Papers by Keyword: Multilayer Coating

Abstract: The article presents the investigation of the effect of the modulation period of the nanomultilayer CrN/TiN coatings, deposited by arc-PVD technology, on the coatings' mechanical and tribological properties. The studied modulation period was in the range from 6 to 16.5 nm. The measured coatings hardness was in the range of 26 - 29 GPa, and the plasticity index was 0.07. The tribological properties were measured against Al₂O₃ and ZrO₂ counterparts. The lowest value of wear rate was measured at the CrN/TiN nanomultilayer costing with modulation period of 8.4 nm.

Abstract: The paper outlines two approaches (the ANSYS finite element modeling and the differential scheme of the self-consistency method) to model the mechanical properties of TiAlN multilayer coatings. To validate the experimental results, these findings were compared with the nanoindentation test results for single and multilayer coatings. This work has revealed the effect of Ti/Al ratio on the mechanical properties of multilayer coatings. The given approaches could be applied to calculate, with an acceptable margin of error, the mechanical properties of TiAlN multilayer coatings.

Abstract: Hard multilayer coatings are technologically promising materials for reducing wear of tribological parts. Multilayer coatings with a systematic alternation of the pair [(TiC_x/Ti/C)÷(a-C)] were deposited on stainless and tool steel by the PVD technique. Hardness (H), elasticity modulus (E) and critical cracking load (P_cr) were determined by the nanoindentation method. Nanofrictional wear test was conducted under multipass sliding of a diamond indenter (Ø 50 nm) under constant load. The specific coefficient of nanofrictional wear of [(TiC_x/Ti/C)÷(a-C)]_n with different composition of titanium-containing layers was determined. The nanofrictional wear rate of [(TiC_x/Ti/C)÷a-C]_n depends on the elastic and plastic characteristics of multilayer coating as a whole. Coatings having H³/E² > 0.12 and P_cr > 58 mN demonstrate low wear rate.

Abstract: A focus point in this work was the research of the influence of deposition condition on properties of CrAlC films. CrAlC films were deposited by arc sputtering technique using arc sputtering of Cr-Al target and pulse arc sputtering of graphite target at different frequency. The multilayer [(CrAlC)+(a-C)]_n coatings were also obtained and investigated. Multilayer [(CrAlC)+(a-C)]_n were deposited with a systematic alternation of the pair [(CrAlC)+(a-C)], where a-C is the amorphous carbon layer. The structure, mechanical properties and fracture toughness of CrAlC films depend on pulse frequencies of the graphite sputtering. With increasing pulse frequency, the film structure changes from uniformly amorphous to amorphous with nanograins, the hardness of the films increases, the critical load of crack formation and film peeling tend to decrease. It is shown that a decrease in the thickness of the layers in [(CrAlC)+(a-C)]_n leads to an increase in the crack resistance.

Abstract: Although elastic modulus of ceramic coatings at elevated temperature is difficult to measure, it was evaluated in this work simply by impulse excitation tests based on the relative method that need only the measured moduli of coated sample and substrate. This novel method was demonstrated to be valid not only for the single layer coating but also for multilayer coatings.

Abstract: Multilayer coating onto orthopedic implants has been studied extensively due to their excellence mechanical and biological properties. A multilayer coating was coated onto metal implants to prevent the leaching of metallic ions into human body. This paper aims to study the hardness of multilayer coatings of Chromium (Cr), Chromium Nitride (CrN), Chromium Carbonitride (CrCN) and Zirconium Nitride (ZrN) by Physical Vapour Deposition (PVD). The deposited multilayer coating was characterised by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX). Cr, CrN, CrCN and ZrN have been successfully deposited onto stainless steel substrates by PVD. XRD analysis detected major peak in preferred orientation of (200) and other peaks with (111), (220), (311) for CrN cubic phase. For CrCN, XRD analysis detected only low intensity peaks of Cr₇C₃ and ZrN peaks with preferred orientation of (111), (200) with other peak (220), (311) and (222). Microvickers Hardness results showed an increment in hardness value from substrates with 160HV to 174HV for Cr, 236HV for CrN, 362HV for CrCN, 364HV for ZrN and 370HV for multilayer coatings.

Abstract: Because friction became a more and more important issue regarding its influences on economical trends and technological developments, causing energy waste, pollution and increased costs for production, this research is oriented towards developing new type of coatings (monolayer and multilayer) having dry lubrication properties. Presented work will refer only to friction coefficients variation for tested samples, trying to establish the direct influence of used deposition parameters and settings for obtained analyses results regarding dry lubrication properties and also trying to determine the best recipe for dry lubrication coatings depositions.

Abstract: 45S5 bioactive glass (BG) based multilayer coatings on stainless steel were produced by a combination of electrophoretic deposition (EPD) and layer-by-layer (LbL) deposition. The properties of the multilayer coating were tested with different characterization methods including SEM, FTIR, XRD, laser profilometer and water contact angle measurements. Degradation and in-vitro bioactivity behaviors were tested in simulated body fluid (SBF) over different time periods. The decomposition of the coating was inhibited and the hydroxyapatite (HA) formation after short immersion period (0.5d) was confirmed. At the same time, levofloxacin, used as a model antibiotic, was incorporated into the multilayer structure for antibacterial purpose.

Abstract: In this paper, we consider the possibility of using, in friction pendulum bearings, multilayer friction proof coatings based on polytetrafluoroethylene compounds modified by nanoscale spinels such as magnesium, zinc and chromium. The tribological effect of applying the coating is achieved by formation of a friction transfer layer. For better wear resistance, we applied a multilayer coating with a power frame covered using electrospark coating. We performed an experimental research of bushing samples and various coating fluoroplastic bases. The research on a friction machine “SMT-1” has shown the effectiveness of epoxy fluoroplastic composition as an anti-friction coating in comparison to other types of fluoropolymer bases.

Abstract: The paper presents the investigation results of an opportunity to create a new type membrane with increased characteristics for the pure hydrogen release from hydrogenous gas mixtures. A multilayer coating formed from alternating layers of Nb–Ti and Ti/TiNi on the substrates was used to create hydrogenselective membranes. The substrates of two types were used: plates of porous metal with submicron pore sizes and nickel plates with submicron columnar structure grown on its surface by means of nickel synthesis via a template.