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PACS 61. 78.40.Fy The comparative analysis of the results obtained in the investigation of infrared absorption spectra of irradiated lithium fluoride and magnesium oxide samples has been made. For irradiation of the samples X-ray generator, Co 60 source and different reactors were used . The universal linear dependence of bands caused by centers containing OH -ions was observed for the first time in the irradiated MgO samples.. The thermal treatment of irradiated LiF crystals have clearly showed the interconnection of hydroxyl ions and hydrogen products of their dissociation.The significant difference in the behaviour of impurity hydroxyl ions in matrices of the mentioned ionic compounds was observed.

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The high‐temperature thermally stimulated luminescence (TSL) of nominally pure MgO crystals and MgO crystals with excessive amounts of paramagnetic manganese and vanadium ions irradiated in a reactor has been studied. It was observed that the influence of impurity on the TSL of crystal is different at low and relatively high doses. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

B 4 C and B 4 C-ZrB 2 (Zr-3-5 wt.%) ceramic materials were obtained by the method of hot pressing at temperature range 2,050-2,140 °C and 34-40 MPa pressure, and subject to further thermal treatment at 1,800 °C. Physical and mechanical properties of the above composite, the effect of ZrB 2 on the process parameters of items formation and on the obtained composite features were studied. Relatively perfect microstructure and optimum physical and mechanical properties are characteristic for B 4 C-3.7% ZrB 2 ceramics, the relative density of which equals 100%. Compared to B 4 C, it demonstrated 10% reduced average grain size and 8% higher fracture toughness; Reduced linear thermal expansion coefficient and mechanical bending strength and doubled thermal conductivity at high temperatures; Increased Young modulus, hardness and compressive strength, which make 363 MPa; 30.1 GPa and 3,175 MPa, respectively. When alloying phase (ZrB 2) content increased to 6.2 wt.%, average grain size growth to 8 μm, fracture toughness, microhardness and mechanical bending strength decreased and made approximately 2.37 MPa√m, 28.2 GPa and 292 MPa, respectively.