The article compares the properties of multilayer composite wear-resistant coatings of Zr–ZrN–(Zr, Mo, Al)N, Ti–TiN–(Ti, Mo, Al)N, and Cr–CrN–(Cr, Mo, Al)N. The investigation was focused on hardness, resistance to fracture during scratch tests, elemental composition, and structure of the coatings. Experiments were carried out to study the wear resistance of coated carbide tools during the turning of 1045 steel and of NiCr20TiAl heat-resistant nickel alloy. With the elemental compositions identical in the content of molybdenum (Mo) and aluminium (Al), identical thicknesses and nanolayer periods of λ, the coatings being studied demonstrated a noticeable difference in wear resistance. Both during the turning of steel and nickel-based alloy, the highest wear resistance was detected for tools with the Zr–ZrN–(Zr, Mo, Al)N coating (the tool life was 3–5 times higher than for uncoated tools). The good wear resistance of the Zr–ZrN–(Zr, Mo, Al)N coating may be related to the optimal combination of hardness and plasticity and the active formation of molybdenum oxide (MoO₃) on the coating surface during the cutting, with good tribological and protective properties.

Objectives: Actuality of the study is based on rapid development of polymer composite materials and their increasingly greater application in space industry. Methods: Consequently this work is focused on optimization of technological parameters of impregnation of load-bearing rods of transformable guy-roped type aerial reflectors made of polymer composites by transfer molding method. The main approach to the study of this problem is simulation of transfer molding process with computer-aided engineering system by the finite element analysis. Findings: Features of simplification of geometric models of power rod elements and simulation of transfer molding process are described. Calculations of impregnation velocity of perform model, impregnation time as well as fields of resin pressure distribution by volume of perform model are carried out. Improvements: According to results of the calculations, type of resin feeding into perform volume is selected.

Algorithmic Approach To The Assessment Automation of The Pipeline Shut-Off Valves Tightness

This article discusses the specific application features of end mills with Ti-TiN-(Ti,Cr,Al)N, Zr-ZrN-(Zr,Mo,Al)N, and ZrHf-(Zr,Hf)N-(Zr,Hf,Cr,Mo,Al)N multilayer nanocomposite coatings during the machining of the Inconel 718 nickel–chromium alloy. The hardness, fracture resistance during scratch testing, structure, and phase composition of the coatings were studied. The tribological properties of the samples were compared at temperatures of 400–900 °C. Tests were conducted to study the wear resistance of the coated end mills during the milling of the Inconel 718 alloy. The wear mechanism of the end mills was studied. It was found that in comparison with the other coatings, the Zr-ZrN-(Zr,Mo,Al)N coating had the highest hardness and the lowest value of the adhesion component of the coefficient of friction at high temperatures. However, the Zr-ZrN-(Zr,Mo,Al)N coating exhibited good resistance to cracking and oxidation during the milling of the Inconel 718 alloy. Based on the above, the Zr-ZrN-(Zr,Mo,Al)N coating can be considered a good choice as a wear-resistant coating for the end milling of the Inconel 718 alloy.

Computational Studies of Connections of Spatial Composite Structures of Space-Rocket Techniques

This review analyzes the problems caused by heavy wear of loaded friction elements of structures, which is typical of almost all industries. This implies the importance of solving problems of increasing their durability. Of particular relevance is the need to solve the problem of improving wear resistance of contact surfaces of specialpurpose shut-off valves, being an irreplaceable component of technical equipment used in the oil and gas industry as well as processing industries, nuclear energy, and medicine. It is shown that the effectiveness of solving problems of increasing durability of equipment is largely associated with additional standard processing of loaded friction elements of such structures, and with the improvement of technologies for increasing wear resistance and strength characteristics of their contact surfaces. The analysis of the possibilities of increasing wear resistance by mechanical methods of surface treatment, as well as by methods of surface modification through various functional coatings has been made. It is substantiated that the vacuum-arc method of ion-plasma spraying of a multilayer nanocomposite coating is the most promising way of creating a functional coating to increase the wear resistance of valves. Widespread industrial introduction of the method of beam surface modification of materials makes it possible to obtain such structural-phase states of materials, which are not possible with traditional methods.