**Abstract**

Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical or chemical. The study of wear and related processes is known as tribology. Abrasive wear alone has been estimated to cost 1–4% of the gross national product of industrialized nations. The current chapter focuses on types of wear phenomena observed in the industries (such as abrasive wear, adhesive wear, fretting wear, fatigue wear, erosive wear and corrosive wear), their mechanisms, application of surface coating for the protection of the surface from the industrial wear, types of surface coatings, thermal spray coating, types of thermal spray coating and its application in industry to protect the surface from wear. The detail information about the wear phenomena will help the industries to minimize their maintenance cost of the parts.

**Keywords:** wear, type of wear, tribology, surface coating, thermal spray coating

## **1. Introduction**

Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical also called as erosion or chemical also called as corrosion. Wear of metals occurs by plastic displacement of surface and near-surface material and by detachment of particles that form wear debris. In material science, wear is the erosion of material from a solid surface by the action of another solid. The study of the process of wear is the part of the theory of tribology. Wear in machine components, along with different cycles, for example, fatigue and creep, makes surfaces deteriorate, in the end prompting material degradation or loss of applicability. Subsequently, wear has enormous monetary significance as first mentioned in the Jost Report. Abrasive wear alone has been assessed to cost 1–4% of the gross national product of industrialized countries. Wear of metals happens by plastic dislodging of surface and close to surface material and by separation of particles that produce wear debris. The molecule size may change from millimeters to nanometers. This cycle may happen by contact with different metals, nonmetallic solids, streaming fluids, solid particles or fluid beads entrained in streaming gasses. The wear rate is influenced by components, for example, sort of stacking (e.g., stationary and active), kind of movement (e.g., gliding and continuing), surrounding temperature, and lubrication, specifically by the cycle of deposition and deterioration of the boundary lubrication layer. Contingent upon the tribosystem, diverse wear types and wear systems can be watched.
