A study was made of the cyclic strength of domestically produced oxide-carbide ceramics during the processing of hardened steel samples installed in the faceplate body under intermittent turning conditions. Turning was carried out until the destruction of the cutting edge of the plates. The structure of the destroyed surface layer is investigated and the mechanism of destruction of the cutting edge of tool plates made of cutting ceramics is determined. It has been established that the low performance of cutting inserts made of oxide-carbide ceramics under interrupted turning conditions is mainly caused by chipping of the cutting edge due to the formation of microcracks at grain boundaries. A characteristic feature of the brittle fracture mechanism of cutting ceramics is intergranular tearing and spalling of large grains AL 2 O 3
A ceramic brick was obtained on the basis of intershale clay and slag from burning brown coal without using traditional natural raw materials. Studies have shown that the ferrous compounds on the surface of the test samples (the oxidizing environment predominates) is mainly represented by hematite, and in the center (reducing environment) - magnetite. In this case, Fe 3+ is reduced to Fe 2+ and an early formation of a liquid phase occurs, which favors the occurrence of reactions of mullite formation, which determines the main physicomechanical parameters of ceramics. In the studied samples, there are mainly relatively large pores (up to 40 ?m) oval and pores of the type & # 171; channels & # 187;
The main methods of obtaining metal nitrides are considered. The main advantages and disadvantages are highlighted for each method. The possibilities of using these materials in various industries are briefly presented.
The effect of the synthesis temperature on the phase composition, size distribution and morphology of AlMgB 14 particles obtained by direct interaction of elemental Al, Mg and B powders with the addition of free carbon in a vacuum of 10-2 Pa at 1200 - 1400 & # 176 ; C. The synthesized powders were analyzed by X-ray diffraction, SEM, EDX, and laser diffraction. The highest mass content of the main phase AlMgB 14 (94 & # 37;) was obtained at a synthesis temperature of 1200 - 1300 & # 176; C and holding for 1 h. Impurities MgA l2 O 4 , as well as magnesium-depleted spinel and AlB 12 at holding temperatures above 1300 & # 176; C
The composition of the charge for facing ceramics based on low-plasticity clay with an additive containing boric acid and lithium carbonate as fluids, as well as titanium dioxide as a hardening additive has been developed. The influence of the applied additives on the formation of the structure, composition and main operational properties of the obtained ceramics
is investigated.
The process of the proposed technology for the formation of a transition layer between the dispersion medium and the dispersed phase of a ceramic matrix composite is investigated, and a technique for the manufacture of multilayer samples simulating at the macrolevel the phase boundary in the direction of the matrix - the core of the composite material is presented. A qualitative and semi-quantitative analysis of new phases, which are the product of interaction during the firing of a core from slime iron ore waste and a matrix from clay raw materials, is presented.
Polycrystalline diamond composites (PCD) were obtained by infiltration of cobalt from a hard-alloy substrate into a porous diamond layer at a temperature of 1600 ° C and a pressure of 6.0 GPa in a cubic compression press. In order to improve the thermal stability of the composite, the top layer of cobalt was etched with hydrofluoric acid to a depth of 150 ?m. Transmission electron microscopy (TEM) was used to analyze the interaction at the grain-bond and grain-grain interface. After the infiltration of cobalt at the grain boundaries, the grain binder contains phases of nanodiamond and cubic cobalt carbide C o C x , while after etching of cobalt in the surface layer of a sintered polycrystalline diamond composite zita found bulbous structures
A review of publications devoted to additive technologies used in the production of ceramic products is presented. Methods for molding articles from sedimentation-resistant systems are described in most detail. The advantages and disadvantages of each method, as well as their characteristics are given. Reflects the basic requirements for the parameters of print media
The paper presents the results of a study by the methods of mechanoluminescence (ML) and acoustic emission (AE) of the response of ceramic materials ZnS and ZnSe to impact damage to the surface. The experiment simulates the process of dust erosion of optical elements made of these materials, installed on high-speed mobile carriers. A comparison of the time series of light and sound emission showed that the ML exhibits two peaks approximately 50 - 100 and 150 - 200 ?s after the impact, while the AE generation occurs with a single maximum in the region of 200 ?s. The result is explained by the plastic deformation of the material at the first stage of fracture and the subsequent formation of microcracks.
The results of the synthesis and analysis of diamond microcrystals with a high degree of boron doping (& # 8776; 2 & # 37;), which were obtained from mixtures of gas soot with M-carborane at 8 GPa and 1873 K, are presented. The high concentration of boron in the diamond lattice is confirmed by X-ray data and characteristic Raman spectra, which correspond to diamonds with metallic conductivity. Thermobaric treatment of the diamond-like dl-BC 3 phase (1100 K, 25 GPa) leads to the formation of BC 3 -heteronano-diamond
