AISI 420 martensitic stainless steel low-temperature plasma assisted carburizing kinetics

作者：Scheuer C J; Cardoso R P^*; Mafra M; Brunatto S F

来源：Surface and Coatings Technology, 2013, 214: 30-37.

DOI：10.1016/j.surfcoat.2012.10.060

• Low-temperature plasma assisted carburizing
• AISI 420 martensitic stainless steel
• Plasma carburizing kinetics

The present paper reports the experimental results on martensitic stainless steel low-temperature plasma assisted carburizing kinetics. The treatments were carried out using a gas mixture of 99.5% (80% H-2 +20% Ar) + 0.5% CH4 at temperatures of 623, 673,723 and 773 K and for times of 4, 8, 12 and 16 h. The peak voltage and the pulse period of the pulsed DC power supply were kept constant at 700 V and 240 mu s, respectively. Temperature was controlled by adjusting the duty cycle. The treated samples were characterized by confocal laser scanning microscopy, X-ray diffractometry and microhardness measurements. Results indicate that low-temperature plasma carburizing is a diffusion controlled process. The calculated activation energy for outer and diffusion layer growth was 29 and 85 kJ mol(-1), respectively. An apparently precipitation-free layer can be produced only when the processing temperature is sufficiently low (<= 723 K) and time sufficiently short (<= 12 h).

• 出版日期2013-1-15