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The development of modern jet engines would not be possible without dynamically developed nickel–chromium-based superalloys, such as INCONEL® The effective abrasive machining of above materials brings with it many problems and challenges, such as intensive clogging of the grinding wheel active surface (GWAS). This extremely unfavorable effect causes a reduction in the cutting ability of the abrasive tool as well as increase to grinding forces and friction in the whole process. The authors of this work demonstrate that introduction of a synthetic organosilicon polymer-based impregnating substance to the GWAS can significantly improve the effects of carrying out the abrasive process of hard-to-cut materials. Experimental studies were carried out on a set of a silicon-treated small-sized sol–gel alumina 1-35×10×10-SG/F46G10VTO grinding wheels. The set contained abrasive tools after the internal cylindrical grinding process of INCONEL® alloy 600 rings and reference abrasive tools. The condition of the GWAS after the impregnation process was studied, including imaging and measurements of its microgeometry using confocal laser scanning microscopy (CLSM), microanalysis of its elemental distribution using energy dispersive X-ray fluorescence (EDXRF), and the influence of impregnation process on the grinding temperature using infrared thermography (IRT). The obtained results confirmed the correctness of introduction of the impregnating substance into the grinding wheel structure, and it was possible to obtain an abrasive tool with a recommended characteristic. The main favorable features of treated grinding wheel concerning the reduction of adhesion between the GWAS and grinding process products (limitation of the clogging phenomenon) as well as reduction of friction in the grinding process, which has a positive effect on the thermal conditions in the grinding zone.

The age of synthetic diamonds began with the construction of the equilibrium phase diagrams of carbon. In 1939, O. I. Leipunskii [1] proposed a method for the thermodynamic calculation of the pressure dependence of the temperature of graphite-diamond equilibrium (G ~ D). Later investigations (calculations [2][3][4] and experiments in the temperature range 1500-2700 K [5]) largely substantiated and somewhat refined the data in [1]. The conditions of melting of carbon were determined, and it was proposed that metallic carbon exists at pressures above 60 GPa. The current form of the P-T phase diagram is shown in Fig. I. The thermodynamically stable form of carbon at atmospheric pressure is graphite. However, diamond can exist for a nearly unlimited time at room temperature or lower. Its graphitization begins at 1300-2100 K. Nor does graphite change into diamond with an increase in pressure to the values characteristic of the region of thermodynamic stability of diamond. A pressure considerably greater than the equilibrium pressure is needed for the G --* D transformation. Also, the lower the temperature, the greater the amount by which the equilibrium pressure must be exceeded in order to realize this transformation [7].The work of O. I. Leipunskii foreshadowed all presently known methods of producing diamond: the direct G --, D transformation in the solid state (conditions far from equilibrium, deep within the region of stability of diamond, at very high temperatures and pressures); recrystallization through the liquid or gas phase in the region of stability of diamond, but near the boundaries of the P-and T-equilibrium states; epitaxial growth on a diamond substrate in the region of thermodynamic stability of graphite. Industry employs recrystallization through a liquid --an equilibrium metallic melt that is thermodynamically stable. Recrystallization through a metastable melt is also possible, but this process is nearly uncontrollable, forms only small diamonds, and forms these diamonds only in a mixture with carbides that are simultaneously crystallized from the metastable melt [8]. The yield of diamond relative to the initial quantity of graphite is very low.The direct G --, D transformation requires a pressure on the order of 12 GPa and a temperature of about 3000 K. Diamond can be produced at considerably lower temperatures in the presence of certain metals, mainly metals belonging to the iron and platinum groups. Figure 2 shows the P-T region in which diamond is formed in the presence of different metals. The D ~ G equilibrium line is shown for comparison. Figure 3 shows the melting points of the metals, equilibrium carbon-bearing eutectics or peritectics in alloys of these metals with carbon, and metastable eutectics formed by contact of the same metals with carbon. The figure also shows the lowest temperatures at which diamond forms from graphite in the presence of the given metals.Such diamond-synthesis parameters as pressure and temperature can be determined only within the region in which a stable liqu...

Diamond crystallization in the Al-C system under high static pressure and temperatures has been investigated and diamond synthesis regularities have been established. Phase equilibria in the binary Al-C system at a pressure of 8 GPa have been studied using metallographic and X-ray diffraction analyses as well X-ray spectrum microanalysis. The samples were prepared by quenching. The experimental results have been used to define the unknown parameters in phenomenological models of the phases that compete at high pressures. The phase diagram of the Al-C system has been thermodynamically calculated and constructed at 8 GPa. It has been found that at a pressure of 8 GPa the incongruent mode of the melting of the Al 4 C 3 carbide is retained and between 2470 and 2800 K the L + D two-phase region appears in the phase diagram.

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