Formation of Coatings from Accelerated Ions of Fluorinated Fullerene C60(CF3)12

Abstract

The first results of the deposition of coatings from accelerated ions of fluorinated fullerene C₆₀(CF₃)₁₂ are presented. The coatings are formed at room temperature on Si substrates from a beam of singly charged \({{{\text{C}}}_{{60}}}({\text{C}}{{{\text{F}}}_{3}})_{{12}}^{ + }\) ions with an energy of 5 keV, as well as from an ion beam that also contains doubly charged \({{{\text{C}}}_{{60}}}({\text{C}}{{{\text{F}}}_{3}})_{{12}}^{{2 + }}\) ions and a certain amount of ionized fragments of molecules. The properties and structure of coatings obtained from accelerated ions of fluorinated fullerene are compared with the properties and structure of coatings obtained from accelerated fullerene C₆₀ ions under the same conditions. According to X-ray photoelectron spectroscopy (XPS), fluorinated fullerene coatings contain about 4% fluorine. Investigations of the coatings structure and chemical bonds by X-ray photoelectron spectroscopy and Raman scattering show that the presence of fluorine leads to a decrease in the content of sp³-bonds in the coatings and the formation of graphite-like sp²-structures. Coating hardness (H) and Young’s modulus (E) compared to C₆₀ ion coatings decrease from 36 to 18 GPa and from 245 to 133 GPa, respectively, while the H/E ratio remains the same (~0.14). Tribological tests have shown for all coatings the friction coefficient is close to 0.1. All coatings are also characterized by a very low wear, less than 10^–7 mm³/(N m). For coatings obtained from C₆₀(CF₃)₁₂ ions, the contact angle is ~76°–78°. In the absence of fluorine, for the coating obtained from C₆₀ ions, it is ~90°.