermal conductivity filler (such as alumina, aluminum nitride, zinc oxide, etc.). Its advantage lies in its good fluidity and wettability, which can fully fill the tiny gap between the heat source and the radiator and effectively reduce the contact thermal resistance. The thermal conductivity of thermal conductive silicone grease is generally between 1-15w/(MK), which is suitable for the heat transfer between the heat sink and chips with high heat dissipation requirements such as CPU and GPU. ​ However, thermal conductive silicone grease also has some limitations. It has no structural support capacity, and the coating thickness needs to be strictly controlled. Too thick or too thin will affect the heat dissipation effect. Moreover, in the process of long-term use, silicone grease may dry up and its performance may decrease, so it needs to be replaced regularly.

Thermal pad

Thermal pad is a kind of sheet-like thermal conductive material with certain flexibility and elasticity, which is usually composed of polymer matrix (such as silicone rubber, polyurethane, etc.) and thermal conductive filler. According to the different hardness and shape, heat-conducting gasket can be divided into non-silicon heat-conducting gasket, high-hardness heat-conducting gasket, self-adhesive heat-conducting gasket and many other types. ​ The thermal conductivity of the thermal conductive pad is wide, generally 1-12w/(MK), which can closely adhere to the heating surface and the heat dissipation surface under a certain pressure and play a good role in buffering and damping. It is suitable for electronic components that are sensitive to mechanical stress, such as cooling modules in tablet computers and notebook computers. Because of its convenient installation, no complicated coating process and long service life, it has gradually become one of the mainstream options for heat dissipation of electronic equipment.

Thermal conductive gel

The thermal conductive gel has both the high filling property of thermal conductive silicone grease and the flexibility of thermal conductive gasket. It is based on silicone, with special thickener and high thermal conductivity filler. When it is not cured, it is gel-like, which can easily fill the interface gap and form an elastomer after curing. ​ The thermal conductivity of thermal conductive gel is usually 3-10w/(MK), which has the advantage that the dosage can be accurately controlled by dispensing process, and it has good aging resistance and mechanical stability after curing, and it will not dry up and crack, so it is suitable for automatic production. It is often used in mobile phones, smart wearable devices and other electronic products with strict requirements on space and heat dissipation.

Thermal conductive phase change material

Thermal conductive phase change material is a kind of special thermal conductive material with phase change in a certain temperature range, and the common phase change is from solid to liquid. In the process of phase change, materials can absorb or release a lot of latent heat, thus achieving efficient heat transfer. ​ This kind of material is solid at room temperature. When the temperature rises to the phase transition point, it will be transformed into a liquid with good fluidity to fill the interface gap, and its thermal conductivity will be significantly improved before and after the phase transition, generally reaching 5-15w/(MK). Thermal conductive phase change materials are especially suitable for electronic equipment with high heat dissipation requirements and large fluctuation of heating power, such as game books and servers.

Thermal conductivity potting

Thermal conductivity potting is a two-component or one-component liquid heat-conducting material, which is filled in the gap or cavity of electronic equipment by potting process and solidified to form a solid with certain strength and heat conductivity. It is mainly composed of resin matrix (such as epoxy resin, silicone resin, etc.) and heat conductive filler. ​ The Thermal conductivity potting compound is generally 1-8W/(MK), which can not only conduct heat, but also play the roles of waterproof, dustproof, insulation and mechanical fixation. It is often used in power modules, LED driving power supplies and other electronic devices that need integral sealing and heat dissipation.

With the rapid development of electronic technology, the requirements for thermal interface materials are getting higher and higher. In the future, thermal interface materials will develop in the direction of higher thermal conductivity, lower thermal resistance, thinner thickness, more environmental protection and multifunctional integration to meet the emerging new application scenarios and technical requirements.