Views: 22 Author: Site Editor Publish Time: 2021-03-29 Origin: Site
Introduction Of Thermal Interface Material And Its Application An LED Lamps
1. What is a materials ofthermal conductive interface
• A materials of thermal conductive interface, also known as thermal interface material or interface thermally conductive material, is a material commonly used for IC packaging and electronic heat dissipation. It is mainly used to fill the micro-voids and uneven surface holes generated when two materials are joined or contacted. , Reduce the thermal contact resistance of heat transfer and improve the heat dissipation performance of the device.
• Thermal interface (contact surface) materials play a very critical role in thermal management and are an important research branch in this discipline.
2. Why do we need thermal interface materials
• There is a very small uneven gap between the surface of the microelectronic material and the heat sink. If they are directly installed together, the actual contact area between them is only 10% of the base area of the heat sink, and the rest are air gaps. Because the air thermal conductivity is only 0.024W/(m·K), it is a poor conductor of heat, which will result in a very large contact thermal resistance between the electronic components and the radiator, which will seriously hinder the heat conduction and ultimately cause the efficiency of the radiator to be low. .
• Use a thermal interface material with high thermal conductivity to fill these gaps, eliminate the air in them, and establish an effective heat conduction channel between the electronic components and the radiator, which can greatly reduce the contact thermal resistance, so that the role of the radiator can be fully exerted .
3. What is the ideal thermal interface material?
• The characteristics of an ideal thermal interface material are:
•(1) High thermal conductivity;
• (2) High flexibility, to ensure that the thermal interface material can fully fill the gaps on the contact surface under the condition of lower installation pressure, and to ensure that the contact thermal resistance between the thermal interface material and the contact surface is small; (3) Insulation ；
•(4) Easy to install and detachable;
• (5) Wide applicability, can be used to fill small gaps as well as large gaps.
Fourth, the introduction of several common thermal interface materials
• 1. Thermally conductive silicone grease
• (1) Thermally conductive silicone grease is commonly known as thermal grease. The thermally conductive silicone grease is made of silicone as the main raw material and added with heat-resistant and thermally excellent materials to make a thermally conductive silicone grease-like compound.
• (2) Advantages: High cost performance, the most common thermal conductive material in electronic heat dissipation.
Note: The operation is inconvenient. The general thermal paste will have silicone oil precipitated, and it will dry after a long time. It is not recommended to use the thermal paste for products with a long service life.
2. Thermally conductive silicone sheet
A. Thermally conductive silicone sheet is a kind of thermally conductive medium material synthesized by special process with silica gel as the base material and various auxiliary materials such as metal oxides.
B. In the industry, it is also known as thermally conductive silicone pad, thermally conductive silicon film, soft thermally conductive pad, etc. It is specially produced for the design of using the gap to transfer heat, which can fill the gap and complete the heat transfer between the heating part and the heat dissipation part. .
C. At the same time, it also plays the role of insulation, shock absorption, sealing, etc., which can meet the design requirements of equipment miniaturization and ultra-thinness. It is extremely manufacturable and usable, and has a wide range of thicknesses. It is an excellent thermal conductivity Filler.
Advantages of thermally conductive silicone sheet
•1) The range and stability of the thermal conductivity of the thermally conductive silicone sheet
•2) The thermal conductive silicone sheet bridges the process gap in the structure and reduces the process gap requirements of the radiator and the heat dissipation structure
•3) Thermally conductive silicone sheet has insulating properties.
•4) Thermally conductive silicone sheet has the effect of shock absorption and sound absorption.
•5) The thermal conductive silicone sheet has the convenience of installation, testing, and reusability.
Thermally conductive phase change material
•Phase Change Material (PCM-Phase Change Material) refers to a substance that changes shape with temperature changes and can provide latent heat. The process of phase change material from solid to liquid or from liquid to solid is called phase change process. At this time, the phase change material will absorb or release a large amount of latent heat.
•Advantages: The phase change material is now mainly solid-solid phase change. In the face of thermal shock, it can absorb a certain amount of heat through the phase change and slow the impact of large heat flux. It is like adding a water storage to the heat conduction channel Pool. The phase change temperature of the current phase change materials on the market is about 45 ℃-50 ℃. The phase change materials are mainly used in heat sources with instantaneous large heat fluxes such as CPUs, which can play a good protective role. , Especially at the moment of booting or restarting. Note: There is a certain heat capacity and thermal resistance less than the thickness of the thermally conductive silicone sheet, which can be 0.125mm. It is not easy to store and install, and silicone oil will precipitate, which will affect the light effect of the lighting equipment. Changing the thermal conductivity medium is more suitable for consumer electronics and other products, especially notebook computers, game consoles, etc. However, its reliability is not good, and its performance will decline under high temperature for a long time. Generally used for 2 years, the performance will drop by about 40%-- -70%.
In summary.thermal conductive interface directly affects the quality of the thermal interface.