When applying a vacuum-arc discharge plasma coating to profilecomposite items, such as twin turbine blades, unicycle blades, etc., a problem might occur with ensuring the tolerance on the coating ...thickness. This article presents the obtained dependence of the nonuniformity of the coating thickness on the geometric parameters of the inter-blade channel—its length and width. We develop a simulation model for calculating the distribution of the thickness of the vacuum-arc discharge plasma coating for the profilecomposite parts having shadow zones.
We study the influence of different grain size (density of grain boundaries) on the way of phase transformations in the surface layers of 316 L-type austenitic stainless steel under ion-plasma ...treatment. Using thermomechanical treatments, we fabricated a series of specimens possessing a single-phase austenitic structure, close density of the defects of the crystal lattice and different grain sizes (fine-grained with d ≈ 3–6 μm and coarse-grained with d ≈ 55 μm). These specimens were subjected to ion-plasma surface treatment at 550 ± 10 °C in N2+C2H2+Ar gases mixture to provoke a precipitation hardening. Although fine-grained and coarse-grained specimens possess similar penetration depth of interstitial atoms (N, C) under ion-plasma treatment (≈40–48 μm), the distribution of interstitials and phase composition are different in them. After ion-plasma treatment, specimens with low density of grain boundaries (coarse-grained structure) maintain a high level of N, C atoms in the solid solution of austenite (a = 0.3653–0.3674 nm) with a strip-like arrangement of Fe4(N,C) particles within grains, while precipitation of Cr(N,C) phase is suppressed. For these specimens, tensile diagrams have the extended linear stages typical of nitrogen-bearing austenitic steels, and the loss of ductility assisted with ion-plasma treatment is the smallest among studied specimens. Ion-plasma treated specimens with high density of grain boundaries (fine-grained structure) are prone to a decomposition of Fe-γN,C phase with the formation of grain-boundary and intragranular Cr(N,C) and Fe-α phases and partial preservation of a solid-solution strengthening of austenite (a = 0.3597–0.3622 nm). Precipitation hardening is more characteristic of these specimens and their flow curves are parabolic. The complex fracture mode of the specimens subjected to ion-plasma treatment is caused by the surface solid-solution strengthening and precipitation hardening. In the surface-hardened region (where the concentrations of N, C atoms are the highest), brittle quasi-cleavage fracture occurs due to the presence of Fe-based and Cr-based precipitates and austenite oversaturated with interstitials.
•316 L steel with different grain size was modified with ion plasma treatment (IPT).•Phase composition of IPT-processed steel is grain size-dependent characteristic.•IPT-assisted Fe-γN,C and intragranular Fe4(N,C) prevail in coarse-grained specimens.•Fe-γN,C + Cr(N,C)+Fe-α microstructure is peculiar for fine-grained steel after IPT.
Vacuum Arc Deposition of Y-Al-O Coating Nazarov, A. Yu; Maslov, A. A.; Ramazanov, K. N.
Russian physics journal,
2024/1, Letnik:
66, Številka:
11
Journal Article
Recenzirano
The X-ray diffraction analysis of in situ phase transformations in the Y–Al–O coating is conducted by using the synchrotron radiation beam. The paper also presents results of the coating deposition ...on a conventional system for comparison. It is shown that in depositing coatings on static samples during in situ synchrotron radiation, the formation of Y
2
O
3
and YAlO
3
phases and Y
2
Al and Y
3
Al
2
intermetallic compounds occurs in the coating structure. When the coating is deposited onto rotating substrates without synchrotron radiation, the formation of Y
4
Al
2
O
9
, yttrium and aluminum is observed.
Cathodic arc deposition of coatings onto the surface of products with a complex geometry (coupled turbine blades, integrally bladed disks) can be complicated by the problem of the coating thickness ...tolerance. This paper suggests experimental dependences between nonuniformity of the coating thickness synthesized by cathodic arc deposition and geometrical parameters of the blade channel, namely its length, width, and curvature radius.
A method of surface hardening of titanium alloy VT6 in glow discharge nitriding with hollow cathode effect (HCE) is considered. The influence of the HCE on the glow discharge parameters, structure ...and phase composition of alloy VT6 is determined. The current-voltage diagrams are obtained, the microhardness of the treated surface is evaluated, the phase composition of the specimens nitrided in glow discharge with and without HCE is analyzed.
In this paper, the ionization and recombination coefficients of dense semiclassical hydrogen plasma on the basis of the effective interaction potential have been investigated. For this goal the Bohr ...- Lindhard method and method phase function have been applied to obtain the electron capture and ionization cross sections. The electron capture cross section has been calculated in the framework of the perturbation theory. The effective interaction potential, which takes into account the screening effects at large distances and quantum diffraction effects at short distances, was used. The results of the investigation show the behaviour of the calculated kinetic coefficients with a change in the plasma parameters: the ionization coefficient decreases with increasing density and (or) coupling parameter while the recombination coefficient increases.
On plasma neutralization of the ion beam Shalenov, E O; Dzhumagulova, K N; Ramazanov, T S ...
Journal of physics. Conference series,
12/2020, Letnik:
1697, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Simulation of the thermal motion of ions in a spherical bunch was performed on the basis of the molecular dynamics. The Yukawa potential was used to describe the ion interactions. Obtained data ...showed good agreement with results of theoretical investigation. The conclusion was done that INURA accelerator needs good plasma neutralization in order to keep transverse size of the ion beam.
The quality characteristics of Ti-TiN multilayer vacuum ion-plasma coatings are studied, among which are as follows: roughness and adhesive strength. It is shown that additional ion bombardment ...contributes to obtaining high-quality coatings. Ion bombardment has a significant impact on the state of metal surface layer. In the process of ion bombardment, the conditions for formation of active adsorption centers as well as formation of a fine-grained structure, nanoscale grains and layers are created.
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