Untersuchungen zum Verständnis der chemischen Reaktionen beim Nitrocarburieren in Salzschmelzen

Materials samples have been nitrocarburized in a salt bath under a vacuum or an argon atmosphere. The compound layer thickness was reduced by 30 to 50 % compared with a treatment in air. The nitrocarburization in salt melts thus is based on two competitive reactions which run parallel to each other, one is the oxidation of the cyanate ion, the other is the decomposition of the cyanate anion on the surface of the workpiece. The decomposition reaction contributes more to the nitrocarburization than it was assumed up to now and is probably depending on the material itself. As a consequence it is useful to adjust the activity of nitrocarburizing salt baths to the materials to be treated. Apart from the temperature and the cyanate concentration a very important element for the control of the nitrocarburizing activity is the cationic composition of the salt melt.