It is possible to monitor the quality of graphitized carbon components by measuring the electrophysical properties, which is demonstrated from experimental studies on the relation between the thermo-EMFs of carbon fibers in relation to the normal elasticity modulus for a particular type of high-modulus carbon fiber. It is shown that current devices can be used to measure the properties in making carbon items with continuous recording of the monitoring results.Graphitized carbon materials are used in heating and other forms of equipment, and their quality is subject to fairly stringent requirements. Nondestructive test methods can be employed in their production to provide prompt monitoring not only during production but also during use.A basic quality criterion for a graphitized material is provided by the physicomechanical properties. To evaluate those, standard methods based on manufacture and subsequent testing of special specimens may also be accompanied by nondestructive methods such as ultrasonic ones (instruments of the type of Pulsar and UK-10PM), as well as methods based on natural frequencies of the items (instruments of Zvuk, IChSK, and other types) [1]. When one determines those properties of high-modulus carbon fibers, one can also use an ultrasonic method (instruments of UIMU type).The properties of graphitized materials can also be judged from the electrophysical parameters, since those properties are substantially influenced by the structural characteristics. Tests have been done on the correlations between structure, physicomechanical properties and electrophysical properties, which show that it is possible to evaluate the physicomechanical properties and the quality not only by direct measurement of those properties but also by measuring the electrophysical ones. These data are based on researches by S. V. Shulepov, A. I. Lutkov, R. M. Levit, A. A. Konkin, V. Ya. Varshavskii, and various other researchers [2 -13].A carbon-base material may have conductivity of metal type or semiconductor type. Also, the anisotropy in the properties of graphite substantially influences the electrical conductivity. The electrical conductivity varies very widely in solids. The bulk specific resistivity is 10 5 -10 6 W × m for insulators, while for full conductors it is less than 10 -6 W × m. This means that electrophysical methods can be applied to researching and monitoring graphitized carbon materials.We consider that the most promising methods for monitoring graphitized materials are the electromagnetic one (eddy currents), and the thermoelectric and electrical-capacity ones. In the mid-1960s, the Soviet Union had developed and routinely produced several types of electrical conductivity meter, including the IE-20 for measuring the electrical conductivity of graphite components by means of eddy currents [2]. Similar instruments were produced and are being produced by foreign firms, but there has been no general use of such instruments in Russian industry up to the present. Most often, Russian industry employs ins...

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The possibility of using a small VIMS-1 device for measuring the electrophysical properties of abrasive molding pastes made of micropowders in developing formulas for an abrasive tool and for controlling the quality of the pastes in production conditions was examined. It was shown that introduction of control of the electrophysical properties of molding pastes is a real possibility for obtaining molding pastes of stable quality.The manufacturing process in production of an abrasive tool made of silicon carbide and electrocorundum micropowders in a ceramic binder is very complex and the requirements dictated by metalworking conditions for the quality and stability of these articles are high. It is possible to improve product quality by raising the level of quality control of conducting the manufacturing process and the costs of mastering new methods of control of the initial raw material and respecting the conditions of the manufacturing process are almost always quickly recovered by decreasing rejects and the stability of product quality.Based on research on production technology for abrasive articles and ceramic articles with similar properties molded by semidry molding, it is possible to truly say that the properties of the raw materials and molding pastes are the most important factors that affect the final properties of abrasive articles made from micropowders.A comparative analysis of silicon carbide micropowders from different manufacturers and the articles made from them revealed the following. Silicon carbide micropowders can satisfy the requirements of the manufacturing conditions with respect to the chemical composition and impurity content and still (within the framework of the same grain size) differ significantly in granulometric composition [1]. The observed differences in the granulometric composition of micropowders affect the character of the behavior of the silicon carbide grains in firing. For this reason, such parameters of the standard manufacturing process as the content of components and tool firing conditions must be corrected. This is because the resistance to heating (oxidation) of silicon carbide grains is a function of their size, while the amount of silicon oxide grains formed on the surface affects the overall structure and density of the articles and the cutting properties of the tool. Introduction of input control of the grain composition of the micropowders and conducting the manufacturing process in accordance with the granulometric composition of the silicon carbide are mandatory conditions for stable tool quality.The results of studying molding pastes for an abrasive tool made of electrocorundum and silicon carbide micropowders in a ceramic binder are reported here. The abrasive molding pastes consist of an abrasive material, a ceramic binder containing clay and feldspar, water, and a temporary binder -dextrin. Molding pastes acquire the required structural and mechanical properties during mixing, wetting with water, and ripening. The ratio of the basic components in the paste,...

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