Boris Khina - Academia.edu (original) (raw)
Papers by Boris Khina
Metals, 2022
In this work, high chromium cast irons (HCCIs) reinforced by TiC particles are designed and fabri... more In this work, high chromium cast irons (HCCIs) reinforced by TiC particles are designed and fabricated to improve the erosion–corrosion and wear resistances of materials for the pumping and handling applications. The TiC particles are formed by the in situ solidification method. The experimental results show that the hardness of as-cast HCCIs is improved significantly with TiC volume fraction. It can be as high as 63 HRC when the TiC volume fraction is 9.8%. The introduction of TiC increases the abrasive wear resistance of the HCCIs in both as-cast and heat-treated states. However, it is unexpected to find that the presence of TiC significantly reduces the erosion–corrosion performance. It suggests that corrosion-enhanced erosion is the dominant mechanism that controls the mass loss of the TiC-strengthened HCCIs.
Вестник Белорусско-Российского университета, 2012
The institutions in Belorussia, which are involved in scientific research and development in the ... more The institutions in Belorussia, which are involved in scientific research and development in the area of SHS, are listed and their main achievements are outlined. The directions of research include theoretical and experimental investigation of filtration combustion, thermodynamic modeling of SHS, development of models of phase and structure formation mechanisms, theoretical and experimental study of mechanically activated SHS, and experimental investigation of SHS in an ultrasound field.
The effects of the application of ultrasound field (USF) on the combustion velocity and temperatu... more The effects of the application of ultrasound field (USF) on the combustion velocity and temperature during SHS as well as on the microstructure of the final product are described. The influence of USF on SHS is connected with a thermal factor (forced convection of ambient gas) and nonthermal, or physical factor. The latter is due to changes in the capillary spreading of a transient melt and nucleation conditions of solid products in the SHS wave. For the Ti-C-Ni-MO system, an optimal amplitude of ultrasound exists at which the uniformity of grain size of titanium carbide is substantially improved.
Technical Transactions, 2021
The kinetics of and mechanism for galvanising low-carbon steel (0.2% C) were examined in powder m... more The kinetics of and mechanism for galvanising low-carbon steel (0.2% C) were examined in powder media which were pre-treated to obtain a fine nanostructured ZnO layer on the surface of zinc powder particles. The effective diffusion coefficient of Zn atoms through the ZnO shell was estimated to be in the order of 1·10−10 m2·s−1. The contribution of the Zn-gas evaporation/condensation microprocesses, which could occur in relation to the above diffusion through a nanostructured surface layer, was evaluated with numerical calculations in the temperature range of 550–950 K and for an average particle size of ZnO up to 100 nm. Our results suggest that the outward diffusion of metallic zinc takes place from the core of powder microparticles across the nano-grain boundaries of their modified surface layer, and can be further intensified by the presence of other inter-phase defects, such as nano-porosity.
The effect of capillary titanium spreading was found on carbon grains during the synthesis of tit... more The effect of capillary titanium spreading was found on carbon grains during the synthesis of titanium carbide. The combustion rate of the Ti-C-Ni and Ti-C-Ni-Mo systems, including the low-melting inert component, was studied versus the parameters of the ultrasonic field. Adding a copper melt to the initial mixture with the limiting wetting angle θ > 90° enhanced the effect of the ultrasonic field on the combustion rate. The phenomena of acoustic emission during SHS were also studied. The spatial acoustic emission area was shown to be localized near the combustion wave.
Wear, 1993
Abstract The effect of a carburizing regime and subsequent heat treatment on the wear resistance ... more Abstract The effect of a carburizing regime and subsequent heat treatment on the wear resistance of high chromium steels is estimated. Carburization raises the abrasive wear resistance and allows significant suppression of the adhesion phenomena under dry sliding. The results obtained allow us to determine the regime of surface hardening of high chromium steels required to produce the desired combination of wear resistance and bulk strength properties.
Doklady Physical Chemistry
International Journal of Self-Propagating High-Temperature Synthesis
A case of combustion in a heterogeneous random medium is considered when the characteristic scale... more A case of combustion in a heterogeneous random medium is considered when the characteristic scales of combustion wave are less than the sizes of structural elements of the reacting system. In this case, a rigid percolation combustion regime is possible, in which the process has a form of successive ignition and burning of connected reactive particles constituting a cluster spanning the opposite boundaries of the system. Gasless 2D systems were modeled. Prototypes for such a model are mechanically activated powder mixtures for the synthesis of intermetallic compounds (e.g., Ni-Al, Fe-Al, Ni-Ti, etc.) diluted with an inert component. Estimations and numerical modeling have shown that percolation regimes are possible if the following conditions are satisfied: (i) each particle can burn independently, I.e., the ratio of the combustion zone scale to the particle size is less than unity and the heat exchange between particles is hampered; (ii) the heat losses are close to the extinction l...
We have performed thermodynamic modeling of the reduction of iron scale (production waste of meta... more We have performed thermodynamic modeling of the reduction of iron scale (production waste of metallurgy and machine-building) by products of incomplete conversion of methane in oxygen for developing a process of obtaining iron powder with the use of a plasma jet. We have calculated the equilibrium composition of the gas phase and condensed interaction products at various temperatures and initial compositions of the reducing medium. The optimal process parameters providing reduction of scale to pure iron, i.e., the temperature range, the methane/oxygen ratio in the gaseous medium, and the scale/gas mixture mass ratio, have been determined.
Materials Science Forum, 1994
Journal of Engineering Physics, 1988
Journal of Engineering Physics, 1988
A macrokinetic description is presented for diffusion produced by a solidphase reaction in a bina... more A macrokinetic description is presented for diffusion produced by a solidphase reaction in a binary system. The kinetics of processes on the interphase boundary and diffusion with the phase volumes are considered. The effect of kinetic factors on the growth of intermetallic compounds is studied numerically.
Journal of Engineering Physics, 1990
Soviet Powder Metallurgy and Metal Ceramics, 1991
The use of boron carbide for producing wear-resisting powder composites based on iron requires ex... more The use of boron carbide for producing wear-resisting powder composites based on iron requires examination of the processes of structure formation during sintering of these materials. It has been shown that gas-transport processes in the Fe-C-B system at T _< 1000~ lead to breakdown of B4C particles and formation of a layer of iron boricles on the internal
Physical Review B, 1991
The analysis of experimental data on compound formation during annealing of thin-film and bulk di... more The analysis of experimental data on compound formation during annealing of thin-film and bulk diffusion couples reveals the influence of interface reactions on phase-layer growth kinetics. Based on the mechanism of phase changes during interdiffusion, allowing for the diffusion through the vacancies in the bulk as well as atom travel across the interface and lattice transformations, a model for a
Physical Review E, 1993
The relationship between the stochastic and deterministic approaches to the description of the dy... more The relationship between the stochastic and deterministic approaches to the description of the dynamic behavior for a nonlinear reacting system is studied. A self-propagating exothermal reaction in a heterogeneous medium has been chosen as an example. A stochastic model for this phenomenon is developed. The system is composed of cells characterized by temperature and degree of conversion, their transformation probability
Metals, 2022
In this work, high chromium cast irons (HCCIs) reinforced by TiC particles are designed and fabri... more In this work, high chromium cast irons (HCCIs) reinforced by TiC particles are designed and fabricated to improve the erosion–corrosion and wear resistances of materials for the pumping and handling applications. The TiC particles are formed by the in situ solidification method. The experimental results show that the hardness of as-cast HCCIs is improved significantly with TiC volume fraction. It can be as high as 63 HRC when the TiC volume fraction is 9.8%. The introduction of TiC increases the abrasive wear resistance of the HCCIs in both as-cast and heat-treated states. However, it is unexpected to find that the presence of TiC significantly reduces the erosion–corrosion performance. It suggests that corrosion-enhanced erosion is the dominant mechanism that controls the mass loss of the TiC-strengthened HCCIs.
Вестник Белорусско-Российского университета, 2012
The institutions in Belorussia, which are involved in scientific research and development in the ... more The institutions in Belorussia, which are involved in scientific research and development in the area of SHS, are listed and their main achievements are outlined. The directions of research include theoretical and experimental investigation of filtration combustion, thermodynamic modeling of SHS, development of models of phase and structure formation mechanisms, theoretical and experimental study of mechanically activated SHS, and experimental investigation of SHS in an ultrasound field.
The effects of the application of ultrasound field (USF) on the combustion velocity and temperatu... more The effects of the application of ultrasound field (USF) on the combustion velocity and temperature during SHS as well as on the microstructure of the final product are described. The influence of USF on SHS is connected with a thermal factor (forced convection of ambient gas) and nonthermal, or physical factor. The latter is due to changes in the capillary spreading of a transient melt and nucleation conditions of solid products in the SHS wave. For the Ti-C-Ni-MO system, an optimal amplitude of ultrasound exists at which the uniformity of grain size of titanium carbide is substantially improved.
Technical Transactions, 2021
The kinetics of and mechanism for galvanising low-carbon steel (0.2% C) were examined in powder m... more The kinetics of and mechanism for galvanising low-carbon steel (0.2% C) were examined in powder media which were pre-treated to obtain a fine nanostructured ZnO layer on the surface of zinc powder particles. The effective diffusion coefficient of Zn atoms through the ZnO shell was estimated to be in the order of 1·10−10 m2·s−1. The contribution of the Zn-gas evaporation/condensation microprocesses, which could occur in relation to the above diffusion through a nanostructured surface layer, was evaluated with numerical calculations in the temperature range of 550–950 K and for an average particle size of ZnO up to 100 nm. Our results suggest that the outward diffusion of metallic zinc takes place from the core of powder microparticles across the nano-grain boundaries of their modified surface layer, and can be further intensified by the presence of other inter-phase defects, such as nano-porosity.
The effect of capillary titanium spreading was found on carbon grains during the synthesis of tit... more The effect of capillary titanium spreading was found on carbon grains during the synthesis of titanium carbide. The combustion rate of the Ti-C-Ni and Ti-C-Ni-Mo systems, including the low-melting inert component, was studied versus the parameters of the ultrasonic field. Adding a copper melt to the initial mixture with the limiting wetting angle θ > 90° enhanced the effect of the ultrasonic field on the combustion rate. The phenomena of acoustic emission during SHS were also studied. The spatial acoustic emission area was shown to be localized near the combustion wave.
Wear, 1993
Abstract The effect of a carburizing regime and subsequent heat treatment on the wear resistance ... more Abstract The effect of a carburizing regime and subsequent heat treatment on the wear resistance of high chromium steels is estimated. Carburization raises the abrasive wear resistance and allows significant suppression of the adhesion phenomena under dry sliding. The results obtained allow us to determine the regime of surface hardening of high chromium steels required to produce the desired combination of wear resistance and bulk strength properties.
Doklady Physical Chemistry
International Journal of Self-Propagating High-Temperature Synthesis
A case of combustion in a heterogeneous random medium is considered when the characteristic scale... more A case of combustion in a heterogeneous random medium is considered when the characteristic scales of combustion wave are less than the sizes of structural elements of the reacting system. In this case, a rigid percolation combustion regime is possible, in which the process has a form of successive ignition and burning of connected reactive particles constituting a cluster spanning the opposite boundaries of the system. Gasless 2D systems were modeled. Prototypes for such a model are mechanically activated powder mixtures for the synthesis of intermetallic compounds (e.g., Ni-Al, Fe-Al, Ni-Ti, etc.) diluted with an inert component. Estimations and numerical modeling have shown that percolation regimes are possible if the following conditions are satisfied: (i) each particle can burn independently, I.e., the ratio of the combustion zone scale to the particle size is less than unity and the heat exchange between particles is hampered; (ii) the heat losses are close to the extinction l...
We have performed thermodynamic modeling of the reduction of iron scale (production waste of meta... more We have performed thermodynamic modeling of the reduction of iron scale (production waste of metallurgy and machine-building) by products of incomplete conversion of methane in oxygen for developing a process of obtaining iron powder with the use of a plasma jet. We have calculated the equilibrium composition of the gas phase and condensed interaction products at various temperatures and initial compositions of the reducing medium. The optimal process parameters providing reduction of scale to pure iron, i.e., the temperature range, the methane/oxygen ratio in the gaseous medium, and the scale/gas mixture mass ratio, have been determined.
Materials Science Forum, 1994
Journal of Engineering Physics, 1988
Journal of Engineering Physics, 1988
A macrokinetic description is presented for diffusion produced by a solidphase reaction in a bina... more A macrokinetic description is presented for diffusion produced by a solidphase reaction in a binary system. The kinetics of processes on the interphase boundary and diffusion with the phase volumes are considered. The effect of kinetic factors on the growth of intermetallic compounds is studied numerically.
Journal of Engineering Physics, 1990
Soviet Powder Metallurgy and Metal Ceramics, 1991
The use of boron carbide for producing wear-resisting powder composites based on iron requires ex... more The use of boron carbide for producing wear-resisting powder composites based on iron requires examination of the processes of structure formation during sintering of these materials. It has been shown that gas-transport processes in the Fe-C-B system at T _< 1000~ lead to breakdown of B4C particles and formation of a layer of iron boricles on the internal
Physical Review B, 1991
The analysis of experimental data on compound formation during annealing of thin-film and bulk di... more The analysis of experimental data on compound formation during annealing of thin-film and bulk diffusion couples reveals the influence of interface reactions on phase-layer growth kinetics. Based on the mechanism of phase changes during interdiffusion, allowing for the diffusion through the vacancies in the bulk as well as atom travel across the interface and lattice transformations, a model for a
Physical Review E, 1993
The relationship between the stochastic and deterministic approaches to the description of the dy... more The relationship between the stochastic and deterministic approaches to the description of the dynamic behavior for a nonlinear reacting system is studied. A self-propagating exothermal reaction in a heterogeneous medium has been chosen as an example. A stochastic model for this phenomenon is developed. The system is composed of cells characterized by temperature and degree of conversion, their transformation probability