Parameter settings in a compact laser-nitriding system for titanium composed of a focused pulsed Nd:YAG laser and nitrogen gas blow |
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Authors: | Naofumi Ohtsu Wataru Saito Misao Yamane |
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Institution: | School of Earth, Energy and Environmental Engineering, Kitami Institute of Technology, Kitami, Japan |
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Abstract: | The aim of the present study was to form a nitride layer on a titanium (Ti) substrate through a compact laser-nitriding system comprising a focused pulsed Nd:YAG laser and nitrogen gas blow. To obtain a high-quality layer, the effects of pulse frequency and gas flow rate on the surface characteristics were investigated by using plasma emission analysis as well as X-ray analyses. Optical emission spectra from the laser-induced plasma mainly consisted of ionic Ti lines, and their intensities when the pulse frequency was 15 Hz were much higher than those for 8 Hz. Similarly, the reflections from the δ-TiN phase in the X-ray diffraction (XRD) pattern were enhanced when using 15 Hz. On the other hand, the flow rate of nitrogen gas blow had a significant effect on the thickness of the thin oxide layer that formed above the nitride layer. Using a lower flow rate resulted in the formation of a thicker oxide layer. The higher pulse frequency and the faster flow rate were beneficial for obtaining a higher-quality layer because of the enhancement of nitridation and the suppression of oxidation, respectively. |
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Keywords: | gas-blowing speed laser nitriding of titanium laser pulse frequency optical emission spectra surface analysis |
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