Chapter Six - Surface Modification, Deposition of Thin Films, Welding, and Cladding

Abstract

This chapter deals with the modification of surfaces, deposition and transfer of thin films, and welding and cladding under water. It begins with a discussion of the modification of surfaces of inorganic materials, indicating that laser irradiation may modify the surface of a solid by melting and vaporizing it, or by inducing chemical reactions between the solid and the ambient. It also describes the modification of surfaces of organic materials. At laser-induced high temperatures, liquids like water and liquid nitrogen, inert under normal conditions, dissociate, liberating chemically reactive species. Following this, the study takes into consideration the phenomenon of deposition and transfer of thin films. Under this, it considerslaser ablation deposition in water vapor, laser ablation deposition using a liquid target, laser ablation deposition using a frozen target, and forward transfer from solution (LIFT technique). Furthermore, it explains the process of welding and cladding under water. Welding and cladding in contact with liquids is not known to bring along any benefits, but there may be a need to do these operations under water at the repair of underwater constructions. Finally, the study states that compared with the other underwater welding methods, underwater laser welding is characterized by its low-heat input, which is a key to reduce the sensitivity of stainless steel to stress corrosion cracking.