In the field of electronic equipment and technology, thermal silicone sheets play a crucial role as an important thermally conductive material. Their design concept aims to provide more efficient heat conduction solutions, especially between electronic components that need to dissipate heat quickly and effectively. With the development of electronic equipment towards miniaturization and high performance, the performance requirements for thermal silicone sheets are also increasing day by day. This paper will deeply explore the main indicators of thermal silicone sheets and provide rich and comprehensive information and perspectives.
1. Thermal Conductivity
Thermal conductivity is a key indicator to measure the heat conduction capacity of thermal silicone sheets. The higher the thermal conductivity, the better the thermal conductivity of the material. In practical applications, it is usually desirable for thermal silicone sheets to have high thermal conductivity to effectively reduce the operating temperature of electronic equipment. The unit of thermal conductivity is W/m.K, and the thermal conductivity of common thermal silicone sheets ranges from 1.0 W/m.K to 10.0 W/m.K. The specific selection needs to be balanced according to actual requirements.
Thermal conductivity is usually measured by the laser flash method or the hot wire method. The former heats the surface of the material with a laser pulse and measures the temperature response; the latter heats the probe with constant power and measures the temperature rise. Regardless of the method, accurate measurement of thermal conductivity is crucial for the performance evaluation of materials.
2. Hardness
Hardness is one of the important physical performance indicators of thermal silicone sheets, which directly affects their application scenarios and installation convenience. Hardness is generally measured with a Shore durometer, and the common range is between 20 Shore C and 60 Shore C. Materials with excessively high hardness may exert pressure on electronic components during installation, and even damage the components; while materials with excessively low hardness may not provide sufficient mechanical support.
In practical applications, it is necessary to select thermal silicone sheets with appropriate hardness according to specific application environments and requirements. For example, in occasions requiring strong support force, materials with higher hardness are suitable; in occasions requiring better fit, materials with lower hardness should be selected to ensure good contact and thermal conductivity.
3. Thickness
Thickness is also an important factor affecting the performance of thermal silicone sheets. Thermal silicone sheets of different thicknesses are suitable for different application scenarios. Generally speaking, the thinner the thickness, the better the heat dissipation effect, because the thermal resistance is smaller, but it may be difficult to fill large gaps; the thicker the thickness, the better the filling performance, but it may lead to increased thermal resistance.
The selection of thickness needs to comprehensively consider factors such as the structural design of the equipment, component gaps, and thermal management requirements. Usually, the thickness range of thermal silicone sheets is between 0.5 mm and 20 mm, and the specific selection should be adjusted based on actual application needs.
4. Temperature Resistance
Temperature resistance is one of the important performance indicators of thermal silicone sheets, which determines the stability and reliability of the material in high-temperature environments. Thermal silicone sheets usually need to maintain good thermal conductivity and mechanical properties within a wide temperature range. The temperature resistance range of common thermal silicone sheets is -40℃ to 200℃, and some special applications may require higher temperature resistance.
Temperature resistance is usually measured by Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). TGA is used to measure the mass change of materials at different temperatures to evaluate their thermal stability; DSC is used to measure the heat flow change of materials at different temperatures to evaluate their thermal characteristics.
5. Breakdown Voltage
Breakdown voltage is an important indicator to measure the electrical insulation performance of thermal silicone sheets, especially in applications requiring electrical isolation. The higher the breakdown voltage, the better the electrical insulation performance of the material. Usually, the breakdown voltage range of thermal silicone sheets is between 4 kV/mm and 20 kV/mm.
Breakdown voltage is usually measured by high-voltage test equipment, recording the voltage value when the material undergoes electrical breakdown during the process of gradually increasing the voltage. This indicator is of great significance for ensuring the safe operation of electronic equipment.
6. Compression Deformation
Compression deformation refers to the degree of deformation of the thermal silicone sheet under pressure. This indicator affects the fit performance and service life of the material. Materials with excessively high compression deformation may lose elasticity during long-term use, affecting the heat dissipation effect; materials with excessively low compression deformation may not effectively fill gaps under pressure.
Compression deformation is usually measured by a compression test, measuring the thickness change of the material under a certain pressure and temperature. The common range of compression deformation is between 5% and 30%, and the specific selection should be adjusted according to application requirements.
7. Aging Resistance
Aging resistance refers to the degree of performance change of the thermal silicone sheet during long-term use. Excellent aging resistance can ensure that the material maintains stable thermal conductivity and mechanical properties during long-term use. The evaluation of aging resistance is usually carried out through accelerated aging tests, measuring the performance change of materials under conditions such as high temperature and high humidity.
The quality of aging resistance directly affects the service life and reliability of thermal silicone sheets, and is one of the key factors to consider when selecting materials.
8. Flame Retardancy
Flame retardancy is an important safety performance indicator of thermal silicone sheets in high-temperature or fire environments. Materials with good flame retardancy can effectively prevent the spread of flames and improve the safety of equipment. Flame retardancy is usually measured according to the UL 94 standard, and common grades include V-0, V-1, V-2, etc.
The improvement of flame retardancy is usually achieved by adding flame retardants, but it should be noted that flame retardants may affect the thermal conductivity and mechanical properties of the material, so comprehensive trade-offs are required in practical applications.
9. Volume Resistivity
Volume resistivity is another important indicator to measure the electrical insulation performance of thermal silicone sheets. The higher the volume resistivity, the better the electrical insulation performance of the material, especially in applications requiring prevention of current leakage. The volume resistivity range of common thermal silicone sheets is above 10^14 Ω·cm.
Volume resistivity is usually measured by resistivity test equipment, recording the resistance value of the material under a certain voltage. High volume resistivity can effectively prevent electrical faults and ensure the safe operation of electronic equipment.
As an indispensable thermally conductive material in electronic equipment, the performance indicators of thermal silicone sheets directly affect the heat dissipation effect and safety of the equipment. By deeply exploring the main indicators such as thermal conductivity, hardness, thickness, temperature resistance, breakdown voltage, compression deformation, aging resistance, flame retardancy and volume resistivity, we can more comprehensively understand and select thermal silicone sheets suitable for different application requirements. In practical applications, it is necessary to comprehensively consider various performance indicators according to specific equipment and service environments, and select the best thermal silicone sheet to ensure the stable operation and long service life of the equipment.
With the continuous progress of technology and the diversification of application requirements, the performance requirements for thermal silicone sheets are also constantly improving. In the future, thermal silicone sheets will develop towards higher thermal conductivity, better mechanical properties, stronger electrical insulation and longer durability, providing more reliable solutions for the thermal management of electronic equipment.
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Written by
CoolingThermal Engineering TeamCoolingThermal is an automation equipment manufacturer based in Kunshan, China, specializing in heat pipe and vapor chamber production equipment since 2017. Our engineering team designs, builds, and commissions complete production lines covering forming, degassing, welding, testing, and assembly processes. The technical content on this blog is written by the same team that develops the equipment — based on real production experience, not secondary research.
