Conductive grease typically serves as a path to earth or ground in a customer component or device. For example, any rotating component supported by ball bearings is essentially isolated from the rest of the device by the lubricant in the bearing raceway; a conductive bearing grease is the solution to avoid the build up of static electricity. Conductive grease also has other uses, for example a rail transportation carriage manufacturer relies on our conductive grease to ensure there is a path to earth throughout their rolling stock body to chassis mechanical connections.
If static discharge poses a hazard in your application or device, consider a high performance conductive grease.
There are two products that are the most popular formula from the conductive grease range – Like all things lubrication, there isn’t a ‘one size fits all’ conductive grease that can be used for every application. Identifying which product is most suitable can be simplistic but we always endeavour to make sure customers are aware of chemistry limitations; that said, the three formulations below usually cover about 80% of the conductive grease requirements from customers. If neither of the products below is suitable, just Contact Us for some advice. You may also want to read our short Electrically Conductive Grease introduction article.
Conductive bearing grease applications are by far the most common requests from customers so here are a few guidelines to help you select the best electrically conductive grease for you bearing:
- Ester base oils are best for metal on metal, demanding applications.
- Choosing a grease with a base oil viscosity of between 4 and 20 cSt at the typical bearing operating temperature is a good rule of thumb.
- Don’t confuse base oil viscosity with finished grease stiffness.
- A higher viscosity base oil viscosity is better for lower speed bearings and obviously a lower base oil viscosity for higher speeds (less drag).
- None of our synthetic grease formulations use metal particles to achieve conductivity.
- Sometimes with conductive bearing applications, a slightly higher percentage grease fill is often required.
One of our two most popular electrically conductive synthetic greases are usually suitable for most customer tasks/applications:
Tribosyn 362G
- Recommended temperature range of -40 to 125°C
- Polyalphaolefin (PAO) base oil makes this grease a great ‘all rounder’.
- Conductivity achieved by use of conductive carbon thickener system.
- Base oil kinematic viscosity of 57 cSt at 40°C.
- Rust inhibitor additive included in the formula.
- Good levels of compatibility with plastics.
- Volume resistivity 62 Ω-cm.
- NLGI grade 2.
Tribosyn 610
- Recommended temperature range of -40 to 150°C
- Ester base oil used for excellent metal wear resistance in demanding bearing applications.
- Conductivity achieved by use of conductive carbon thickener system.
- Low oil separation, thereby (in bearings) maintaining electrical continuity between ball and race.
- Excellent resistance to oxidative degradation.
- Ester base oils can’t cope with high moisture levels.
- Ester oil based greases can have compatibility issues with some plastics, if this is an issue consider the Tribosyn 362G (PAO base oil).
- A superb pedigree in ATEX environment bearing applications.
- Volume resistivity is 100 Ω-cm.
- NGLI grade 3.
Looking for higher temperature range capabilities? – Ester and PAO base oils have upper temperature limits of about 150C and 125C respectively. Need a conductive grease with a higher temperature capability? The two products mentioned on this article generally are the most popular but we do have conductive greases that deal with higher temperatures. A conductive grease using a Perfluoropolyether (PFPE) base oil would probably be necessary for very high temperatures. PFPE’s are great at dealing with high temperatures but not so good with high loads and PFPE’s are at the top end of the price range so if you need a high temperature conductive grease, please get in contact and we’ll be happy to discuss this matter with you.
We have an electrically charged bearing wear test that the viewer might consider watching.
A conductive grease has many potential applications. We chose a bearing application to demonstrate the effectiveness of one particular grease in the range:
Take a look at the other articles we have associated with conductive grease the at our tech support site (opens in new tab/window).
