Silicone greases are formulated to provide very durable, non-setting, work stable products used to lubricate, electrically insulate and act as a heat transfer medium. They provide excellent protection against moisture and other harsh environmental conditions. Silicone polymers in general exhibit good resistance and remain stable when operating in an environment with elevated temperatures and silicone greases are no exception.
CHT manufacture two types of silicone grease:
It is particularly important that the grease remains stable during storage and when in use. Some formulations may have the tendency to split or separate slightly allowing small amounts of silicone fluid to rise to the surface - these can normally be mixed back in without detrimental effects.
For further information download our product guide to Silicone Greases.
When combined with specialist fillers the silicone grease will allow the efficient transfer of heat from one surface to another. These materials are more precisely known as heat transfer compounds because they are not lubricants as such. Their main application is in micro-electronics where they are used to facilitate heat transfer from processors and other components to a suitable heat sink. If the component and the heat sink are simply placed together, the small air gaps that will naturally exist between them will inhibit heat transfer. By filling these gaps, the compound allows a direct path through which the heat can travel.
The ability of a material to transfer heat is quoted in W/mK - for a material to offer any significant benefit it has to have a figure above 0.4 W/mK. Standard silicone compounds will normally have a figure of 0.18 W/mK. CHT products have heat transfer compounds ranging from 0.77 W/mK up to 3.0 W/mK.
The obvious benefit of using a non-setting compound over a thermally conductive adhesive is the ease of use.
Silicone polymers have very good electrically insulating properties enabling silicone grease to be used as an electrical insulator and lubricant. On the micro level they can be used to lubricate switches, electrical contacts and cable joints.
On a much larger scale they have been used for many years on high voltage insulators to provide environmental protection and prevent arcing or corona discharge. The addition of a pink dye has enabled inspection to take place from a distance to see if the grease has remained in place.
Water repellency, combined with non-toxicity, make these greases an ideal choice for use with water pipes and fittings. CHT's SGM494 has approval for use with hot and cold potable water from the UK's Water Regulations Advisory Scheme (WRSA) ref 0502509. Applications include lubricating plastic fittings and stop taps.
Silicone grease is an excellent lubricant involving the following material interfaces:
These greases can also be used as a heavy duty mould release for the plastics and rubber industry.
Caution: Silicone grease should not be used for metal to metal high load bearings as it will cause adverse wear.