Overview of Surface Modification Technologies

In order to be competitive in the market, it is important to be able to produce, at an acceptable cost, surfaces resistant to wear, tarnishing, and corrosion, that can retain their electrical, optical, or thermal properties over a long period. It is also important to have technologies that can simplify product ranges and maintenance requirements. Surface treatments and coatings have a prominent role to play in this respect. This chapter offers an overview of the different surface coating technologies with emphasis placed on thermal spray processes whose applications are briefly discussed. Different processes are described for a wide range of material precursors in powder, wire, rod, or cord forms as well as liquids whether suspensions or solutions. The interactions between the high-energy gas source and particles or liquids in flight are briefly described. A review of surface preparation, coating formation, and residual stresses in the substrate-coating system is given followed by highlights of industrial applications of thermal spray coating technology.