Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel

Liu, Dongjing; You, Yuan; Yan, Mufu; Chen, Hongtao; Li, Rui; Hong, Lin; Han, Tingjie

doi:10.3390/coatings11091122

Open AccessArticle

Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel

by

Dongjing Liu

¹,

Yuan You

^1,2,*,

Mufu Yan

²,

Hongtao Chen

³,

Rui Li

¹

,

Lin Hong

¹ and

Tingjie Han

¹

School of Materials Science and Engineering, Qiqihar University, Qiqihar 161006, China

²

National Key Laboratory of Metal Precision Thermal Processing, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China

³

School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China

^*

Author to whom correspondence should be addressed.

Coatings 2021, 11(9), 1122; https://doi.org/10.3390/coatings11091122

Submission received: 3 August 2021 / Revised: 29 August 2021 / Accepted: 10 September 2021 / Published: 16 September 2021

(This article belongs to the Special Issue Surface Engineering of C/N/O Functionalized Materials)

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Abstract

In order to explore the effect of the addition of rare earth (RE) to a steel microstructure and the consequent performance of a nitrided layer, plasma nitriding was carried out on 38CrMoAl steel in an atmosphere of NH₃ at 550 °C for 4, 8, and 12 h. The modified layers were characterized using an optical microscope (OM), a microhardness tester, X-ray diffraction (XRD), a scanning electron microscope (SEM), a transmission electron microscope (TEM), and an electrochemical workstation. After 12 h of nitriding without RE, the modified layer thickness was 355.90 μm, the weight gain was 3.75 mg/cm², and the surface hardness was 882.5 HV_0.05. After 12 h of RE nitriding, the thickness of the modified layer was 390.8 μm, the weight gain was 3.87 mg/cm², and the surface hardness was 1027 HV_0.05. Compared with nitriding without RE, the ε-Fe_2-3N diffraction peak was enhanced in the RE nitriding layer. After 12 h of RE nitriding, La, LaFeO₃, and a trace amount of Fe₂O₃ appeared. The corrosion rate of the modified layer was at its lowest (15.089 × 10⁻² mm/a), as was the current density (1.282 × 10⁻⁵ A/cm²); therefore, the corrosion resistance improved.

Keywords: 38CrMoAl steel; plasma nitriding; microhardness; corrosion resistance; modified layer

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MDPI and ACS Style

Liu, D.; You, Y.; Yan, M.; Chen, H.; Li, R.; Hong, L.; Han, T. Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel. Coatings 2021, 11, 1122. https://doi.org/10.3390/coatings11091122

AMA Style

Liu D, You Y, Yan M, Chen H, Li R, Hong L, Han T. Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel. Coatings. 2021; 11(9):1122. https://doi.org/10.3390/coatings11091122

Chicago/Turabian Style

Liu, Dongjing, Yuan You, Mufu Yan, Hongtao Chen, Rui Li, Lin Hong, and Tingjie Han. 2021. "Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel" Coatings 11, no. 9: 1122. https://doi.org/10.3390/coatings11091122

APA Style

Liu, D., You, Y., Yan, M., Chen, H., Li, R., Hong, L., & Han, T. (2021). Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel. Coatings, 11(9), 1122. https://doi.org/10.3390/coatings11091122

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Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel

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