Abstract: A high velocity, oxygen fuel ("HVOF") thermal spray gun for spraying a melted powder composition of, for example, thermoplastic componds, thermoplastic/metallic composites, or thermoplastic/ceramic composites onto a substrate to form a coating thereon. The gun includes an HVOF flame generator for providing an HVOF gas stream to a fluid cooled nozzle. A portion of the gas stream is diverted for preheating the powder, with the preheated powder being injected into the main gas stream at a downstream location within the nozzle. Forced air and vacuum sources are provided in a shroud circumscribing the nozzle for cooling the melted powder in flight before deposition onto the substrate.

Abstract: Improved polyamide-based compositions are provided which are particularly formulated for plasma-spray application to surfaces subjected to acidic conditions. The compositions include respective amounts of polyvinylidene fluoride, a polyamide (e.g., Nylon 11) and a compatable adhesive such as a nylon terpolymer adhesive.

Abstract: An improved, environmentally safe protective coating for marine surfaces is provided which is specially formulated for application to boat hulls for resisting marine growth thereon while minimizing release of toxic antifoulants into the environment. The coatings of the invention can therefore be used on boat hulls for preventing marine growth without the severe pollution effects associated with conventional antifoulant paints. The coatings are preferably made from powdered mixtures which include respective quantities of Nylon 11, an inorganic porous carrier such as carbon black, and an antifoulant such as tributyltin fluoride.

Abstract: An improved, relatively permanent operating head for stud welding guns is provided which eliminates the need of ferrule replacement after each welding sequence, thereby greatly speeding up and facilitating the welding operation, and lowering the cost thereof. The head includes an elongated, metallic, notched, dielectric-covered ferrule surrounding the usual stud-conveying chuck provided with the gun, along with air cooling apparatus for directing circumferentially spaced air currents through and exteriorly of the permanent ferrule to extend the life thereof and minimize buildup of slag thereon. In preferred forms, an inner, electrically insulating phenolic sleeve is disposed between the chuck and ferrule, and the work end of the latter is coated with an initial layer of tungsten carbide and an outer layer of tantalum for maximum heat resistance and electrical insulation.