In-situ monitoring of plasma enhanced nitriding processes using infrared absorption and mass spectroscopy

• Published in: Surface & coatings technology Vol. 206; no. 19-20; pp. 3955 - 3960
• Main Authors: Burlacov, I., Börner, K., Spies, H.-J., Biermann, H., Lopatik, D., Zimmermann, H., Röpcke, J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25-05-2012; Elsevier
• Subjects: Activation; Active screen; Applied sciences; Coatings; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Heat treatment; Infrared absorption; Ion nitriding; Materials science; Metals. Metallurgy; Mid infrared tunable diode laser absorption; Nitriding; Physics; Plasma diagnostics; Plasma nitriding; Process parameters; Production techniques; Quadruple mass spectroscopy; Surface chemistry; Surface treatments; Thermochemical treatment and diffusion treatment; Active screen; Plasma nitriding; Mid infrared tunable diode laser absorption; Quadruple mass spectroscopy; Thermochemical treatment; Plasma; Infrared spectroscopy; Absorption; In situ; Nitridation; Surface treatments
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2012.03.067

The active screen (AS) nitriding is an advanced technology for the plasma nitriding of steel components providing a number of advantages over conventional plasma nitriding. Developed in the last decade, the AS technology has found its industrial application, however the understanding of the fundamental mechanisms and their relationship is not complete. For the first time the mid infrared tunable diode laser absorption technique in combination with the quadruple mass spectrometry has been applied in this work. In-situ diagnostics of chemical phenomena in the N2–H2 plasmas under variation of the process conditions such as H2 to N2 gas ratio, process temperature and bias activation power provided valuable information about the concentration of active nitrogen species in the vicinity of the samples' surfaces. The thickness of the compound layer representing the nitriding efficiency was used as a response to nitriding conditions for the evaluation of selected process parameters derived from the plasma diagnostic studies. A 1:1 gas mixture of the N2–H2 process gases seems to be most effective to get thick compound layers.
► ASPN is a novel plasma assisted nitriding technique for a surface-engineering treatment. ► Two plasma diagnostic methods: mid IR TDLAS and QMS were in-situ applied. ► A 1:1 gas mixture of the N2–H2 process gases is favorable to get thick compound layers.