Learning how to apply thermal grease

To learn how to apply thermal grease, you need only two things: a bit of free time and an Internet connection. In the global network, a lot of articles are devoted to this topic. They are written by everyone who is not too lazy - from venerable computer gurus to beginners, who want to assert themselves in this way. Especially in the question of how to apply thermal grease, there is nothing complicated. Even with insufficient accuracy nothing terrible will happen. Is that the temperature will be higher than it could be. Although, of course, if you smear such a paste on the motherboard, like butter on bread, then nothing good will come of it. Speaking of inaccuracy, we mean reasonable limits.

In most articles on how to apply thermal grease, only computer components are indicated. In fact, the field of application of this viscous substance is not limited only to computer technology. Among the elements of electronic circuits there are several, which are considerably heated during operation. The level of heating is so great that without the use of a relatively massive heat dissipating radiator they very quickly fail. These are some transistors, semiconductor diodes, integrated circuits.

Obviously, the denser the surfaces of the radiator and the cooled element touch, the more effective the heat sink. It follows that in order to increase the efficiency of heat dissipation, it is necessary to eliminate all surface treatment defects: they must be perfectly even, parallel, and the vector of pressing force would be an exact perpendicular. However, instead of performing such scrupulous work in production, a different solution is used. Between the surfaces a viscous mass is applied, due to fluidity, compensating for processing defects. In fact, we are talking about an intermediate thermal interface with a high coefficient of thermal conductivity. The best thermal grease should have the following properties:

- heat transfer is not worse than the radiator material;

- be liquid, but do not spread;

- Possess the ability to "stick" to surfaces.

It is easy to understand that manufacturers of thermal grease are compromising, trying to combine the opposite properties in the product. Very often the composition of pastes is kept secret, therefore it is difficult to verify the claims of producers. For example, the thermal paste Zalman, in which the base is zinc oxide, dissipates 1.2 W / m * K, but the Soviet KPT-8 is only 0.7 units. However, knowing how to apply the thermal paste correctly, it is possible to achieve quite acceptable efficiency of the heat sink.

To do this, you need to thoroughly clean the surface of the remnants of the previous thermal interface. Ideally suited dense fleecy fabric. Then, apply a paste to the surface of the heating element with a thin layer. Unfilled areas should not be, but surpluses will only worsen heat transfer (after all, even the best thermal paste conducts heat worse than metal). After this, you need to gently connect the surfaces and fix them with a clamping system. At the same time, distortions are inadmissible, since they reduce the area of contact and reduce efficiency.