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Phase Change: How to Select Phase Change Materials
Release time:
2021-08-05
Phase Change: How to Choose Phase Change Materials
Phase Change: Phase-change thermal conductive materials are a type of heat-enhanced polymer mainly used to reduce the thermal resistance between power-consuming electronic devices and their connected heat sinks to a very low level. This low thermal resistance path allows the heat sink to perform well, enabling better operation of microprocessors, storage modules, DC/DC converters, and power modules.
Phase Change: How to Choose Phase Change Materials
(1) Phase Change - Thermophysical Properties: Specifically, the phase change temperature should remain moderate, the phase change enthalpy should be as large as possible, and the heat transfer characteristics should be as good as possible. When determining the appropriate phase change material to fill the thermal storage system, the operating temperature of the heating and cooling system must meet the phase change point of the phase change material. In addition, it should be noted that the higher the phase change enthalpy of the selected material, the better, especially the higher the phase change enthalpy per unit volume, which can save container volume. In addition, the thermal conductivity of the selected phase change material should be as high as possible, which can help the thermal storage system store heat.
(2) Phase Change - Physical Factors: Including good phase equilibrium, high density, small volume change, and low vapor pressure. Phase stability during heating and melting helps store heat; high density allows for smaller container design; lower vapor pressure and smaller volume change help reduce container airtightness.
(3) Kinetic Factors: Including no supercooling and sufficient crystallization. Supercooling is a major drawback of some phase change materials, especially for hydrated salts, and is a problem that needs to be addressed first. This is because supercooling can severely weaken the latent heat value of the phase change material, even with an increasing number of cycles. The degree of supercooling can cause the thermal storage material to completely lose its ability to store and release heat.
(4) Phase Change - Chemical Factors: Including the chemical stability of the material should be maintained for as long as possible; the thermal storage material should have good compatibility with the container material; the material should be non-toxic and non-flammable.
(5) Phase Change - Economic Factors: Including abundant sources, easy availability, and low Price. In order for phase change materials to have industrial application value, their Price should be as low as possible without significantly increasing industrial costs.
Phase Change: Thermally Conductive Phase Change Material
Phase Change: The main performance of thermally conductive phase change materials is its phase change properties: it is a solid at room temperature and easy to handle, so it can be used as a dry pad and pasted on the surface of the heat sink or device. When the working temperature of the device is reached, the phase change material softens, and with a slight tightening force, the material can easily integrate with the two mating surfaces like hot grease. The ability to completely fill the gaps between interfaces and between the device and the heat sink makes the phase change pad superior to non-flowing elastomers or graphite-based thermal pads, and achieves performance similar to thermal grease.
Phase Change: How to Use Thermally Conductive Phase Change Materials
Step 1: Clean the surface of the heat sink with a lint-free cotton ball (cotton cloth) using an alcohol or isopropyl alcohol solvent.
Step 2: Peel off the transparent protective film on the thermally conductive phase change pad and stick it to the heat sink.
Step 3: Gently press the thermal pad on the thermally conductive phase change pad with your fingers.
Step 4: Tear off the blue protective film on the thermally conductive phase change pad by hand and press the device on top.
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