Department of Technical Ceramics
Head of the Department: Gennady Ya.Akimov,
candidate of physico-mathematical sciences
Directions of Scientific Researches: Development of fundamental bases of manufacturing methods of nano-crystalline ceramic materials. Experimental elaboration and manufacture of nano-crystalline oxide ceramics. Investigation of physico-mechanical and electro-physical properties of ceramics on the base of zirconia dioxide. Elaboration of principles of controlling the ceramics properties and ways of article shape-formation of the ceramics.
It has been found that cold isostatic sealing (CIS) of nano-crystalline powders of a partially yttrium-stabilized zirconium (PYSZ) causes a martensite transformation of a tetragonal phase into a monocline one.
It has been shown that the CIS of nano-crystalline powders significantly decreases the temperature of the PYSZ-ceramics sintering at a simultaneous improvement of its physico-mechanical characteristics. The nano-crystalline ceramics obtained with the use of this effect possesses a very high complex of physico-mechanical properties, namely, density - 5,98 g/cm3 (99% of a theoretical one), strength during a three-point bend test - 1500 MPa, crack stability 18 MPa·m1/2, an average grain size 200nm. It has been found that the PYSZ-ceramics strength is determined not by a grain size and density but by a degree of tetragonality of the tetragonal phase localized on the surface of the sample under test. The larger the degree of tetragonality of a tetragonal phase, the higher the material strength.
It has been shown that the completeness of a mechanically activated martensite transformation of a PYSZ-ceramics is considerably dependent on the time of a mechanical load action. It has been found that a high hydrostatic pressure essentially decreases the completeness of a mechanically activated martensite transformation of a tetragonal phase into a monocline one. It has been shown that this effect is conditioned by a transformation challenge as it proceeds with a volume increase by 9%.
Temperature and frequency dependent peaks of a low-frequency internal friction in a PYSZ-ceramics in the temperature range from 273 to 373 K were first detected as conditioned by the stress relaxation on the boundaries of twins and domains.
There has been experimentally detected the Gorsky effect manifestation (a rising diffusion of point defects in the stress field) in the ionic conductivity of a solid electrolyte on the base of a completely stabilized ZrO2.
Development of a laboratory technology of manufacturing of ceramic articles from nano-crystalline oxide powders using cold isostatic sealing (CIS). With the use of this technology there have manufactured 500 technical knives from the PYSZ-ceramics to order of the firm CERATEC technical ceramics BV (the Netherlands), and to order of the SPO ETALON (Ukraine) 450 plain bearings for the machines of the firm ATOMAT (Italy) and HERKULES (Germany).
There is also developed the technology of manufacturing the PYSZ-ceramics ball elements for artificial limbs of a hu-man being hip joints and ceramic scalpels.
There has been obtained a Y- PYSZ-based material with a high thermal stability required for high-temperature oxygen sensors of a nonconsumable use and other longterm solid electrolytes.
The Institutes of the NAS of Ukraine: the Institute of Materials Science Problems, the Institute of CM, the Institute of đđ), Donetsk State Chemical-Technological University (the Ministry of Education and Science), ÷įįíë (the Ministry of Industrial Politics of Ukraine).
1. G.Ya.Akimov, V.M.Timchenko, I.V.Gorelik, Peculiarities of phase transformations in a fine-dispersive zirkonia dioxide deformed by a high hydrostatic pressure. Fizika tverdogo tela 36 (12), 3582 (1994).
2. G.Ya.Akimov. Phenomenon of self-deformation under a hydro-stati compression of powders consisting of ion-covalent mono-crystals of a submicron size. Fizika tverdogo tela 38 (2), 654 (1996).
3. G.Ya.Akimov, V.I.Barbashov. Peculiarities of a hydrostatically compressed zirconia dioxide failure. Fizika tverdogo tela 38 (6), 1820 (1996).
4. G.Ya.Akimov, V.M.Timchenko. Influence of a loading rate on mechanical properties of the polycrystalline solid solution ZrO2 3 mol % Y2O3. Fizika tverdogo tela 39, 880 (1997).
5. G.Ya.Akimov. Cold isostatic sealing as a way of manufacturing ceramic articles with a high level of physico-mechanical properties. Ogneupory I tehnicheskaya keramika 8, 21 (1998).
6. G.Ya.Akimov, V.M.Timchenko. Influence of the deformation and preliminary loading rate on the ZrO2-based ceramics crack resistance. Problemy prochnosti 5, 123 (2002).
7. G.A. Marinin, V.N.Varyukhin, O.N.Potapskaya. Low-Frequency Internal Friction of Policrystalline ZrO2+ 4mol%Y2O3 in the temperature Range. Physics of the Solid State 44 (7), 1323 (2002).
8. G.Ya.Akimov,G.A.Marinin,V.Yu.Kameneva. Evolution of a phase composition and physico-mechanical properties of ceramics ZrO2 + 4mol%Y2O3. FTT 2 (46), 250 (2204).
9. V.I.Barbashov, Yu.A.Komysa. Mechano-electrical effect in solid electrolytes. FTT 2 (47), 229 (2005).