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Том 41, № 1 (2019)
- Год: 2019
- Статей: 9
- URL: https://journals.rcsi.science/1063-4576/issue/view/11669
Production, Structure, Properties
Tungsten Heavy Alloys with Molybdenum, Y2O3 and Lanthanum. A Review
Аннотация
The consolidated results of studies of tungsten doping with various metals and compounds (Ni, Fe, Cu, Mo, Y2O3, La2O3) are presented, the advantages of doping with regard to its conditions, microwave and plasma sintering techniques are shown. It has been found that the mechanical properties of tungsten are significantly improved by the addition of the above elements. The resulting heavy fame tungsten can be used to protect against nuclear radiation.
1-16
Luminescent and Radiation Characteristics of Monocrystalline Diamond Powders
Аннотация
Different types of luminescence (photoluminescence, cathodoluminescence, X-ray luminescence in the range from 360 to 900 nm of monocrystalline diamond powders with grains from 125/100 to 250/200 µm) were studied. The powders were divided into different groups according to the perfection degree of their crystal structure and magnetic susceptibility value. At the room temperature the H3 luminescence of a diamond defect prevailed in all groups of crystals. At the liquid nitrogen temperature in the spectra of cathodoluminescence nickel centers dominated. Using selected diamonds and Sylgard 184 polysiloxane elastomer the samples of composite scintillators were made and their radiation resistance investigated. The higher radiation resistance relative of the standard YSO:Ce scintillators to the irradiation with fast electrons was installed.
17-23
Low Temperature Thermal Conductivity of Heavily Boron-Doped Synthetic Diamond: Influence of Boron-Related Structure Defects
Аннотация
Thermal conductivity of single-crystal boron-doped diamonds (BDD) with ∼2 × 1019 cm−3 (∼120 ppm) and 5 × 1019 cm−3 (∼300 ppm) boron content was studied by a steady-state method in a temperature range of 20–400 K. The obtained data were analyzed within Callaway model framework. The values of dislocation density obtained from best fit of experimental data and from density of etch pits measuring were compared. Their discrepancy suggests presence of some other boron-related defects in crystal lattice.
24-31
Plasma-Enhanced CVD Equipment for Deposition of Nanocomposite Nanolayered Films
Аннотация
The paper describes the main design principles of plasma-enhanced chemical vapor deposition (PECVD) equipment based on a Mod. VUP-5(M) universal vacuum pumping station, and the application of such equipment for deposition of thin films, including nanolayered ones, from vapors of usually liquid precursors. The method can be classified as PECVD in a gas atmosphere activated by E-type radio-frequency (RF) plasma in continuous flow systems (the open-tube method). The equipment is universal in terms of the types of precursors to be used and has a sufficient set of process variable in order to provide deposition of a wide range of coatings with a controlled thickness from 1 to 2000 nm. The PECVD equipment favorably supplements the VUP-5(M) functionalities and extends performance without any significant alteration of its design.
32-37
Formation and Physicochemical Properties of High Entropy Oxide Based on Equiatomic Alloy CrFeCoNiMn
Аннотация
The physicomechanical and X-ray investigations of high entropy oxide coating obtained by the cathode sputtering of multicomponent alloy CrFeCoNiMn in plasma of compressed vacuum-arc gaseous discharge have been conducted. The hardness of high entropy oxide coating is shown to reach the level of 27 GPa at the elasticity modulus of 270 GPa, which decreases to 17 GPa after annealing at temperature 1100°C during 300 min in the open air. The friction coefficient of coating at small sliding velocities amounts to 0.045–0.132 depending on the coating hardness.
38-42
The Development of the Electrochemical Deposition Process of Nickel-Diamond Coating with Phosphorus Modified DND
Аннотация
Adding phosphorus-modified detonation nanodiamonds to a standard electrolyte solution for electrochemical nickel plating raises the coating microhardness up to 660 kg/mm2, wear resistance by a factor of 8, and corrosion resistance up to 70-fold.
43-48
Influence of Obtaining Conditions on Microstructure, Phase Composition and Properties of Eutectic Alloy of WC-W2C System
Аннотация
The influence of the obtaining conditions on microstructure, phase composition and properties of eutectic alloy of the WC-W2C system (relit), which is widely used as a surfacing material to strengthen the wearing parts, was installed. Using scanning electron microscopy, X-ray diffraction and durometric analyzes, it was found that the increase in mechanical properties is satisfactorily correlated with a decrease in the ratio between the number of phases of W2C, WC and WC1−x, the thickness of the phase layers in the grains, and the elongation of the latter.
49-52
Criterion-Based Assessment of Performance Improvement for Aircraft Structural Parts with Thermal Spray Coatings
Аннотация
The paper presents a block diagram that shows the benefits of protective-coating thermal spraying methods and the main factors that have an effect on the coating structure and properties. The authors put forward a procedure for preliminary prioritizing (in terms of effectiveness) of concrete coatings and the corresponding thermal spraying method. The influence of machining on the performance of coated parts is taken into account. The criterion-based assessment of performance improvement for aircraft structural parts with thermal spray coatings is proposed to be implemented within the framework of a conceptual approach that involves the use of an integral effectiveness criterion including single, group, and complex components.
53-59
Tools, Powders, Pastes
Optimization of Designing on Cutter Parameters of PCD Saw Blades by Simulation Analysis
Аннотация
The cutter parameters of PCD circular saw blades play a decisive role in the wood cutting process, they directly affect the machining surface quality and tool life. Simulation analysis of the cutting stress and deformation of PCD wood circular saw blades with different cutter parameters is carried out using the finite element method. The results show that the maximum shear stress of the PCD saw blade in cutting process are all in a safety range with safety coefficient of about 3.5–4.0, and the maximum displacement of PCD saw blades are about 4.8–4.9 µm in the axial direction and about 10 µm in radial and rotation directions. It was found that the best cutter parameters of the PCD circular saw blades are rake angle γ = 15° and rear angle α = 15°, in which the relative low stress of 58.9 MPa and relative smaller displacement of can be achieved.
60-68