Study on structure, mechanical and tribological properties of iron incorporated diamond-like carbon films

In current paper, iron incorporated diamond-like carbon films were deposited successfully via direct current reactive magnetron sputtering process at different methane flow rates. The morphologies, structures and phases of the Fe-DLC films were studied by field-emission scanning electron microscopy, X-ray photoelectron spectra, X-ray diffraction and Raman spectroscopy, and their mechanical properties were investigated using nanoindentation tester and scratch tester. In particular, the friction and wear behaviors of as-deposited films were evaluated both in the ambient air and deionized water conditions via reciprocating sliding tribometer. It revealed that Fe3C nanocrystallines were generated, and appropriate content of Fe3C nanocrystallines in the amorphous carbon matrix could improve the hardness and adhesion strength of the films. As a result, the iron incorporated diamond-like carbon film deposited at methane flow rate of 18 sccm could possess relatively higher hardness of 14.4 GPa, elastic modulus of 134.7 GPa and best adhesion strength with critical load of 38 N. Especially, it presented superior friction and wear performances both in ambient air and deionized water conditions. In comparison with as-deposited films tested in ambient air condition, each sample exhibited more excellent tribological performances with lower friction coefficient and wear rate in deionized water condition.