The XPS method was used to study the composition of the surface of carbon fibers after modification in a low-temperature plasma in an octafluorocyclobutane medium. It has been shown that ionic and semi-ionic fluorine bonds are formed on the surface of carbon fibers at the initial stages of treatment (30–60 s), and, then, a coating is formed that is similar in composition to polytetrafluoroethylene, but is characterized by a branched structure and the content of oxygen groups. The influence of the initial state of the surface of carbon fibers, namely, preliminary oxidation, on the composition of the formed fluoropolymer coating has been studied.

This paper reports on studies of tribotechnical behavior under conditions of friction without lubrication and the mechanical properties of fluoroplastic composites with discrete carbon fibers obtained from different grades of fluoroplastic-4 (F-4, PTFE). The particle size of PTFE powder and its mechanical properties influence the tribotechnical properties of composites with carbon fibers. The wear resistance and PV factor are higher and the friction coefficient is lower for the composite based on F-4 grade PN 90, whose powder particles are larger than the PTFE particles of the other studied grades. Composite made of modified fine-particle PTFE (grade TFM 1705) showed the highest modulus of elasticity and strength. It is assumed that large PTFE particles, which affect the mechanical properties of the composite negatively, contribute to a more intense formation of a transfer film during friction, and also reduce the contact area, which reduces the friction coefficient with increasing pressure in the friction zone.

One of the important tasks of the technology of surface treatment by plasma techniques is modification of sophisticatedly shaped items containing surface areas that are not directly accessible to the modifier. Gaseous organofluorine compounds are known to be used for plasma treatment of fibrous carbon fillers to improve the adhesive interaction with a binder [1]. However, the mechanism and results of the action of plasma of f luorinated gases on the surface of fibrous carbon materials, which are porous electrically conductive systems, have not been studied to a sufficient extent. One of the urgent problems is to increase the efficiency of processing the inner surfaces of fibrous– porous materials. The theoretical foundations of the treatment of hard-to-reach surfaces in relation to the synthesis of thin-layer coatings on them from the gas phase were initially developed in [2–5]. Theoretical conclusions were confirmed in experiments with the synthesis of poly-p-xylylene [2, 3, 6–9]. The aim of this work is to elucidate the main features of the formation of polymer coatings on hard-toreach surfaces for gaseous media in a narrow cavity during deposition from a glow discharge in an octafluorocyclobutane (C4F8 cycle, OFCB) medium. Experiments on the study of the effect of OFCB plasma on half-open surfaces, including the plasma with small admixtures of atmospheric gases, were carried out in a cylindrical chamber with parallel plate electrodes. The inhomogeneity of the thickness of the coating synthesized from the products of plasma-chemical transformations of OFCB on the surfaces of sensors placed in a narrow cavity in the absence of direct exposure to plasma was studied. Plasma-activated products could enter the cavity only from one side. The dimensions of the cavity formed by two polished plates fixed in parallel with a gap of 3 mm were 125 × 84 mm. One of the lateral sides of the cavity is open to the outside, and the other three are muffled and sealed to prevent uncontrolled penetration of plasma components. Quartz resonators with an open disk crystal of 8 mm in diameter were placed inside the cavity, serving as sensors for coating deposition or etching. The sensors were placed in two rows along both sides (side walls of the cavity): near the open side, in the middle of the gap, and near the plugged end at distances of 12, 56, and 106 mm from the open side of the gap. The layout of the cavity with installed sensors is shown in Fig. 1.