NEW METHODS AND TECHNOLOGIES FOR PROCESSING CARBON FIBER-REINFORCED PLASTICS

The article deals with the application of new methods and approaches for machining of carbon plastics on the basis of the analysis of foreign information sources with a search depth of five years. The complex problems of composite materials processing, in particular, carbon plastics, the solutions of which have not yet been found in full, are noted. Applying of new methods of hole formation, part milling, hydro-abrasive and laser processing allows to obtain new output quality indicators is pointed out. The implementation of considered methods, developed by foreign scientists, may supplement the tools arsenal and technologies of composite materials processing at domestic enterprise. The importance of quality assurance of composites` complex surfaces processing and formation in aircraft and aerospace engineering, where utilization level of this material is constantly increasing, is indicated.

New Technologies for Producing Multifunctional Reinforced Carbon Plastics

In this article we investigated properties of elementary carbon fibers after their activation and subsequent deposition of thin layers of metal coatings on their surface. For deposition we used copper, titanium and stainless steel. We investigated influence of various technologies of preliminary processing of the fiber surface on the value of the adhesion strength of the metal coating to the carbon tape and on the mechanical properties of elementary fibers. We established that the strength of carbon plastics at interlayer shear increases by 10-30% when using carbon tapes and fabrics with a metal coating.

Influence of the structure and thermomechanical properties of oriented carbon plastics on their tribotechnical characteristics

It has been established that carbon plastics are increasingly used in various industries as structural materials. By the set of their properties, carbon plastics outperform steel, cast iron, alloys of non-ferrous metals. However, the application of these materials for parts of machine friction units is still limited due to the difficult operating conditions of modern tribosystems. This work aims to conduct a comprehensive experimental study of the tribological properties of materials in the tribosystem "carbon plastic-metal" taking into consideration their structure, as well as the mechanical-thermal characteristics. Comparative tests of the dependence of the friction coefficient on load for metal and polymeric anti-friction materials have shown a decrease in the friction coefficient for plastics by 3...4 times (textolite, carbotextolite, and carbon-fiber plastics). The influence of the filler orientation relative to the slip plane on the anti-friction properties of carbon-fiber plastics was investigated; it was found that the direction of fiber reinforcement in parallel to the friction area ensures less carbon-fiber plastic wear. A linear dependence of the wear intensity of carbon-fiber plastics, reinforced with graphite fibers, on the heat capacity and energy intensity of the mated steel surface has been established. Based on the microstructural analysis, a layered mechanism of the surface destruction of carbon-fiber plastics was established caused by the rupture of bonds between the fiber parts, taking into consideration the direction of the fibers' location to the friction surface. The results reported here could provide practical recommendations in order to select the composition and structure of materials for the tribosystem "carbon-fiber plastic-metal" to be used in machine friction units based on the criterion of improved wear resistance

Influence of sliding bearing design on efficiency of the fluoroplast macromodifier for antifriction carbon plastics

The paper presents the results of laboratory and bench tests of UGET and FUT antifriction carbon plastics macro modified with PTFE. The efficiency (friction coefficient reduction) of this modification of carbon fiber reinforced plastics has been confirmed. The dependence of the method’s efficiency on the design of sliding friction units has been established. The plastic deformation of the fluoroplastic is the key factor that determines the effectiveness of the modifier when designing sliding bearings. The design of the friction unit should exclude the pressure gradient in the fluoroplastic protectors and prevent the possibility of an uncontrolled exit of the fluoroplastic from the friction zone.

Influence of the initial roughness of the antifriction carbons surface on tribotechnical characteristics and running-in coating efficiency

The roughness of the friction surface of antifriction carbons used in sliding friction units lubricated with water affects the tribotechnical characteristics during the running-in process. This article experimentally substantiates the range of optimal surface roughness formed during mechanical cutting of carbon plastics in terms of tribotechnical efficiency. The results of a series of tribotechnical tests using various methods under various conditions (contact pressure, sliding speed, counterbody materials) are presented. The relationship between the initial roughness and the effectiveness of a running-in coating based on FORUM® polytetrafluoroethylene powder is established.

CARBON AND GLASS REINFORCED POLYMER BASED ON SOLVENT-FREE BINDERS RESISTANCE TO THE IMPACT OF A MODERATE COLD AND MODERATE WARM CLIMATE

In this work has been investigated the climatic resistance of carbon and fiberglass polymers for aviation purposes based on solvent-free binders VST-1208, VSE-1212, VSR-3M after 3 years of exposure of these materials in the moderate cold climate of Moscow and the moderate warm climate of Gelendzhik. The effect of destruction, post curing, plasticization of binders on the compressive and flexural strengths of carbon plastics VKU-27L, VKU-39, VKU-46 and fiberglass plastics VPS-47/7781, VPS-48/778 was determined using the methods of profilometry, moisture transfer and dynamic mechanical analysis. It is shown that while determining the state of PCM after climatic exposure, it is necessary to take into account the effects of the reversible plasticizing action of moisture. A comparison is made of the climatic resistance of the investigated materials.

INFLUENCE OF ADDITIONAL SIZING OF CARBON FIBER IN PRODUCING VOLUME-REINFORCED PREFORMS ON THE PROPERTIES OF HIGH-TEMPERATURE CARBON FIBER

Presents the results of experimental studies of the effect of additional apparet on the properties of high-temperature carbon plastic based on a heat-resistant thermosetting phthalonitrile binder and a volume-reinforced woven preform. Comparative data are given on physical and mechanical properties of carbon plastics based on preforms with and without an apparet, including after exposure to operational factors (thermal aging, water and moisture absorption), results of thermal analysis and microstructure research.