Improvements in or relating to methods of sealing silver-plated ferrochromium discs in glass in a vacuum-tight manner and electric discharge tubes provided with such seals

摘要

A ferrochromium disc is coated with a very thin nickel or cobalt layer, then a very thin gold layer, then a thick silver layer after which it is heated in a chromium-oxidizing atmosphere at 900-1000 DEG C. until a chromium-oxide layer is formed on the surface of the silver layer, and is sealed to a glass part, preferably during the same heating operation. The very thin layers are less than 0.2 microns thick and the silver layer exceeds 2 microns. Heating may take place in a humid nitrogen-hydrogen gas mixture with 12 to 25% of hydrogen, or in air. The glass part may be a glaze previously applied to a ceramic body.