摘要
CrMoN/SiN x multilayered coatings were fabricated by controlling the shutter-open time of two sputtering guns in a radio frequency magnetron sputtering system. Employing the structure of nacreous shells from nature, nano-crystalline and amorphous monolayers were periodically stacked. CrMoN/SiN x thin films with different bi-layer periods were deposited on Si-wafer and Inconel-718 substrates. The phases of the coatings were examined using a grazing incidence X-ray diffraction (XRD) technique. Information of chemical composition was obtained by field emission electron probe micro-analyzer (FE-EPMA). The confirmation of multilayer structure was observed by transmission electron microscope (TEM). The wear tracks were revealed by scanning electron microscope (SEM). Mechanical and high-temperature tribological properties were evaluated using a nano-indenter and a high-temperature tribometer, respectively. Grain refinement phenomenon was verified using XRD peak broadening at high angles, indicating inhibition in the column structure and the formation of an amorphous phase. CrMoN/SiN x exhibited higher high-temperature wear resistance for a specific bi-layer period, which was attributed to the multilayer strengthening mechanism. Multilayered structure provided tremendous benefit to COF improvement, which was reduced by 50% of the value of CrMoN. Simultaneously, the toughening effect of the biomimetic structure design improved the wear resistance ability of the coating. Especially, the slight amount of SiN x unpredictably enhanced the wearing properties of the system, which is in consistent with the role of chitin in nacre. Moreover, an optimal bi-layer period was identified, resulting in optimal mechanical properties that were consistent with the high-temperature tribological properties. Furthermore, the wear tracks on the specimens were analyzed through field-emission scanning electron microscopy, which support the wearing behavior alteration. Finally, a CrMoN/SiN x multilayer coating with optimal high-temperature characteristics was demonstrated in this study.