Electrical Articles Archive
Application of solid lubricants
The application of solid lubricants are- They are used either in the form of dry powered or mixed with water or oil so that they may stick firmly to the metal surfaces the suspension is stabilized by
Why can graphite act as a good lubricant on the surface of the moon?
The temperature on the moon is 1000C and -1500C during day and night time respectively. Oils and greases cannot withstand such temperature changes but graphite is unaffected within this temperature range. Hence, it acts as good lubricant
Structure and properties of graphite
Solid lubricants generally have a laminar structure Structure of graphite Graphite has a layered lattice structure as shown in fig.3.5. The sp2 hybridized carbon atoms are arranged in flat parallel layers. Each carbon atom is linked to
Used of solid lubricants
A solid lubricant is used in situations such as- Heavy machinery working at very loads and slow speeds. Where parts to be lubricated are not easily accessible. Where a liquid or a semi-solid lubricant film cannot be
Distinguish between thick film and boundary film lubrication
The difference between thick film and boundary film lubrication are as follows- Thick film Boundary film lubrication It is also known as film or hydrodynamic lubrication. It is also known as thin film lubrication. In this case,
Classification of lubricants
The classification of the lubricants is they are classified on basis of their physical state as- Solid lubricants E.g.: Teflon, talc, graphite, molybdenum dissuade Semi-solid lubricants E.g.: greases, wax, Vaseline Liquid lubricants These are further classified on
What is extreme pressure lubrication
Operation conditions: High speed and extremely high temperature High pressure and extreme load When the moving or sliding surfaces are under very high pressure and speed, excessive frictional heat will be generated. The high local temperature thus
What is boundary film
Boundary film or thin film lubrication Operating conditions : This type of lubrication is applied when a continuous fluid-film cannot be maintained and direct metal to metal contact is possible due to certain reasons Shaft comes into
Hydrodynamic lubrication
Fluid film or hydrodynamic or thick film lubrication Operating conditions: Low load Uniform temperature Moderated speed In this type of lubrication, the sliding metals surfaces or rotating metal surfaces are completely separated from each other by applying
What is surface roughness?
The best-polished metal surface, when examined under electron microscope showed rough surface having peaks and valleys of different heights and depths, is surface as surface roughness. The highest peaks are known as asperities. When two such flat