Experimental Study of Diamond-like Carbon Film on Aermet100 Steel and First-Principles Calculation of Interfacial Adhesion

Abstract

Three different types of surface-modified layers of N, C, and N+C are successfully prepared on AerMet100 steel by plasma-assisted thermochemical treatment, and diamond-like carbon (DLC) films are formed on the top surfaces of the latter two. The results show that the DLC films produced by prenitriding and then carburizing (N+C) exhibit a smoother and finer morphology and higher sp 3 content than that without prenitriding (C). In addition, the wear resistance of the N+C specimen with a high hardness nitrided layer as the support for the outermost DLC films is superior to that of the C specimen. In view of the catalytic effect of the Fe 3 C phase on the growth of DLC films, the interfacial properties of Fe 3 C(001)/diamond(111) are investigated using first-principles calculations. On the basis of the most preferred Fe-terminated HCP site model, the effects of alloyed cementite (Fe 2 MC) on interfacial adhesion of Fe 2 MC(001)/diamond(111) are also investigated. Furthermore, the mechanisms of interfacial adhesion for two representative dopings (Zr weakened and V enhanced) are revealed in detail. These results are expected to provide a potential promising means for future experimental works on the preparation of high-performance DLC films on alloy steel surfaces by plasma carburizing.

Catalytic Growth of High-Performance Graphite-like Carbon Films on a Nitrided Substrate: Experimental Study and First-Principles Calculations

“…Additionally, the hardness of GLC films fabricated in this study is relatively lower than that of GLC films obtained via other conventional methods − but closer to that of the nitrided layer, which facilitates interfacial adhesion . The higher hardness of nitrided layers provides improved support to GLC films, which would serve as a solid lubricant, reducing friction and improving wear resistance during wear processes. , The wear resistance of ceramic thin films is assessed using the ratio of hardness H to elastic modulus E ; , however, the generality of the H / E ratio is still under debate and needs further studies. The calculated H / E values are given in Table S1.…”

“…A bright-field TEM image of the interface of the 5201:1 sample with its selected area electron diffraction (SAED) pattern (inset) is shown in Figure a. The SAED pattern exhibits a polycrystalline ring-like electron pattern, indicating the presence of amorphous features at the nitrided layer–GLC film interface. , Further analysis shows that the SAED pattern contains the diffraction rings of Fe 4 N and Fe 3 N, corresponding to the (111) and (210) planes of Fe 4 N and (202), (211), and (113) planes of Fe 3 N, respectively, consistent with the XRD results. The HRTEM images of the interfacial microregions of the 5203:1, 5201:1, and 5201:3 samples with the corresponding inverse fast Fourier transform (FFT) results (as inserted) are shown in Figure b–d, respectively.…”

“…The SAED pattern exhibits a polycrystalline ring-like electron pattern, indicating the presence of amorphous features at the nitrided layer−GLC film interface. 30,31 Further analysis shows that the SAED pattern contains the diffraction rings of 5b) is covered by the Fe 3 N phase, which induces the growth of the GLC films. A continuous transition zone is present between GLC films and nitrided layers, showing a mixture of nanocrystalline and amorphous structures.…”

“…46 The higher hardness of nitrided layers provides improved support to GLC films, which would serve as a solid lubricant, reducing friction and improving wear resistance during wear processes. 25,27 The wear resistance of ceramic thin films is assessed using the ratio of hardness H to elastic modulus E; 30,31 however, the generality of the H/E ratio is still under debate and needs further studies. The calculated H/E values are given in Table S1.…”

“…At the same time, the low preparation efficiency and high production costs of dual coatings limit their large-scale production. Several studies − have reported the fabrication of self-lubricating amorphous carbon films on carburized steel surfaces via a one-step method in a plasma-assisted system. However, in these studies, the treatment temperature (400–550 °C) is too low for carburizing but too high for carbon film deposition, forming a thin carburized layer with a moderate supporting effect, and the corresponding performance of the layer is below expectation.…”