General Knowledge - General Science - Discussion

How can we say that only graphite is used as lubricant, silica is also used as lubricant without any clarification in question?

We can also use the silica gel as lubricant.

Graphite is used as lubricant under high temperature conditions where petroleum based lubricants loss their viscosity.

@Nikita.

Because it much stable chemically as temperature. I think 6.

Can anybody give example where Graphite used as lubricant?

Graphite is best suited for lubrication in air. Water vapor is a necessary component for graphite lubrication. The adsorption of water reduces the bonding energy between the hexagonal planes of the graphite to a lower level than the adhesion energy between a substrate and the graphite. Because water vapor is a requirement for lubrication, graphite is not effective in vacuum. Because it is electrically conductive, graphite can promote galvanic corrosion. In an oxidative atmosphere graphite is effective at high temperatures up to 450°C continuously and can withstand much higher temperature peaks.

Do you all know what are covalent bonds ?

Lubricant is a substance used to reduce the friction between two or more substances.

Different layers of graphite are connected together by weak Van der waal's force. This causes the layers to slip over one another. So, graphite is used as a lubricant.

Graphite contain sheets of atoms. This sheet are weakly bounded with other sheet these sheets are can easily separated. That's why graphite act as lubricant.