| 摘要 |
The salt bath contains potassium cyanate and/or sodium cyanate and has air flowing through it. Based on the total weight, the salt bath contains 25-57% by weight of cyanate, calculated as cyanate ion and optionally up to 5% by weight of cyanide, calculated as cyanide ion. Regeneration of the salt bath is effected by adding at least one polymeric carbon/nitrogen compound without removing used salts. In general the salt bath additionally contains sodium carbonate and/or potassium carbonate and may also contain alkali metal chloride. The process is environmentally safe, since owing to the small amounts or absence of cyanide, no toxic effluents are produced. The salt melt has a low viscosity, so that drag-out losses can be kept low. Alloyed and non-alloyed steels of any carbon content and iron can be nitrided to form good nitrided layers. |
