AISI 321, an austenitic stainless steel, has high corrosion and temperature resistance, making it useful for aerospace and chemical processing. Cathodic cage plasma nitriding (CCPN) is a versatile technique that enhances material surface characteristics. This study aims to investigate the effect of the pulsed duty cycle from 10 % to 60 % on microhardness and tribological properties through CCPN treatment. The X-ray diffraction (XRD) analysis indicates a noticeable shift in the γ-phase towards the lower 2θ angle originating from the expanded austenite phase by the lattice expansion at the lowest duty cycle. Nitriding at the lowest duty cycle reduced the average crystallite size from 68 nm (untreated) to 4.5 nm, while increasing the duty cycle led to a decrease in micro-strain. The surface microhardness of the sample that underwent the lowest duty cycle improved to 1288 HV compared to the untreated sample (210 HV). Moreover, the lowest wear rate is observed for the sample nitrided at a low-duty cycle, which agrees with hardness and strain behavior. The results show that the variable pulsed duty in CCPN can improve the surface hardness and tribological properties of AISI 321, particularly at low-duty cycles.

中文翻译：

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通过不同脉冲占空比的阴极笼式等离子渗氮提高 AISI 321 的硬度和摩擦学性能


AISI 321 是一种奥氏体不锈钢，具有高耐腐蚀性和耐高温性，使其可用于航空航天和化学加工。阴极笼式等离子渗氮 (CCPN) 是一种增强材料表面特性的通用技术。本研究旨在通过 CCPN 处理研究 10% 至 60% 的脉冲占空比对显微硬度和摩擦学性能的影响。 X 射线衍射 (XRD) 分析表明，γ 相明显向较低 2θ 角移动，这是由于最低占空比下的晶格膨胀导致奥氏体相膨胀。最低占空比下的渗氮将平均微晶尺寸从 68 nm（未处理）降低到 4.5 nm，同时增加占空比导致微应变降低。与未经处理的样品 (210 HV) 相比，经历最低占空比的样品的表面显微硬度提高至 1288 HV。此外，在低负荷循环下氮化的样品中观察到最低的磨损率，这与硬度和应变行为一致。结果表明，CCPN 中的可变脉冲负载可以提高 AISI 321 的表面硬度和摩擦学性能，特别是在低负载循环下。