| 摘要 |
PURPOSE:To prevent the abnormal boiling induced by oxide films, by lowering once the level of the molten metal supplied to a crucible for evaporation and reducing the metallic oxides sticking and remaining in the crucible for evaporation with carbon then starting vacuum deposition. CONSTITUTION:The inside of a vacuum deposition chamber 4 is evacuated through an evacuation port 16 and molten Zn 6 is once supplied into a crucible 5 for evaporation in the stage of starting a vacuum deposition device which deposits the molten Zn 6 supplied through a communicating pipe 8 from a melting furnace 7 in the atmosphere into the crucible 5 on a steel strip 1 that travels through sealing rolls 14 in the chamber 4. An inert gas is then introduced into the chamber 4 or the level in the furnace 7 is once lowered by a level adjusting mechanism 11 to retreat the surface of the molten Zn down to the upper part in the pipe 8. The Zn oxide film 21 sticking and remaining on the inside wall of the crucible 5 is heated with heaters 9, 12, and is reduced with a carbonaceous reducing agent 22 charged beforehand in the crucible. After the film is thus removed as Zn and CO, the level of the molten Zn 6 is again raised into the crucible and the vapor deposition is started. |
