Thermally conductive silicone sheet, as a high-performance thermally conductive interface material, exhibits a significant impact on thermal conductivity due to its compression deformation characteristics. This impact stems from the physical changes in the material under pressure and how these changes alter the efficiency of the heat conduction path. From a materials science perspective, the compression deformation of a thermally conductive silicone sheet refers to the process of thickness reduction and volume shrinkage under pressure. This process is directly related to the adhesion between the material and the contact surface and changes in thermal resistance.
When a thermally conductive silicone sheet is compressed, its internal structure adjusts. The originally loose silicone matrix becomes denser under pressure, and the contact between the thermally conductive filler particles becomes tighter, forming more efficient heat conduction channels. This structural change allows heat to be transferred through the material more quickly, thereby reducing contact thermal resistance. For example, in electronic device heat dissipation scenarios, the compressed thermally conductive silicone sheet can better fill the tiny gaps between the CPU and the heatsink, reducing air thermal resistance and significantly improving heat dissipation efficiency.
The positive impact of compression deformation on thermal conductivity is also reflected in improved material adaptability. Thermally conductive silicone sheets possess excellent flexibility and compressibility, allowing them to adapt to various complex shapes and uneven surfaces. When compressed, they adhere more tightly to the contact surface, eliminating gaps caused by surface unevenness and ensuring unobstructed heat transfer paths. This seamless fit not only improves heat conduction efficiency but also reduces energy loss during heat transfer, ensuring that every unit of heat is effectively utilized.
However, greater compression deformation is not always better. Excessive compression can lead to decreased performance or material damage to the thermally conductive silicone sheet. When the compression ratio exceeds the material's limits, irreversible plastic deformation may occur in the silicone matrix, causing the bonds between the thermally conductive filler particles to break and disrupting the heat conduction channels. Furthermore, excessive compression can cause stress concentration within the material, leading to cracks or breakage, further reducing thermal conductivity. Therefore, in practical applications, an appropriate compression ratio must be selected based on the specific scenario to balance thermal conductivity and material lifespan.
The hardness of the thermally conductive silicone sheet also affects the relationship between its compression deformation and thermal conductivity. Generally, thermally conductive silicone sheets with lower hardness have better compressibility, making them more adaptable to various shapes and gaps, thus providing better thermal conductivity. However, excessively low hardness can also cause deformation during use, affecting heat dissipation performance. For example, in high-temperature environments, an overly soft thermally conductive silicone sheet may compress further due to thermal expansion, leading to excessive contact surface pressure and increasing thermal resistance. Therefore, when selecting thermally conductive silicone sheets, the relationship between hardness, compressibility, and thermal conductivity must be comprehensively considered.
In practical applications, the compression deformation characteristics of thermally conductive silicone sheets are also affected by various factors such as assembly pressure and operating temperature. The magnitude of assembly pressure directly affects the material's compressibility, while operating temperature may change the material's elastic modulus, thus affecting its compression recovery ability. Therefore, when designing heat dissipation schemes, these factors must be fully considered, and the optimal compressibility range should be determined experimentally to ensure that the thermally conductive silicone sheet maintains stable thermal conductivity during long-term use.
The compression deformation of thermally conductive silicone sheets has a dual impact on thermal conductivity. Moderate compression can improve the fit between the material and the contact surface, reduce thermal resistance, and significantly improve heat dissipation efficiency; however, excessive compression may lead to a decline or damage to material properties, thus reducing thermal conductivity. Therefore, in practical applications, it is necessary to select appropriate compression ratios, hardness, and assembly pressures according to the specific scenario to achieve the best heat dissipation effect.
