Abstract A nanocrystalline layer was fabricated on the surface of 42MnCr52 steel by ultrasonic surface rolling processing (USRP). Plasma sulfonitrocarburizing (PSNC) was performed on the untreated surface and nanostructure surface to obtain a composite layer composed of the solid lubrication layer (FeS) and nitrocarburized subsurface layer. The effect of the nanocrystalline layer on PSNC was investigated using phase analysis, microstructural analysis, element analysis, hardness analysis, and wear property analysis. The results are as follows: The average grain size of the gradient nanostructure surface was about 40 nm. A more compact and homogeneous sulfide composite layer was formed on the surface of the USRP + PSNC specimen, and the sulfide composite layer was mainly composed of an FeS phase with excellent solid lubrication properties. The thickness of the nitrocarburized layer was increased by 130% on average and its homogeneity also improved after USRP. The hardness value of the subsurface (nitrocarburized layer) of the USRP + PSNC specimen was higher than that of the PSNC specimen. The wear volume and frictional coefficient of the USRP + PSNC specimen were obviously lower than those of the PSNC specimen. The USRP + PSNC specimen exhibited strong wear resistance.

中文翻译：

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梯度纳米结构对42MnCr52钢等离子碳氮共渗的影响

摘要 采用超声波表面滚压加工(USRP)在42MnCr52钢表面制备了一层纳米晶层。在未处理的表面和纳米结构表面上进行等离子体磺基碳氮共渗（PSNC），以获得由固体润滑层（FeS）和氮碳共渗亚表面层组成的复合层。使用相分析、显微结构分析、元素分析、硬度分析和磨损性能分析研究了纳米晶层对PSNC的影响。结果如下： 梯度纳米结构表面的平均晶粒尺寸为约40nm。USRP+PSNC试样表面形成了更致密均匀的硫化物复合层，硫化物复合层主要由具有优异固体润滑性能的FeS相组成。USRP 后，氮碳共渗层的厚度平均增加了 130%，均匀性也有所提高。USRP + PSNC 试样的次表面（氮碳共渗层）硬度值高于 PSNC 试样。USRP+PSNC试件的磨损量和摩擦系数明显低于PSNC试件。USRP + PSNC 试样表现出很强的耐磨性。