Effect of Cooling Rate on Plasma Nitrocarburised Compound Layers for Pure Iron = Effect of Cooling Rate on Plasma Nitrocarburised Compound Layers for Pure Iron

다국어 초록 (Multilingual Abstract)

Plasma nitrocarburising was carried out with various CO gas compositions with 3 mbar at 570℃ for 3 hours. After treatment, different cooling rates (fast cooling, slow cooling and gas cooling) were used to investigate their effect on the structure of the compound layer, the ε phase being the outer part of the compound layer and the γ phase being the inner part. The CO gas composition influenced the constitution of the compound layer produced, I.e. high CO contents were essential for the production of an ε phased compound layer, as did a variation of the cooling rate, with a large amount of γ phase transformed from the εphase during slow cooling. The transformation was reduced with an increasing cooling rate and prevented by a fast cooling rate of approximately 18.5℃/sec at 500℃, at which temperature this transformation began.