Activity modification of a new type of carbamide-based non-polluting solid powdery medium used in the sulphonitrocarburising process

Abstract

Carbamide (technical grade urea) is frequently used as a highly efficient active component in the mediums used for ferritic or austenitic nitrocarburising processes, and across a wide range of temperature values, ranging from values below 590°C required for achieving the ferritic nitrocarburising process, to values above 800°C required for the austenitic nitrocarburising process. The carbamide activity generates a particularly intense layer of growth kinetics. This paper studies the ability of carbamide to supply nitrogen and carbon, in the temperature range 550-950°C. It was concluded that this process varies by temperature, and for a composition of the solid powdery medium (35% carbamide, 50% carbon, 10% sulphur and 5% ammonium chloride) at 820°C the carbon potential level is higher compared to the nitrogen one.