| 摘要 |
PURPOSE:To provide the titled tungsten filament without obstacles such as deterioration of insulation or the like and with extremely low cost by growing tungsten hexafluoride in the vapor phase onto the surface of a tungsten wire processed into a predetermined shape to form a pure tungsten layer. CONSTITUTION:A conventional tungsten wire 9 processed into a predetermined shape is placed in a heating chamber 6 provided with a heater 5 therein and tungsten hexafluoride 3 evaporated by passing H2 into a liquid of tungsten hexafluoride 3 in a glass container 1 placed in a thermostatic oven 2 is introduced into the heating chamber 6 and, herein, the pure tungsten layer 10 is grown in the vapor phase onto the surface of a coil like filament 9 by the reducing reaction to obtain the titled filament. If the vapor deposition is carried out by using this filament, because Na or the like contained within a tungsten wire in minute amount is not issued out by evaporation, an electric terminal with good quality equal to a tantulum filament which is about 6 times more expensive than the tungsten filament. |
