Introduction: Thermal Spray Coatings and their Historical Developments

Thermal spray coatings are a method of surface modification in which various metallic and non-metallic materials are sprayed in molten, semi-molten, or even solid state on a prepared substrate. The coating material is present in two forms: wire or powder. The most common thermal spraying techniques include cold spray, electric arc spray, plasma spray, detonation gun spray, flame spray, and high-velocity oxy-fuel spray. The coating's thickness, which is calculated in millimeters or microns and has distinguishing features from the base material's surface, is acceptable in many industrial sectors and is ideal for on-site industrial applications. These processes also offer affordable solutions in many industrial sectors and are capable of providing surface modification approaches with enhanced surface properties comprising better texture and high mechanical strength in terms of hardness, scratch resistance, and porosity. This chapter presents the evolution of coatings developed during the last few decades using various coating processes and materials for the protection of service components. Coating measures are developed for use in thermal power plants, gas steam, and the automotive industry for the treatment of components, able to work in harsh environments of flue gases and chemicals.

Keywords: Coating evolution, Cold spraying, Coating structure, Coating thickness, Flame Temperature, Feedstock material, Oxidation resistance, Particle velocity, Surface treatment, Surface modification, Thermal power plant, Thermal spray coatings.