Function of various constituents in greases

Soap

• It acts as a thickener.
• Presence of soap allows it to stick to the metal surfaces firmly and provides consistency.
• The nature of soap decides the temperature to which the greases can be used.
• It provides resistance to water, oxidation and breaking up of film on prolonged use. Thus, the nature of soap decides the working temperature, consistency, load-bearing capacity, resistance to water coefficient of friction.

Oil

• It remains in the dispersed phase and maintains the greases in the solid state.
• Sometimes, it provides viscosity to the greases.
• The nature of oil decides the viscosity of grease.

Fillers

• It reduces the cost of grease.
• It provides heat cost grease to grease.
• Fillers like graphite , MoS₂ etc adds to the lubricating property of greases.