“…This may be related to the fact that the lowest bias level associated with the lowest coating integrity favors coating detachment during wear and the loose rolling particles within the contact zone reduce the friction between coating and cylinder liner. Despite this, all conducted wear tests presented values of CoF compatible or inferior to literature values for CrN-based coatings in engine operation 45 – 49 . Figure 6 CoF evolution during wear tests for the multilayer coatings produced using different substrate bias potential.…”
Section: Resultssupporting
confidence: 44%
“…13 . Although the samples deposited using 0.5 and 1 rpm showed a less steep increase in CoF along time and stabilized in lower values (about 0.115 CoF) in comparison with 1.5 and 2 rpm, all coatings presented CoF correspondent to state-of-the-art CrN-containing coatings in the literature and therefore are candidates for piston ring applications 45 – 49 . Figure 13 CoF evolution during wear tests for the multilayer coatings produced using different carousel rotation speeds.…”
A hybrid magnetron sputtering process (dcMS/HiPIMS) was developed to manufacture nanostructured CrN/Cr1-xAlxN multilayers, motivated by improving the low-emission efficiency when applied on gas-nitrided diesel piston rings of a next-generation of combustion engines. In order to improve the mechanical, tribological, and corrosion behavior of the multilayers, the hybrid dcMS/HiPIMS process was designed by selecting the optimal sputtering procedure applied to AISI 440 base steel. The effect of substrate bias and carousel rotational speed on the phase composition, crystallographic texture, residual stresses, surface roughness, coating periodicity and densification, instrumented hardness, elastic modulus, as well as wear and corrosion resistance was determined. The results have demonstrated that hybrid magnetron sputtering produces multilayers with a superlattice structure, which outperforms commercial PVD coatings of CrN for diesel piston rings manufactured by cathodic arc evaporation. Also, multilayer periodicities in the range of 5 to 10 nm yield the best tribological performance under bench tests for the piston ring/cylinder liner system.
“…This may be related to the fact that the lowest bias level associated with the lowest coating integrity favors coating detachment during wear and the loose rolling particles within the contact zone reduce the friction between coating and cylinder liner. Despite this, all conducted wear tests presented values of CoF compatible or inferior to literature values for CrN-based coatings in engine operation 45 – 49 . Figure 6 CoF evolution during wear tests for the multilayer coatings produced using different substrate bias potential.…”
Section: Resultssupporting
confidence: 44%
“…13 . Although the samples deposited using 0.5 and 1 rpm showed a less steep increase in CoF along time and stabilized in lower values (about 0.115 CoF) in comparison with 1.5 and 2 rpm, all coatings presented CoF correspondent to state-of-the-art CrN-containing coatings in the literature and therefore are candidates for piston ring applications 45 – 49 . Figure 13 CoF evolution during wear tests for the multilayer coatings produced using different carousel rotation speeds.…”
A hybrid magnetron sputtering process (dcMS/HiPIMS) was developed to manufacture nanostructured CrN/Cr1-xAlxN multilayers, motivated by improving the low-emission efficiency when applied on gas-nitrided diesel piston rings of a next-generation of combustion engines. In order to improve the mechanical, tribological, and corrosion behavior of the multilayers, the hybrid dcMS/HiPIMS process was designed by selecting the optimal sputtering procedure applied to AISI 440 base steel. The effect of substrate bias and carousel rotational speed on the phase composition, crystallographic texture, residual stresses, surface roughness, coating periodicity and densification, instrumented hardness, elastic modulus, as well as wear and corrosion resistance was determined. The results have demonstrated that hybrid magnetron sputtering produces multilayers with a superlattice structure, which outperforms commercial PVD coatings of CrN for diesel piston rings manufactured by cathodic arc evaporation. Also, multilayer periodicities in the range of 5 to 10 nm yield the best tribological performance under bench tests for the piston ring/cylinder liner system.
“…The coating samples deposited at 0.6-2.8 kW displayed poor wear resistance due to weaker crack resistance and higher surface roughness, whereas the highly dense and smooth surface coatings deposited at 0.6-2.0 kW exhibited improved wear resistance. To compare the microstructure and morphologies of CrN coatings, Ferreira et al [77] developed two different coatings under varying process conditions of N2 gas flow, partial pressure, and bias voltage. With a low N2 gas flow and partial pressure with a higher bias voltage, a highly dense, void free, enhanced hardness microstructure coating with low friction (0.15) and wear loss was achieved.…”
Section: Significance Of the Structural And Mechanical Properties Of ...mentioning
Hard and wear-resistant coatings created utilizing physical vapor deposition (PVD) techniques are extensively used in extreme tribological applications. The friction and wear behavior of coatings vary significantly with temperature, indicating that advanced coating concepts are essential for prolonged load-bearing applications. Many coating concepts have recently been explored in this area, including multicomponent, multilayer, gradient coatings; high entropy alloy (HEA) nitride; and functionally modified coatings. In this review, we highlighted the most significant findings from ongoing research to comprehend crucial coating properties and design aspects. To obtain enhanced tribological properties, the microstructure, composition, residual stress, hardness, and HT oxidation resistance are tuned through doping or addition of appropriate materials at an optimized level into the primary coatings. Such improvements are achieved by optimizing PVD process parameters such as input power, partial pressure, reactive gas flow rates, substrate bias, and temperature. The incorporation of ideal amounts of Si, Cr, Mo, W, Ag, and Cu into ternary and quaternary coatings, as well as unique multilayer designs, considerably increases the tribological performance of the coatings. Recent discoveries show that not only mechanical hardness and fracture toughness govern wear resistance, but also that oxidation at HT plays a significant role in the lubrication or wear failure of coatings. The tribo-induced metal oxides and/or Magnéli phases concentrated in the tribolayer are the key governing factors of friction and wear behavior at high temperatures. This review includes detailed insights into the advancements in wear resistance as well as various failure mechanisms associated with temperature changes.
“…As for coatings, developments have led to the frequent use of hard ceramic coatings deposited by Physical Vapor Deposited (PVD), such as CrN, as it combines satisfactory tribological properties with high hardness, and corrosion resistance at high temperatures, with low production costs, which is a determinant for large-scale applications [5].…”
Piston rings (PR) are known for almost a quarter of the friction losses in internal combustion engines. This research work aims to improve the tribological performance of PR by a recently developed variant of Diamond-like Carbon (DLC) coatings deposited in a mixture of Ar and Ne plasma atmosphere (Ne-DLC) by high-power impulse magnetron sputtering (HiPIMS). For the benchmark, the widely used Chromium Nitride (CrN) and DLCs deposited in pure Ar plasma atmosphere (Ar-DLC) were used. The tribological tests were performed on a block-on-ring configuration under different lubrication regimes by varying temperatures and sliding speeds. The analysis of the results was performed by Stribeck curves corresponding to each sample. An improvement of the tribological performance was observed for Ne-DLC films by up to 22.8% reduction in COF compared to CrN in the boundary lubrication regime, whereas, for the Ar-DLC film, this reduction was only 9.5%. Moreover, the Ne-DLC films achieved ultralow friction of less than 0.001 during the transition to a hydrodynamic lubrication regime due to better wettability (lower contact angle) and higher surface free energy. Increasing the Ne up to 50% in the discharge gas also leads to an increase of hardness of DLC films from 19 to 24 GPa.
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