Siberian Federal University (Krasnoyarsk, Ruissia):

T. R. Gilmanshina, Cand Eng., Associate Prof., e-mail: gtr1977@mail.ru
N. S. Perfilyeva, Cand Eng., Associate Prof.

I. N. Ulyanov Chuvash State University (Cheboksary, Russia):
I. E. Illarionov, Dr. Eng., Prof, Head of the Dept. “Materials science and metallurgical processes”, e-mail: tmilp@rambler.ru
E. N. Zhirkov, Post-graduate, Dept. “Materials science and metallurgical processes”

The aim of this work is to study the eff ect of graphite activation time with various types of surface-active materials (carboxymethyl cellulose, technical lignosulfonate, synthetic detergent, liquid glass, ethyl silicate and water) on the properties of aqueous graphite-bentonite coatings. Activation of graphite with surfactants was carried out in a planetarycentrifugal mill AGO-2. Density, sedimentation stability (after 3 hours), reduced strength was controlled in accordance with GOST 10772-78, viscosity -measuredby viscometer VZ-4, — in accordance to GOST 8420-74. The thickness of the cover and penetrating layers was determined using a microscope OBSERVER.D1m from CarlZeiss. It is shown that the most optimal level of properties in comparison with the standard non-stick coating is achieved with the activation of graphite in a planetary-centrifugal mill AGO-2 for 20 min with carboxymethyl cellulose and technical lignosulfonate (the surfactant content is 1% by weight of graphite ): the sedimentation resistance of the developed coatings is 1.2 times higher, the reduced coating strength is higher by more than 10 times, the viscosity is 7.0–7.5 times, and the consumption of dry components is reduced by 30-40%. The thickness of the coating layer is reduced by 1.2 times, and the penetrating layer is increased by 7 times, which will help to further strengthen the surface layers of the mold and prevent their destruction during pouring of the metal.

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