Thermal Greases
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About thermal conductivity pastes
Thermal grease is used in electrical engineering and computer components to dissipate heat quickly and thus prevent damage due to overheating . . In this respect, it is part of passive cooling technology for heat dissipation on active components such as semiconductors, sensors and opto-electronic components.
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How does heat transfer compound work?
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What is the thermal grease used for?
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What was to be taken into account when selecting heat transfer compound?
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How is heat conductive paste applied?
How does heat transfer compound work?
Background knowledge: Due to the increasing miniaturization of electrical components, the safe removal of heat is becoming increasingly difficult, although this amount of heat is now increasing as the electronics become more powerful. This problem is compounded by manufacturers' failure to install active fans to reduce material and energy consumption and reduce noise. In order to avoid heat accumulation, the use of heat conductive pastes, adhesives, films and heat conductive pads is indispensable.
Thermal pastes are used to improve thermal connections. They are partly viscous or at least viscous . Some heat conductive pastes are electrically conductive, others are not.
Heat transfer compound is applied between the component and its heat sink or corresponding heat transfer pipes or foils for heat transfer.
In order to optimize the heat transfer, heat transfer paste fills small cavities between the contact surfaces at the connection point. It displaces the trapped air and forms a heat-conducting layer between the components . Heat is dissipated much more efficiently with heat conductive paste than without. This allows you to significantly expand the cooling reserves of your system.
Note: Thermal grease does not adhere sufficiently to establish a firm connection between components not otherwise fixed. Thermal adhesive can be found here.
What is the thermal grease used for?
An intermediate layer of heat conductive paste optimizes the heat transfer between electronic components and their cooling elements. This allows heat generated during the operation of the active components to be removed more quickly. This reduces the risk that sensitive components, such as LED lights, sensors, processors and other semiconductor elements, will suffer premature wear due to excessive temperatures.
High-performance heat conductive paste is used as heat conductor for CPU coolers.
What was to be taken into account when selecting heat transfer compound?
Thermal conductivity & maximum temperature
The efficiency of heat conductive paste depends on the respective thermal conductivity capability of a product offered.
The so-called heat conductivity coefficient as an indicator for thermal conductivity is given in W/MK. This unit covers the power of heat output in watts, per distance in meters and temperature difference in Kelvin. 1 Kelvin corresponds to 1° C.
Practical knowledge:
The higher the thermal conductivity , the better the thermal conductivity, so the faster a certain amount of heat can be dissipated .
A second important selection criterion is the maximum temperature that a heat conductive paste may be exposed to. Make sure that the maximum temperature values for the heat paste are never exceeded in practice. werden. If the maximum temperature at the connection point with the applied heat conductive paste is exceeded during operation, this can lead to irreversible changes in the structure of the paste. As a result, a loss of thermal conductivity can be expected, and the components that you wanted to protect threaten to overheat without hindrance.
Other properties
Most thermal conductive pastes are not electrically conductive, while liquid metal heat conductive pastes are. The choice based on electrical conductivity or insulation plays a major role in hardware of electrical applications in order to prevent unwanted current transfers at the layer of heat transfer compound.
The color of heat conductive paste sometimes plays a role in visible applications.
Pack size & application aids
Thermal grease is often offered in small units with a few grams or milliliters of content . Similar to solder paste, this is sufficient for some small connection points. However, if you handle with heat conductive paste in a large style, you better immediately reach a more extensive filling quantity of 100 to 500 grams or order several small fillings and receive the quantity discounts shown in the shop.
Note: Heat transfer compound must be used as soon as possible after the packaging has been broken.
For precise application of the heat conductive paste, spray tubes are suitable, which are often offered as packaging for the heat conductive paste. For larger contact surfaces, which are to be coated with heat conductive paste, putty is used.
How is heat conductive paste applied?
If you have selected the correct heat transfer compound based
on the relevant product characteristics and if the required package size is ready for use, proceed as follows: Always read the enclosed leaflet first and observe the manufacturer's instructions.
The application of heat conductive paste is usually very easy in three steps:
- Before applying heat transfer compound, disconnect all components from the power supply.
- Heat conductive paste should be applied precisely because:
- If the heat conductive paste is too low, the good thermal conductivity between the contact surfaces is not guaranteed and there may be threatening heat build-up at the connection point.
- If the heat transfer compound is too high, the path that the heat must travel before it is dissipated will be extended. This will cause a delay and possibly lower cooling performance.
- Always allow the heat conductive paste to harden sufficiently before you undergo a first practical test
If components connected to heat transfer compound are disconnected again later , you should carefully scrape off the remains of the old paste, if possible. For a new connection to the old contact surfaces, you always need fresh heat conductive paste, because only in this way the air pockets at the connection point are displaced, which was the prerequisite for a good thermal conductivity.