Surface engineering is the use of coatings and treatments to improve selected properties of functional surfaces of solids. It includes all coatings and all treatments to surfaces. The processes range from covering surfaces with nano-sized surface texture features to fusion hardfacing with welding techniques. The surface engineering processes that have significant applicability for tribocomponents are shown in Figure 14.1. This chapter will describe those processes as they may be used for tribocomponents to solve friction wear and erosion problems.