Abstract: There are provided a thermal spraying method and a thermal spraying apparatus therefor, in which a gas shroud is disposed in an HVOF thermal spraying gun barrel, the velocity of metallic particles is energized and accelerated with respect to the metallic particle to be thermally sprayed from the gun, and inert gas is supplied into the space defined inside of the shroud through a circumferential slit formed in such a manner as to shield the metallic particles from the atmosphere so as to collide with the surface of a base member, thereby forming a thermally sprayed dense film having a small oxygen content without overheating the base plate by an HVOF method.

Abstract: In a laser welding method, the invasion of atmosphere gas into a molten metal and the occurrence of welding defects are prevented by coating a material having a high affinity for the atmosphere gas on the back surface of a work and therefore it is possible for a large output laser to easily weld a thick plate by employing a simple method.