Effects of niobium pentoxide nanoparticles on the tribological properties of electrodeposited ZnNi coatings

Author(s):  
Hema C. R. Moreira ◽  
Jorge A. B. Oliveira ◽  
Neftali L. V. Carreño ◽  
Ricardo M. Silva ◽  
Irene T. S. Garcia ◽  
...  

Abstract Electrodeposited ZnNi coatings are widely used to improve the corrosion resistance of steel substrates, but their tribological properties are also relevant for loaded contacts under relative motion. This work investigates the hypothesis of improving tribological properties of electrodeposited ZnNi coatings via dispersion of niobium pentoxide nanoparticles (1g/L) in the electrolytic bath. The niobium pentoxide nanoparticles were produced via hydrothermal synthesis assisted by microwave. The surface morphology and chemical composition of the coatings were analysed by scanning electron microscopy coupled with X-ray dispersive energy, X-ray diffraction and X-ray photoelectron spectroscopy. The tribological performance of the coatings was assessed using dry reciprocating ball-on-flat tests at normal loads between 3 and 6 N. The use of niobium pentoxide nanoparticles resulted in significantly denser coatings, with some Nb incorporated in the coated surfaces. Under the lowest normal load, all coated specimens showed relatively low friction (~0.2) and negligible damag. As the normal load increased, the coating produced using niobium pentoxide nanoparticles showed stronger adherence, while conventional ZnNi coating showed increased friction and spalling for the highest load. It is believed that the Nb2O5 nanoparticles increased the number of sites for heterogeneous nucleation, refining the microstructure, so that tougher and more adherent coatings were produced.

2017 ◽  
Vol 739 ◽  
pp. 23-29
Author(s):  
Wen Hsien Kao

The main purpose of this study is to research the tribological properties and mechanical properties of diamond-like carbon coating (DLC) used unbalanced magnetron sputtering system (UBMS). The objective is influence of various Zr target current on the properties of coatings, current from 0.0 A to 0.5 A. The cross-section morphology was observed by field emission scanning electron microscopy (FE-SEM). With the increase of the Zirconium targets current, the quantity contained of the Zirconium increases. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were employed to analyze the microstructure properties of the coatings. The nanoindentation tester was used to measure the mechanical properties. Furthermore, the wear tests were achieved through the Schwingung Reibung and Verschliess (SRV) reciprocating wear tester under dry condition. The DLC coating was deposited used 0.4 A Zr target current possessed the lowest I(D)/I(G) ratio, the highest sp3 content and highest hardness. The DLC coating (0.4A) also displayed excellent tibological properties including the lowest friction coefficient, and wear depth.


Author(s):  
C. Muratore ◽  
A. A. Voevodin ◽  
J. J. Hu ◽  
J. S. Zabinski

A hybrid magnetron sputtering/pulsed laser deposition process was used to grow nanocrystalline yttria stabilized zirconia (YSZ) embedded in an amorphous YSZ/metal matrix. This nanocomposite design reduced friction and improved the toughness of YSZ. Films containing both silver and molybdenum exhibited friction coefficients between 0.2 and 0.4 in air (40% relative humidity) against silicon nitride balls at temperatures between 25° C and 700 °C. Additional solid lubricants reduced the friction coefficient to <0.2 for over 10000 cycles at all temperatures. A multilayer film architecture was developed to further enhance the lifetime of the adaptive coatings. Electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy were used to correlate adaptive behavior at different temperatures to the composition and structure of the films.


Author(s):  
Kyriaki Polychronopoulou ◽  
Claus Rebholz ◽  
Nicholaos G. Demas ◽  
Andreas A. Polycarpou ◽  
Lefki Theodorou ◽  
...  

This study describes the correlation between the microstructure, mechanical and tribological properties of Ti1−xCx coatings (with x being in the range of 0–0.5), deposited by reactive magnetron sputtering from a Ti target in Ar/C2H2 mixtures at ∼200 °C. The mechanical and tribological properties were found to strongly depend on the chemical composition and the microstructure present. Very dense structures and highest hardness and elastic modulus, combined with low wear rates, were observed for films with chemical composition close to TiC. X-ray diffraction (XRD) studies showed that the coating deposited at high C2H2 flow rates composed of randomly oriented TiC crystallites. Morphological investigations by scanning electron microscopy (SEM) indicate that the morphology is strongly dependent on the carbon content of the coating. Coatings composition and bonding environment was investigated using X-ray photoelectron spectroscopy (XPS). Both the mechanical properties and tribological performance of the coatings were found to be dependent on carbon content.


2014 ◽  
Vol 789 ◽  
pp. 455-460 ◽  
Author(s):  
Bin Deng ◽  
Jun Fei Pei ◽  
Ye Tao

Ion implantation is an effective method to enhance hardness and wear resistance of the TiAlN coatings. In this paper, Nb and C ions are co-implanted into TiAlN coatings deposited by Magnetic Filter Arc Ion Plating (MFAIP), using a Metal Vacuum Vapor Arc (MEVVA) ion source implantor with doses of 1×1017and 5×1017ions/cm2. The microstructure, chemical composition, mechanical and tribological properties of Nb+C-implanted TiAlN coatings have been investigated by glancing incidence X-ray diffraction, X-ray photoelectron spectroscopy, nanoindentation test and SRV friction & wear tester, respectively. The results showed that the NbN and TiC phases could be detected both from the XRD and XPS profiles of as-prepared films. Nb and C ion implantation could improve the hardness, plastic deformation resistance and wear behavior of TiAlN coatings due to the energetic Nb and C ion bombardment and the formation of NbN and TiC phases.


2012 ◽  
Vol 229-231 ◽  
pp. 134-137
Author(s):  
Deng Xu ◽  
Ning Li ◽  
Ji Jie Ma ◽  
Guang Ming Cheng ◽  
Lin Lin Wang

The self-lubrication Ni-P/PTFE co-coatings were obtained by chemical plating. The tribological properties of the co-coating were carried on by the MM-200 type abrasion, and the microstructure and compounds of this composition and surface morphology were described by using X-ray diffraction and scanning electron microscope separately. The Ni-P/PTFE co-coating still had a low friction coefficient and good wear resistance. This was due to the PTFE material structure with the twisted chain, helical characteristics of carbon nanotubes, and the hexagonal structure in connection with many unusual mechanical and chemical properties.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2049
Author(s):  
Julio Caicedo ◽  
Neufer Bonilla ◽  
Willian Aperador

The aim of this work is the improvement of the electrochemical behavior of industrial steel using [CoN/AlN]n multilayered system via reactive Pulsed Laser Deposition (PLD) technique with a Nd: YAG laser (λ = 1064 nm) on Silicon (100) and AISI 302 steel substrates. In this work was varied systematically the bilayer period (Λ) and the coatings were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and the chemical composition was determined by means of X-ray photoelectron spectroscopy (XPS). The maximum corrosion resistance for the coating with (Λ) equal to 34.7 nm, corresponding to n = 30 bilayered. The polarization resistance and corrosion rate were around 7.62 × 105 kOhm × cm2 and 7.25 × 10−5 mm/year, these values were 6.3 × 105 and 78.6 times better than those showed by the uncoated 302 stainless steel substrate (1.2 kOhm × cm2 and 0.0057 mm/year), respectively. The improvement of the electrochemical behavior of the steel 302 coated with this [CoN/AlN]n can be attributed to the presence of several interfaces that act as obstacles for the inward and outward diffusions of Cl− ions, generating an increment in the corrosion resistance. The electrochemical results found in the [CoN/AlN]n open a possibility of future applications in mechanical devices that require high demands in service conditions.


2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 581
Author(s):  
Gajanan S. Ghodake ◽  
Surendra K. Shinde ◽  
Ganesh D. Saratale ◽  
Rijuta G. Saratale ◽  
Min Kim ◽  
...  

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.


Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 937
Author(s):  
Yingying Hu ◽  
Md Rasadujjaman ◽  
Yanrong Wang ◽  
Jing Zhang ◽  
Jiang Yan ◽  
...  

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.


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