Begell House Inc.
High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
HTM
1093-3611
23
2
2019
FORMATION OF HARD AND WEAR-RESISTANT NIOBIUM CARBIDE COATINGS ON HARD-ALLOY TOOLS BY A VACUUM–ARC METHOD
97-105
10.1615/HighTempMatProc.2019030185
Andrej K.
Kuleshov
Belarusian State University, 4 Nezavisimosty Ave., Minsk 220030, Belarus; LLC Scientific and Technical Center Vist Group Sensor, 2B Novatorskaya Str., Off. 204, Minsk, 220053, Belarus
Vladimir V.
Uglov
Belarusian State University, Minsk, 220030, Belarus; National Research Tomsk State University, Tomsk, 634050, Russia
V. M.
Anishchik
Belarussian State University, 4 Nezavisimost Ave., Minsk, 220030, Belarus
V. A.
Firago
Belarussian State University, 4 Nezavisimost Ave., Minsk, 220030, Belarus
D. P.
Rusalski
Belarusian State University, 4 Nezavisimost Ave., Minsk, 220030, Belarus
Alexander A.
Malashevich
Belarusian State University, 4 Nezavisimost Ave., Minsk, 220030, Belarus
I. A.
Sakovich
Belarussian State University, 4 Nezavisimost Ave., Minsk, 220030, Belarus
heating by Nb ion impact
niobium carbide coatings on hard alloy
element composition
hardness
adhesion
The temperature fields of a hard-alloy tool surface during niobium ion impact were determined by thermography. The temperature of the surface layers reaches a maximum value of
1100–1250°C after exposure of 40 s to Nb ion, and it does not change with increase in the exposure time to 1 min. Ion exposure for 1 min leads to the formation of a carbide layer (Nb, W)C0.7, in the surface layer with a thickness of about 0.4 μ;m. Subsequent plasma deposition of Nb in methane atmosphere forms an NbC coating. The hardness of the formed niobium-based and tungsten carbide-based layers reaches 35–65 GPa. Adhesive resistance to cracking and destruction of NbC coatings with a sublayer of (Nb, W)C0.7 increases at least 2 times compared to an NbC coating.
THE EFFECTS OF BORIDING AND HEATING ON THE DUCTILITY, STRENGTH, AND TOUGHNESS OF AISI 1045 STEEL
107-120
10.1615/HighTempMatProc.2019030266
Muthiah
Prince
Department of Mechanical Engineering, Sri Krishna College of Technology,
Coimbatore, Tamil Nadu, 641042, India
A. Justin
Thanu
Park College of Engineering and Technology, Coimbatore, Tamilnadu, India
steel
boriding
strength
toughness
ductility
grain size
In this investigation, the effects of boriding and heating on the ductility, strength, and toughness of AISI 1045 steels are studied experimentally by using a shear punch test. Boriding reduces the ductility, strength, and toughness of steel samples and the impact of boriding on steel samples is explained through the growth of acicular borides, case depth (particularly FeB), grain coarsening, and hardness gradient depending on the boriding time. The effects of boriding and heating are compared. The effects of boriding and heating on grain coarsening are explained by a
mechanism based on the huge difference between the thermal conductivity between the iron and iron borides. The results indicate that the boriding reduced the ductility by 5–25%, whereas the heating enhances the ductility by 5–12%. On the contrary, heating reduces the strength by 14–30% and the addition of boron compensates the loss significantly, and this further is enhanced by increasing the boriding time. Both boriding and heating enhanced the reduction in toughness by 38–45% and 12–23%, respectively.
THERMAL MODES IN FORMATION OF CARBON NANOMATERIAL UNDER CONDITIONS OF HIGH-VOLTAGE ATMOSPHERIC PRESSURE DISCHARGE
121-155
10.1615/HighTempMatProc.2019030532
Kirill O.
Borisevich
Advanced Research and Technologies LLC, 2a Tolbukhin Str., room 7, Minsk,
220012, Belarus
A. P.
Chernukho
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
Serguei A.
Zhdanok
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
carbon nanotubes
decomposition of hydrocarbons
high-voltage discharge of atmospheric pressure
carbon nanofibers
This paper contains the results of an experimental study and simulation of physical and chemical processes of decomposition of a methane mixture with air in a high-voltage discharge plasma of atmospheric pressure. The results of comparison of the two-dimensional model of the process with experimental points are given for varying discharge parameters and the relative methane content
in the working mixture. Under the conditions of a real experiment, the temperature profiles and concentration distributions of the reaction products in the discharge zone, as well as the evolution of the gas mixture composition in the course of conversion, were obtained by means of modeling. On the basis of the research carried out, conclusions were made about the influence of the thermal
modes of the process on the formation of carbon nanomaterial.
NUMERICAL STUDY OF GAS HEATING IN OZONE GENERATED BY DBD IN OXYGEN
157-164
10.1615/HighTempMatProc.2019030196
Amar
Benmoussa
Laboratoire de Physique des Plasmas, Matériaux Conducteurs et leurs Applications (LPPMCA), Université d'Oran des Sciences et de la Technologie USTO-MB, Faculté de Physique, Oran 31000, Algeria; Ecole Supérieure en Génie Electrique et Energétique (ESG2E), Oran, Algeria
Barkahoum
Larouci
Laboratoire de Physique des Plasmas, Matériaux Conducteurs et leurs Applications, Université d'Oran des Sciences et de la Technologie USTO-MB, Faculté de Physique, Oran 31000, Algeria; Université Médéa Yahia Farés, Faculté Physique, Médéa, Algeria
Ahmed
Belasri
Laboratoire de Physique des Plasmas, Matériaux Conducteurs et leurs Application (LPPMCA), Université des Sciences et de la Technologie d'Oran, USTO-MB, Algérie
ozone generation
gas temperature
DBD
modeling
The goal of the present work is to highlight the gas temperature effect in ozone generated by dielectric
barrier discharge (DBD) in pure oxygen (O2). In this study, a one-dimensional fluid model was used to describe the discharge behavior. The study of the gas heating phenomena study in the frame of this paper is due to the gas heating effect. The gas temperature profile obtained in the DBD in oxygen was calculated by means of the heat transport equation. The results show that the rise of the gas temperature in the DBD inoxygen is more important near the dielectrics. The high value of gas temperature in this region is limited by the increase in the electric field and ion current density.
HIGH-TEMPERATURE PYROLYSIS OF PROPANE AND METHANE − THE SHOCK TUBE INVESTIGATION
165-179
10.1615/HighTempMatProc.2019030409
Mikhail V.
Doroshko
A.V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus
shock tube
propane pyrolysis
methane pyrolysis
soot formation
condensed carbon particles
optical diagnostics
soot yield
induction time of soot inception
Using laser light extinction and emission of intermediate radicals C2 and CH, the pyrolysis of propane and methane was investigated by a shock tube technique. The experiments were carried out with the initial mixtures of 4% C3H8 + 96% Ar and 4% CH4 + 96% Ar in the temperature ranges 2100-3400 K and 2600-3700 K behind the reflected shock wave, respectively. The kinetic characteristics of the pyrolysis process − temperature profiles of the soot particle yield and the induction time of soot inception were determined. It is shown that the maximum yield in propane is observed in the interval of 2500-2600 K. The increase in the soot yield with temperature is typical of methane throughout the entire range investigated. As follows from the experimental data obtained, the temperature dependence of the induction time corresponds to the Arrhenius-like law.
Samples of the materials deposited on high-temperature decomposition were analyzed by the electron diffraction method, as well as using a transmission electron microscope. It is shown that the finely dispersed carbon particles formed in the pyrolysis of the propane-argon mixture have a predominantly amorphous structure, whereas in the case of the methane-argon mixture the presence of individual crystalline inclusions is noted.
INFLUENCE OF EVAPORATION AND HYDRODYNAMICS EFFECTS ON SURFACE MODIFICATION OF METALS UNDER THE ACTION OF COMPRESSION PLASMA FLOWS
181-194
10.1615/HighTempMatProc.2019030485
Raman S.
Kudaktsin
A.V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus
Valiantsin M.
Astashynski
A.V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences
of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; National Research Nuclear University "MEPhI" (Moscow Engineering Physics Institute), 31 Kashirskoe Highway, Moscow, 115409, Russia
Anton M.
Kuzmitski
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15, P. Brovki Str, Minsk 220072, Belarus
compression plasma flow
materials modification
surface modification
nanostructures
Use of compression plasma flows opens wide possibilities for modification of metals and semiconductors by creating deep uniformly doped surface layers with elevated service characteristics. In the present work, evaporation and hydrodynamic effects in metals (iron, copper, aluminum) under the action of compression plasma flows are studied theoretically and experimentally. In experimental onditions,
plasma flows were generated by employing a magnetoplasma compressor of compact geometry with storage battery energy of 15 kJ. The lifetime of stable plasma flow was 100 µs. It was found that at a power density of 5−12 GW/m2 intense ablation of material from the metal surface occurs. Modeling of heat transfer processes on the basis of the Stefan problem with account for melting and evaporation showed that the observable ablation of material cannot be explained only by evaporation. It was found
experimentally that hydrodynamic removal of metal in a liquid state under high plasma flow pressure (10−30 atm) makes a substantial contribution to the total ablation. The proportion of hydrodynamic removal grows with increase of the plasma flow power density.