Research and development of processes of vacuum ion-plasma parts surface treatment

The application of electron-ion-plasma technologies for increasing the service life of machine parts, tools and technological equipment has been investigated. The technology of vacuum ion-plasma surface treatment is proposed for the deposition of coatings, which makes it possible to create internal, external and combined coatings. The manufacturability of coating methods is largely determined by the level of the developed equipment. The entire technological process of deposition of wear-resistant coatings on parts of friction units is carried out in one cycle on a BRV600F vacuum unit, which is equipped with all the necessary technical means. A method has been developed for the technology of obtaining a superhard carbon-metal coating with desired properties, namely, improving the quality of diamond-like films by changing their structure and composition, while the lower layer should have high adhesion to the substrate material, the middle layer should have high hardness and increased wear resistance, and the upper layer should have good thermal conductivity and heat resistance with low coefficient of friction.

Increasing the life of the center plate-center bowl friction unit of a freight car by applying a combined coating formed by electrospark alloying

An increase in the operational reliability of friction units of railway transport by applying antifriction combined coatings formed by electrospark alloying, which ensures their greater strength and adhesion to metal, is considered. Keywords: electrospark alloying combined antifriction coating, strength, adhesion. [email protected]

MACHINE SHAFTS RECOVERY BY COMBINING ELECTROMECHANICAL PROCESSING WITH THE USE OF POLYMER MATERIALS

Currently, one of the most acute problems of repair production is the lack of highly efficient, but at the same time easy-to-implement technological processes for restoring the landing surfaces of shafts and axles of machine mechanisms. The solution to this problem is in the combination of simple and inexpensive technological processes with the production of multilayer coatings with specified guaranteed physical, mechanical, rheological and tribotechnical properties, as well as in ensuring the necessary dimensional and geometric accuracy of the restored joints of parts. (Research purpose) The research purpose is in developing a typical technological process for restoring the landing surfaces of the shafts of machine mechanisms for rolling bearings by combining electromechanical processing with the application of polymer coatings. (Materials and мethods) The article presents the studies of the physical, mechanical and rheological properties of polymer materials and combined coatings on the AI-7000M breaking machine of GOTECH Testing Machines Inc. The UGN60R software package was used to process the obtained results. (Results and discussion) The article presents a mathematical model that allows us to describe the process of loading the combined coating of a worn part with the determination of its stress-strain state at the installation stage and during operation of the restored fixed joint. As a result, the load affects the change in contact pressures to a greater extent, and the volume modulus and the shear modulus of the polymer to a lesser extent. (Conclusions) A new standard technological process has been developed and tested for restoring worn-out landing surfaces of shafts for rolling bearings of transmission units of domestic and foreign tractors, cars, agricultural machinery, equipment of processing industries by combining electromechanical processing with a coating based on polymer compositions ANATERM-201 and Loctite 3472.

LARGE CANALS RECONSTRUCTION AND THEIR EFFICIENCY ASSESSMENT

Purpose: to define the efficiency of large irrigation canals on the example of the Donskoy main canal and the Bolshoy Stavropol canal during their reconstruction. Materials and methods. The use of geocomposite materials is of interest to creating combined linings of large canals. A geocomposite anti-seepage structure made without a protective layer at the bottom and part of the slope and a concrete-film element in the zone of wave and ice impact is considered. The application of such a combined lining makes it possible to reduce the cost of the anti-seepage screen, to shorten the construction time, to reduce the canal roughness and to increase its water-carrying capacity. The method of hydraulic research is based on the field data of the Bolshoy Stavropol and the Donskoy main canals for average and maximum values of hydraulic parameters. In particular, it was necessary to determine the roughness coefficients of the canal in the area between the sections. Results. A feature of the reconstruction of the most dangerous sections of the Donskoy main canal is the close location of the groundwater level to the surface, which leads to the transition of free filtration to a banked-up one. According to the results of calculations, the total losses are 13.7×10³ cubic meters/day in the section 57–70 km, and with canal lining – 0.504 cubic meters/day, which is 2.09 times less than with banked-up filtration in the earthen bed. Conclusions. The most effective types of linings with the use of geocomposites which, as shown by field surveys, are reliable combined coatings, are presented. Anti-seepage facilities made of concrete and reinforced concrete have high impermeability, though at the same time they are destroyed over time under the influence of water and freezing-thawing processes.

Study of voltages in inhomogeneous models of supplied combined coatings by the polarization-optica method for monitoring their state

The polarization-optical method for studying stresses in heterogeneous models of combined deposited coatings is considered. The physical foundations of the method and its essence are described. Investigations of the tense state of coatings on heterogeneous models made of viscoelastic materials are presented. Creep curves were obtained, on the basis of which the dependence of specific deformation δ(t) was built, from which the values of the isochron module E2(t) and the price of the strip σ0.2 (t) as a function of time for viscoelastic material were determined.

A Novel C1-Esterase Inhibitor Oxygenator Coating Prevents FXII Activation in Human Blood

The limited hemocompatibility of currently used oxygenator membranes prevents long-term use of artificial lungs in patients with lung failure. To improve hemocompatibility, we developed a novel covalent C1-esterase inhibitor (C1-INH) coating. Besides complement inhibition, C1-INH also prevents FXII activation, a very early event of contact phase activation at the crossroads of coagulation and inflammation. Covalently coated heparin, as the current anticoagulation gold standard, served as control. Additionally, a combination of both coatings (C1-INH/heparin) was established. The coatings were tested for their hemocompatibility by dynamic incubation with freshly drawn human whole blood. The analysis of various blood and plasma parameters revealed that C1-INH-containing coatings were able to markedly reduce FXIIa activity compared to heparin coating. Combined C1-INH/heparin coatings yielded similarly low levels of thrombin-antithrombin III complex formation as heparin coating. In particular, adhesion of monocytes and platelets as well as the diminished formation of fibrin networks were observed for combined coatings. We could show for the first time that a covalent coating with complement inhibitor C1-INH was able to ameliorate hemocompatibility. Thus, the early inhibition of the coagulation cascade is likely to have far-reaching consequences for the other cross-reacting plasma protein pathways.

Individual and Combined Coatings of Chitosan and Carnauba Wax with Oregano Essential Oil to Avoid Water Loss and Microbial Decay of Fresh Cucumber

The objective of the present study is to evaluate the effect of individual and combined coatings of chitosan (0.008 g·mL−1) and carnauba wax (0.1 g·mL−1) with oregano essential oil (OEO, 0.08 g·mL−1) to reduce dehydration and microbial decay of fresh cucumbers stored at 10 °C. Chitosan-OEO-wax films showed the lowest water vapor transmission rate (0.141 g·m−2·h−1), compared to single chitosan films (0.257 g·m−2·h−1). While chitosan-OEO films completely inhibited the in vitro growth of Alternaria alternata and reduced the growth of Salmonella Typhimurium, Escherichia coli O157:H7, mesophilic bacteria, and fungi isolated from decayed cucumbers. Besides, the infrared analysis of chitosan-OEO-wax films showed shifts in O–H and N–H absorption bands, indicating possible hydrogen bonding between the components. Wax and wax-OEO were the most effective coatings to prevent weight loss in cucumbers during 15 days of storage at 10 °C, while the most effective antimicrobial treatments were chitosan and chitosan-OEO. Therefore, these results showed that carnauba wax and carnauba wax-OEO coatings were the most effective in weight loss, whereas chitosan and chitosan-OEO were the most effective to reduce the microbial load of the treated fresh cucumber.