Abstract: An attachment for supersonic thermal spray equipment by which inert shield gas is directed radially outwardly about the central core of a supersonic, particle-carrying flame to isolate the same from ambient atmosphere. The shield gas is injected tangentially against the inner surface of a constraining tube attached to and extending from the discharge end of the thermal spray gun nozzle, causing the shield gas to assume a helical flow path which persists until after it exits the tube and impacts the work piece. A process using the shielding apparatus with a high-velocity, thermal spray gun and employing oxygen and hydrogen as gases of combustion and inert gas to introduce metal powder, having a narrow particle size distribution and low oxygen content, into the high-velocity combustion gases, produces significantly improved, high-density, low-oxide metal coatings on a substrate.

Abstract: Disclosed is a process for the polymerization of olefins wherein olefinic compounds are separated from mixtures containing them with resulting improved utilization of olefinic compounds. Such olefinic compounds are separated by use of membrane separation units and can be recycled to a polymerization zone.