Electrical greases are used to reduce sliding contact friction and wear, minimize surface oxidation, provide moisture and chemical exclusion, and minimize arc erosion. Electrical greases can be separated into two categories: Low current (non-arcing) and High current (arcing) and are discussed separately.

Low Current Interfaces

Low current (non arcing) switching of 100 millivolts or less at 5 to 25 volts DC requires excellent metal oxidation protection against corrosion, humidity protection, mechanical anti-wear and mechanical and chemical stability. Typically, low current switch interfaces have failure modes related to storage and inactivity as opposed to high current switch interfaces where cycle life failures are the norm. Metal choices for low current interfaces are particularly critical for long service life. Noble metals and nickel finishes are high performers. Copper and copper alloys tend to be highly reactive in temperature/humidity conditions and oxidize readily. If not protected against temperature and humidity conditions degradation of the metals occur rendering the lubricant useless. Syn-Tech can provide contact lubricants that will allow the use of copper in low current switches without having to resort to silver or nickel plating.

Base fluids, additives and thickeners have to be chosen carefully for low current situations. Sliding switches may roll or deflect before moving causing momentary interrupts in circuits. This can be the result of mechanical design, coefficient of friction, hydro-planning or simply entrapping particles, thickener, dust etc. between the contacts.

With cycle life, the contact interface patch grows in area, reducing contact pressures making scrubbing or displacement of oxides and debris even more difficult.

NS-12001-G

NS-7696-G1

High Current Interfaces

Under high current conditions, greases are subjected to extended cycles at plasma arc temperatures usually +1000°C or higher. This oxidizes base fluids and generates arc debris and creates electrically conductive particles. Development of greases suitable for these conditions requires considerations of oxidation stability, evaporative loss, material compatibility, thickening and additive systems and electrical isolation properties of the arc debris with the contact metals.

NS-2402-G

NS-12001-G

NS-13889-G