CHARACTERIZATION AND ELECTROCHEMICAL CORROSION ANALYSIS OF HEAT-TREATED REINFORCED HA COATINGS DEPOSITED BY VACUUM PLASMA SPRAY TECHNIQUE

Herein, a biomimetic coating of hydroxyapatite (HA)–Al2O3 and HA–ZrO2 was deposited on Ti–6Al–4V-alloy using vacuum plasma spray (VPS) technique. The bond-coat of ZrO2 has been introduced between the substrate and reinforced HA coatings to study the effect of bond-coat on structural, mechanical properties and electrochemical corrosion performance of the developed coatings. In addition, the impact of thermal treatment of coating was investigated on these properties too. Coating characteristics, such as morphology, porosity, surface roughness, and crystallinity were investigated. The corrosion performance of coatings was tested in Hank’s-based salt solution (HBSS). Significant enhancement in crystallinity and surface-hardness has been witnessed after heat treatment; nevertheless, porosity reduced. The electrochemical corrosion study revealed that the corrosion resistance of heat-treated samples was better than the as-sprayed coatings samples. The intensity of XRD peaks of all coatings increased after 24[Formula: see text]h immersion in HBSS for the electrochemical test in comparison to the intensity of peaks before the corrosion test.

Application of Avinit vacuum plasma technologies Avinit to the manufacture of high-precision full-size gears

Avinit duplex technologies have been developed, combining Avinit N plasma nitriding of finished high-precision parts with subsequent application of Avinit superhard antifriction coatings in a single technological process Due to the absence of a brittle layer on the nitrided surface after precision nitriding, the preservation of the original geometric dimensions that do not require further mechanical refinement, and the compatibility of the processes of plasma precision nitriding of Avinit N and the vacuum plasma deposition of functional coatings Avinit C, duplex technologies allow the deposition of strong adhered, high-quality coatings. The effect of the duplex process on the dimensions of parts during plasma nitriding of high-precision gears and the application of Avinit C functional coatings was investigated, the properties of the nitrided layer and the parameters of Avinit coatings were studied. Plasma precision technology Avinit N allows nitriding of finished parts without changing dimensions, including gears of 4 degrees of accuracy. Avinit N nitriding time is 2 ... 4 times less than with gas nitriding. The coating of Avinit C310 parts increases the microhardness of the surfaces of the parts and reduces the coefficient of friction, while it has sufficient adhesion to the working surfaces of the gear teeth and bearing raceways. Manufacturing of high-precision gears with accuracy grade 4 using Avinit duplex technologies was carried out. Analysis of the results shows that, within the measurement accuracy, no changes in the profiles of the teeth, their location on the ring gear, as well as the location of the gear ring relative to the measuring bases are observed. Plasma nitriding makes it possible to reduce the nitriding time by more than two times compared to gas nitriding, while the thickness of the layer of the brittle phase with the maximum surface hardness is ensured within the specified values ​​to ensure the necessary indicators of contact and bending long-term strength in the manufacture of gears according to the degree of accuracy 4 without grinding after nitriding. Measurements of the ring gear after nitriding and coating showed that there were no changes in the geometry of the gear processed by duplex technology. Avinit C310 anti-friction coating 1.5 microns thick does not distort the geometry of the tooth profiles. All parameters of the ring gear manufactured using the Avinit duplex technology correspond to accuracy grade 4 in accordance with the requirements of technical documentation. The gears manufactured using the Avinit duplex technology were tested as part of the AI-450M engine reducer at the Ivchenko-Progress hydraulic brake stand according to the program of equivalent cyclic tests. A pair of experimental gears were installed in the engine reducer instead of the serial wheels of the second stage of the reducer. The total test time of the wheels was 26 hours. After testing, no damage to the gear, including the Avinit coating, was found. Antifriction coating Avinit C310 with a thickness of 1.5 microns does not distort the geometry of the tooth profiles during testing as part of the AI-450M engine reducer. Measurement of the parameters of the teeth showed a complete absence of wear.

Колибри, тукан и цапля. С каким оборудованием компания Gambetti Kenologia выходит на российский рынок?

Разработка оборудования для вакуумных, плазменных и тонкопленочных технологий – важная техническая задача современной наноиндустрии и микроэлектроники. Современные научные исследования немыслимы без высококачественной плазменной очистки поверхностей кремния, тонких полупроводниковых пленок и полимеров. Компания Gambetti Kenologia уже более 46 лет активно разрабатывает и продает качественное оборудование, использующееся в биомедицине, микрофлюидике и очистке металлов. Ориентированность на клиента, обеспечение сервисного обслуживания по всему миру делает ее весьма привлекательной и для российского рынка, на котором его будет представлять отечественная компания ООО "МИВАТЭК". Development of the instrumentation for vacuum, plasma and thin film technology is an important technological task for contemporary nanoindustry and microelectronics. Modern scientific research is inconceivable without high quality plasma cleaning of the surfaces of silicone, semiconductor thin film and polymers. For more than 46 years the company Gambetti Kenologia has been actively developing and selling high standard equipment which is being used in biomedicine and microfluidics, cleaning of metals. The client focus, provision of service support around the world makes the company rather attractive for the Russian market also, and there it will be represented by the national company MIVATEK LLC.

Radiative Surface Waves in Layered Plasma–Dielectric Structures and Prospects of Their Application in Plasma Microwave Electronics

Surface waves in layered systems consisting of material media with different frequency dispersions are considered: dielectric–plasma–vacuum, vacuum–plasma–plasma, and dielectric–vacuum–plasma. It is shown that in such systems, one of the surface waves can be radiative into a medium that does not form an interface for the surface wave under consideration, in view of which the wave becomes decaying. In the dielectric–vacuum–plasma system, there is only one surface wave localized at the vacuum–plasma interface, which is radiative into the dielectric in a certain region of wavenumbers with a not too small thickness of the vacuum layer. For all cases, the possibilities of exciting surface waves of a layered structure by an electron beam are analyzed. It is indicated which surface waves will be excited most efficiently. The prospects of using such waves in plasma microwave electronics in the development of sub-terahertz and possibly terahertz frequency ranges are shown.

VACUUM-PLASMA PROPERTIES OF STAINLESS STEEL AFTER IMPACT OF COMBINED GLOW-MICROWAVE DISCHARGES IN ARGON ATMOSPHERE

The experiments were carried out to determine the vacuum-plasma characteristics (mainly erosion and outgassing rate in a vacuum) of the stainless steel 12X18H10T before and after processing the walls of the vacuum chamber with the glow discharge and combined, glow-microwave plasma discharges in argon atmosphere. The current-voltage characteristics, the electron density and electron temperature were measured. It was observed that the discharge voltage in the combined regime is significantly lower than in glow discharges. In some modes, this voltage decrease can be up to 200 V. It was shown that erosion of stainless steel 12X18H10T in the combined discharges is 70 %, less than in the glow discharges. Measurements were made of the outgassing rate of 12X18H10T stainless steel with the thermal desorption probe in situ in the DSM-1 vacuum chamber. It was shown that cleaning the chamber wall by the glow discharge during 5 h leads to a decrease in the outgassing rate from 5.5·10-5 to 1·10-5 (Torr.l)/(s.cm2) . When the chamber wall is treated with GM discharge starting from nearly the same initial conditions the outgassing rate decreased to 3·10-6 (Torr.l)/(s.cm2). Spectral measurements of the plasma radiation of a glow and combined discharges show a decrease in the ratio of the peaks of argon ions and neutrals during the transition from a glow discharge to a combined one.