Lubricant Research Paper

INTRODUCTION

Lubricants are the substances that that are added to reduce friction between two surfaces [1].

Friction is simply defined as an opposing force which tends to come into action when one body is actually moving or even trying to move over the surface of the other [2]. It occurs due to the presence of certain asperities on the surface of a body. Friction can be divided into two main categories: TABLE 1: CLASSIFICATION OF FRICTION

STATIC FRICTION:

It is the opposing force which tends to come into action when one body is moving over the surface of other, without the actual motion being started [3].

LIMITING FRICTION:

It is the maximum opposing force which comes into action when a body is just about to move over

SOLID LUBRICANTS [9]

These are the lubricating systems that exist in solid states. These generally act as fillers, filling the asperities or the regularities of the surfaces inorder to make it smooth. These types of lubricants are generally used in the following cases:

• Where contamination due to dust and dirt particles has to be avoided.

• Where combustible lubricants cannot be used.

• Where the operating conditions are such that the liquid or semisolid lubricants do not remain in place due to high temperature, pressure etc.

The best examples of such lubricants are graphite, molybdenum disulphide, talc, soapstone, mica etc.

Graphite and molybdenum disulphide has a layered structure. The layers are held by Vander Waals forces of interaction. Graphite is non-inflammable and can be used up to a temperature range of 375degree Celsius, in the presence of air. While molybdenum disulphide is stable in air up to 400 degree Celsius.

Fig 3: EXAMPLES OF SOLID LUBRICANTS

Solid lubricants can be used both in the dry state and in the wet state, mixed with a solvent. If the solvent used is water, it is called as aqua dag which finds great applications in the packaging of food and other edible products as it prevents spoilage. But if the solvent used is oil, then the system is termed as oil dag which finds great use in the internal combustion