Thermal spray coatings for gate valve components

Application of coatings on gate valve components used in oilfield industry has been common for several decades. Coatings that are used for gates and seats applications have to meet stringent service requirements. HVOF, D-gun and Super D-gun processes provide enhancements to surface properties by improving wear and corrosion resistance as well ensuring an effective sealing between  functional surfaces.
This paper reviews the applicable coating materials, presents several testing methods, and provides the key properties of such coatings.