M.Yu. Arseenko

Structure and properties of an Al2O3 powder coating formed by a cumulative detonation method

The strength of the Al2O3 powder coating formed by a cumulative detonation method on a steel St3 substrate is determined, and its structure is studied. The optimum conditions for deposition are chosen. They make it possible to form a dense high-strength coating with good adhesion to the substrate.

Properties, Peculiarities and Applications of Powder Coatings Formed by Multi-Chamber Detonation Sprayer

The paper describes the properties of Ti, Nickel-based, and Al2O3 powder coatings obtained through a new method of powder acceleration which allows to achieve the powder velocity of 1400m/s. The Ti-based coatings thus formed have nanocrystal and amorphous structure with nanodispersed ceramic compounds inclusions, and show the hardness of up to 16GPa, high plasticity and adhesion strength. The Nickel-based alloy coatings display both nanocrystal and amorphous structure. In ceramic Al2O3 coatings high spraying velocity allows filling in the space between the deformed oxide particles (about 0.053 microns in size) by nanocrystal and amorphous phases; thus, the coatings acquire a high degree of plasticity retaining high hardness of 1320 HV0.3 with the porosity below 0.5%. The Al2O3 coatings were tested and found effective for covering the surface of porous metal matrixes in burners.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ALUMINA POWDER COATINGS BY A NEW MULTI-CHAMBER DETONATION SPRAYER

The dense ceramic coatings based on alumina with hardness of 1100±25 HV0.3 and porosity of less than 1% have been prepared by multi-chamber detonation sprayer (MCDS) with a barrel length of 500mm. The intermetallic compound of type FeAl was revealed in the area of the coating that adjoins the substrate.

Properties and Peculiarities of WCCoCr Coatings Formed by Multi-Chamber Detonation Sprayer

Multi-chamber detonation sprayer (MCDS) was applied for deposition of WC-Co-Cr powder coatings on corrosion-resistant steel. Powder AMPERIT®554.074 WC-Co-Cr was used to deposit of a coatings. The coatings microstructures and phase compositions were characterized using SEM, OM and XRD techniques. Measurement of the microhardness of samples was done with a micro-hardness tester DM – 8B using a Vickers’s indenter with load on of 0.3 N. It was established that MCDS has provided the conditions for formation of a dense layer with porosity of less than 1.5 % and microhardness 750±50 HV0.3.

Effect of the surface modification of titanium nickelide by nitrogen and titanium ions on the adhesion to a nanosized carbon coating deposited by a pulsed vacuum-arc method

The adhesion strength of nanosized carbon coatings deposited by a pulsed vacuum-arc method to the titanium nickelide substrate preliminarily modified by the irradiation of nitrogen and titanium ions is studied. Preliminary modification of the titanium nickelide surface is found to prevent the swelling and exfoliation of a carbon coating.

Microstructure and Microhardness of Alumina-3wt. % Titania Coating Formed by a New Multi-Chamber Gas-Dynamic Accelerator

Alumina-titania coatings are widely used in industry for wear, abrasion or corrosion protection components. This paper presents the results of the investigation of the structure and microhardness of the alumina-titania (Al2O3:Ti wt ratio = 97:3) coating was prepared by a new multi-chamber gas-dynamic accelerator on corrosion-resistant steel substrate. Morphology of the powder particles, microstructure and phase composition of the coating were characterized with the use of scanning electron microscopy, X-ray phase analysis and Vickers hardness tester at a test load 0.2 kg. The results show that the microstructure of the alumina–3wt.% titania coating consists of region with different degrees of melting: the lamella built up from the fully melted particles of the powder, and partially melted regions. The developed coating by this method is highly dense (porosity of less than 0.2%) and tightly adherent.

Deposition and Characterization of CoCrAlY Coatings by Multi-Chamber Detonation Sprayer

In this study, a multi-chamber detonation sprayer (MCDS) was applied for deposition of Co-Cr-Al-Y powder coatings (200-250 mm thick) on nickel base superalloy JS6U (Russia). Powder Co-25Cr-11Al-1Y (d(0.1): 6.6 μm, d(0.5): 62.7 μm, d(0.9): 123,4 μm) was used to deposit of a coatings. The coatings microstructures and phase compositions were characterized using SEM, OM and XRD techniques. Measurement of the microhardness of samples was done with a micro-hardness tester DM – 8B using a Vickers’s indenter with load on of 0.1 N. It was established that MCDS has provided the conditions for formation of a dense layer with porosity 0.05% and microhardness 600±50 HV0.1.

Properties of Powder Coatings Formed by Gas-Dynamic Accelerator

Abstract The paper presents the results of investigating the properties of metal and ceramic coatings deposited on the steel or the aluminium substrates by using a multi-chamber gas-dynamic accelerator. The multi-chamber gas-dynamic accelerator (MCDS) has replaceable nozzles and operates with a fuel mixture of low-pressure gases – propane (30 %) + butane (70 %) – oxygen – air. The velocity of the frontal area of the cloud of the Al 2 O 3 powder with particle sizes of 5.6 – 22.5 μm at a nozzle length of 500 mm is 1300 ± 200 m/s. MCDS with a nozzle length of 500 mm provides the conditions for formation of a dense ceramic layer having hardness of 1320 ± 25 HV 0.3 and porosity of less than 1 %. Productivity of the technology is 0.72 kg/h at a deposition efficiency - 65 %, flow rate of oxygen equal to 7.7 m 3 /h, and flow rate of propane + butane equal to 1.3 m 3 /h. High adhesion of the ceramic layer to the substrate is provided by the transition layer up to 15 μm thick. MCDS allows form Nano-crystalline coating of the titanium or nickel based alloy powders. The dense layer of lamellas and deformed particles of powder is formed on the sample surface. Lamellas consist of Nano-crystalline grains size of 30 – 100 nm. Scratch-test has shown that the coatings are plastic and have high adhesive and cohesive strength.

Tribological characteristics of nanosized carbon coatings obtained by the pulsed vacuum-arc method on the modified TiNi surface

Tribological tests of nanosized carbon coatings produced by the pulsed vacuum-arc method on the surface of NiTi premodified by ions of nitrogen and titanium are conducted. The surface modification and formation of a carbon coating 180 nm thick on the surface of a softer material, titanium nickelide, is shown to considerably increase wear resistance and reduce the coefficient of friction.