Scientists of South Ural State University elaborated a unique technology for manufacture of products made of carbon graphite materials with high performance properties. The new technology will be applicable in ferrous and non-ferrous metallurgy, electric power industry and electrical engineering, chemistry, mechanical engineering, atom power engineering and rocket and space industry.
A group of scientists from South Ural State University (SUSU) – a university taking part in Project 5-100 – under the leadership of Marina Samodurova, Candidate of Sciences (Engineering), Associate Professor at the Department of Metal Forming of the SUSU Institute of Engineering and Technology, invented and patented a unique technology for manufacture of products made of carbon graphite materials with high performance properties. Such products have the largest range of application in electric transport and electrical engineering due to operating temperature of carbon graphite to be higher than 700°С. The research was carried out in cooperation with an industrial partner of SUSU – the Avers Company.
Carbon graphite materials are materials with high content of carbon (not less than 99% by mass) with mainly graphitic structure. As noted by experts, such materials possess a unique set of chemical, physical and mechanical properties which make them irreplaceable in ferrous and non-ferrous metallurgy, electric power industry and electrical engineering, chemistry, mechanical engineering, atom power engineering, and rocket and space industry.
“The invention is related to powder metallurgy, in particular, to manufacture of products for electrical equipment out of materials on the basis of graphite with a polymer binder. This material is a mixture of graphite powder and phenol formaldehyde resin powder. One of the areas for using this invention is contact stripes for urban transport, brushes for electric machines, urban and railway transport, etc,” explains Marina Samodurova.
The “standard” method of manufacture of products for electrical engineering purposes assumes preparation of a mixture out of graphite and a binder, and further press moulding of products out of it in a press mold heated till the temperature of 160-170°C. At this method, the mixture goes straight to the press mold right after it’s been prepared, which reduces density of obtained products and their physical and mechanical properties.
The technology developed by SUSU scientists allows increasing density of finished product, as prepared powdered composition gets seated for 4-6 hours under temperature of 70-90°С before pressing.
“Our inventions are related to the technology of manufacture of products out of carbon graphite materials with the method of pressing. Initially, carbon graphite materials are in the powdered form. Composition of the used material includes mixture of graphite with certain components. As we mainly work with products intended for electrical engineering, aside from graphite we also use a polymer binder which, under compacting and further thermal treatment, allows producing compact products of necessary geometric sizes with required properties,” says Marina Samodurova.
Also, the method proposed by the scientists allows solving the problem of sticking of liquid resin on matrix walls, as it provides the possibility to not only remove moisture and gases out of the mixture but also obtain a layer of several-micron thick polymer on solid particles of novolac resin (exclude their transformation into liquid under contact with heated walls of the press mould).
Another advantage of the technology developed at SUSU is low cost of production. The amount of wastes left after pressing does not exceed 2-5%. Besides, the technology requires less financial expenditures as it excludes the process of high-temperature annealing.
“Presently, products made of graphite with the use of this technology get supplied to practically all regions of Russian as well as to the CIS countries (Belarus, Kazakhstan, etc.),” says Marina Samoduriva. ”Industrial enterprises specialized on pressing of powdered materials are very interested in this invention. When buying the license, industrial enterprise can introduce this technology for manufacture of products for electrical engineering and products for construction purposes made of graphite.”
The patent obtained by SUSU scientists and entitled “Method for obtaining electrical engineering products out of powdered compositions based on carbon” is an important stage of a serious research work. Work with graphite is being done in other directions as well, because, graphite products and their application is one of the most prospective research areas, according to SUSU scientists who have been conducting research and patent works on introduction of novel and improvement of already existing technologies for manufacture of products made of carbon graphite materials for more than 5 years.