The influence of Cr-Al-Si-N, DLC-Si, and Cr-Al-Si-N/DLC-Si thin coatings deposited on titanium alloy (Ti-Al-Zr-Sn-Nb system) samples with different surface reliefs on wear resistance under abrasion and fretting conditions was investigated. The influence of coatings on the initial microrelief after finishing milling and lapping with micro-grained abrasive was studied by profilometry. The Martens hardness (H) and the elastic modulus (E) were determined through nanoindentation. The H/E ratio was 0.08, 0.09, and 0.13, respectively. The adhesion bond strength and H/E ratio relationship was revealed using a scratch testing analysis. Volumetric wear after 20 min of abrasive exposure was reduced by 11, 25, and 31 times for Cr-Al-Si-N, DLC-Si, and Cr-Al-Si-N/DLC-Si coatings compared to uncoated ones after milling and by 15, 32, and 35 times after lapping. Volumetric wear under fretting conditions was reduced by 1.8 and 4 times for Cr-Al-Si-N coating after milling and lapping. It was reduced by tens of times for DLC-Si coating and by hundreds of times for Cr-Al-Si-N/DLC-Si coating. The Cr-Al-Si-N/DLC-Si coating (a thickness of 3.1 ± 0.15/2.0 ± 0.1 µm) is characterized by the best combination of hardness (24 ± 1 GPa), elastic modulus (185 ± 8 GPa), and friction coefficient (0.04–0.05 after milling and 0.1 after lapping) and ensures maximum wear resistance under a wide range of loads. The novelty of the work is that those coatings were not practically under study concerning the deposition on the titanium alloy regarding typical mechanical loads such as abrasive and fretting wear but are of interest to the aviation and aerospace industry.

The elemental composition and the morphology of ceramic-like microarc oxidation (MAO) coatings on a zirconium alloy are studied. The coatings are prepared by MAO in electrolytes with addition of aluminum and calcium hydroxide nanopowders. The electrolyte with aluminum hydroxide nanopowder enables preparation of relatively thick (up to 90 μm) and dense coatings composed of both zirconium oxide and oxides of other elements contained in the electrolyte. The electrolyte with calcium hydroxide nanopowder yields thinner MAO coatings that almost completely consist of zirconium oxide.

Методом реакционного магнетронного распыления постоянного тока двух раздельных моноэлементных мишеней Ti и Pb напыляли композитное покрытие состава TiN–Pb на подложку из титанового сплава ВТ6. Исследования проводили при токах на Pb-катоде 0,2 и 0,1 А и двух фиксированных значениях расхода аргона: 6,0 либо 8,5 см3/мин, меняя от опыта к опыту расход подаваемого в камеру азота. Состав покрытий определяли энергодисперсионным анализом. Показано, что количество свинца в покрытиях составляло от 0,5 до 16 мас.% в зависимости от тока на Pb-катоде и расхода реактивного азота. Для каждого режима напыления оценивали микротвердость и износ покрытий. Установлено, что в зависимости от отношения потоков аргона и азота толщина покрытий менялась от 1,9 до 5,2 мкм. Рентгеноструктурным методом исследовали влияние параметров нанесения магнетронных TiN–Pb-покрытий на их структуру и фазовый состав. Выявлено, что при значениях тока на Pb-катоде, равном 0,2 А, покрытие состоит из Pb и PbO, а при токе 0,1 А – из TiN, Pb и PbO. При этом увеличение отношения потоков аргона и азота приводит к росту доли TiN, повышению интенсивности насыщения поверхности титановой подложки азотом, а также увеличению микротвердости и износостойкости. При всех условиях напыления TiN-покрытие характеризуется типичной текстурой (111), интенсивность которой меняется немонотонно.

Solid lubricating composite TiN coatings with Pb additives were obtained on steel and titanium substrates in the process of reactive magnetron sputtering of separate cathodes. Columnar, columnar nanostructured and composite nanostructured TiN coatings with different contents (3–13%) of a lubricating component (Pb) were obtained by deposition onto rotating and stationary substrates. It was found that deposition at a rotating substrate and 3% Pb content in the TiN matrix led to a columnar crystallite coating structure. With an increase in its content to 8%, columnar crystallites in the structure become less pronounced, and the coating becomes columnar nanostructured. In nanostructured composite coating with 12% Pb, the soft component is distributed both in the matrix and in the form of inclusions. XRD analysis of the composite nanostructured TiN–Pb coating indicates a textureless state. In this case, the diffraction lines of all present phases (Pb, PbO, TiN) are characterized by a significant broadening, indicating that the size of the subgrains are in range of 10–20 nm. Tribological tests of the coatings were carried out at room temperature and under conditions of stepwise heating. The nanostructured composite coating showed the best tribological characteristics due to a high Pb content, a relatively high microhardness (817 HV) and a textureless state with a low grain size. This coating had a low friction coefficient (~0.1) over 50,000 test cycles, both at room temperature and under conditions of stepwise heating up to 100 °C and 200 °C.

Thermomechanical action during high-performance diamond grinding of sintered cutting Al₂O₃/TiC and SiAlON ceramics leads to increased defectiveness of the surface layer of the deposited TiZrN and CrAlSiN/DLC coatings. It predetermines the discontinuous and porous coatings and reduces its effectiveness under abrasive exposure and fretting wear. The developed technological approach is based on “dry” etching with beams of accelerated argon atoms with an energy of 5 keV for high-performance removal of defects. It ensures the removal of the defective layer on ceramics and reduces the index of defectiveness (the product of defects’ density per unit surface area) by several orders of magnitude, compared with diamond grinding. There are no pronounced discontinuities and pores in the microstructure of coatings. Under mechanical loads, the coatings ensure a stable boundary anti-friction film between the ceramics and counter body that significantly increases the wear resistance of samples. The treatment reduces the volumetric wear under 20 min of abrasive action by 2 and 6 times for TiZrN and CrAlSiN/DLC coatings for Al₂O₃/TiC and by 5 and 23 times for SiAlON. The volumetric wear under fretting wear at 105 friction cycles is reduced by 2–3 times for both coatings for Al₂O₃/TiC and by 3–4 times for SiAlON.