Plasma spraying involves the spraying of molten or heat-softened material onto a surface to provide a coating, using inert gases as plasma gas and carrier gas. In plasma spraying process, the material to be deposited — typically as a powder, sometimes as a liquid, suspension or wire — is introduced into the plasma jet, emanating from a plasma torch. In the jet, where the temperature is on the order of 20,000 K or more, the material is melted and propelled towards a substrate. There, the molten droplets flatten, rapidly solidify and form a deposit. Typical plasma gases are argon, helium, nitrogen and hydrogen. Single gas or mixtures can be used.