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.

Experimental works have been conducted the objective of which was to improve mechanical properties of boron carbide by introduction of doping elements into the system. Titanium and Zirconium were selected as doping elements, which were introduced into the system in the form of TiB 2 and ZrB 2. Four types of boron carbide-titanium and zirconium mixture with various titanium and zirconium diboride content were used in experiments. Optimal process parameters, as well as doping elements concentration, necessary to provide required high mechanical parameters in the composite were defined.

Composites were obtained in the in SiC-SiAlON and Al 2 O 3 -SiAlON system. Physical-chemical processes going on at the obtaining of SiALON within the range of 800˚C -1500˚C were studied. Charge compositions and sintering regime were selected. It was proved that X-SiALON was obtained at the sintering of kaolin-aluminum powder at 1500˚C, while β-SiALON was formed at the sintering of SiC-Aluminum powder, silicium and Al 2 O 3 -aluminum powder, silicium at 1500˚C. Corrosion properties of the materials were studied. Investigations were performed by the methods of X-Ray structural and microscopical analysis.

Boron carbide is known as a hard material; it possesses a unique complex of physical-mechanical properties and has diverse applications in industries. An expansion of its field of uses stems from the creation of boron carbide matrix nanocomposite materials. In view of this perspective, an effective liquid-charge synthesizing method for their components in nanopowder form has been proposed. This paper provides a focused review on advanced boron carbide matrix ceramic and metal-ceramic nanocomposites recently obtained by the authors using this method. Particular attention is paid to the characterization of boron carbide nanocomposites, including some ceramic borides, metallic alloys and also other metal-ceramic composites.

Goal: obtaining of composite in the SiC-SiAlON system with the metal thermal method in the nitrogen medium. Method: SiALON-s are solid metal oxide solutions in nitrides. Area of their presence is considered in four-component system-Si 3 N 4-ALN-AL 2 O 3-SiO 2. In the present paper SiA-LON-containing composite was obtained through alum-thermal process in the nitrogen medium on the base of Geopolymer (kaolin and pologycley-Ukraine), SiC, aluminum nano-powder and Si powder with small additives of perlite (Aragatz, Armenia) by the reactive baking method. The advantage of this method is that compounds, which are newly formed thanks to interaction going on at thermal treatment: Si 3 N 4 , Si, AlN are active, which contributes to SiALON formation at relatively low temperature, at 1250˚C-1300˚C. Results-ß-SiAlON was formed at the sintering of SiC-aluminium and silicium powder, geopolymer at 1450˚C. Porosity of carbide SiAlON composite obtained by reactive sintering, according to water absorption, equals to 13%-15%. The samples were fragmented in a jaw-crusher and were powdered in attrition mill till micro-powder dispersion was obtained. Then samples were hot-pressed at 1620˚C under 30 MPa pressure. Hold-time at the final temperature was 8 min. Sample water absorption, according to porosity, was less than 0.4%. Further studies were continued on these samples. Conclusion: the paper offers processes of formation of SiC-SiAlON composites and their physical and technical properties. Phase composition of the composites was studied by X-ray diffraction method, while the structure was studied by the use of optic and electron microscope. Electric properties showed that the specimen A obtained by hot-compression is characterized by 2 signs lower resistance than the porous material B, which was used to receive this specimen.