Some electronic products are easy to get hot during use, resulting in slow
operation or direct burnout of the motherboard. Disassemble and inspect and
found that the surface of the thermally conductive silicone grease appears dry
and cracked, indicating that the service life of the electronic products and
the thermally conductive silicone grease are large relationship. What is the
situation of cracking during the application of thermal grease, and what are
the reasons?
1. Uneven
After the oil powder is separated from the thermal conductive silicone
grease, the stirring is uneven before use, which leads to the phenomenon that
the thermal conductive silicone grease has more powder and less oil locally
during the printing and smearing process. It is difficult to lock the oil as a
whole, and a small amount of oil is slowly precipitated after a certain period
of time, causing the colloid to pulverize and form cracks.
2. Raw materials
The choice of silicone oil has a very important impact on the service life
and performance of thermally conductive silicone grease. Silicone oil is a
polymer material, but in the synthesis process, it will be mixed with low
molecules. If the low molecules are not treated well to remove, it will exist
in the polymer silicone oil products, and then used in the production of
thermal conductive silicone grease. The thermal conductive silicone grease with
low molecular content and high content is easy to volatilize at high
temperature. The volatilization process of small molecules causes the colloid
to expand, and the colloid will crack in severe cases.
3. Oil separation rate
The oil separation rate of thermal grease is a measure of the long-term
performance of the product. Thermal grease with different formulations and
production processes has different oil separation rates. The greater the oil
separation rate of thermal grease, the shorter the normal use time. The reason
is that the thermal conductive silicone grease with high oil separation rate,
the silicone oil is relatively easy to seep out, separate from the powder, and
the powder lacks the mixing of oil, which will dry out, and cracks will also
appear after serious drying. Therefore, the smaller the oil separation rate,
the better, and the less likely it is to crack.
No matter what the reason is for the thermal conductive grease to crack
during the application process, it will directly reduce the thermal
conductivity. However, whether the thermal conductive silicone grease you use
will crack in a short period of time cannot be directly distinguished from the
appearance or from the It is directly identified in operation, so it is
necessary for users to understand the prevention and verification method of
cracking during the application of thermal grease.
