Browsing by Author "Rashmi B. Rastogi"

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Evaluation of antiwear activity of substituted benzoylhydrazones and their copper(ii) complexes in paraffin oil as efficient low SAPS additives and their interactions with the metal surface using density functional theory
(Royal Society of Chemistry, 2015) Vinay Jaiswal; Shraddha R. Gupta; Rashmi B. Rastogi; Rajesh Kumar; Vinod P. Singh
Sulfur, phosphorus and halogen-free benzoylhydrazones of the formula (HL) [where HL = acetophenonebenzoylhydrazone, H-Abh; and salicylaldehydebenzoylhydrazone, H-Sbh] and their copper(ii) complexes (CuL2) have been synthesized and characterized by FT-IR, NMR spectroscopy and Mass spectrometry. The antiwear performance of these compounds as antiwear additives in paraffin oil has been evaluated using a four-ball tester at an optimized concentration of additives (1% w/v) by varying the load for 30 min test duration and by varying the test durations at 392 N load. Various tribological parameters such as mean wear scar diameter (MWD), mean wear volume (MWV) and wear rates show that ligands and the conventional zinc dibutyldithiophosphate (ZDDP) effectively enhance the antiwear properties of the base lube and possess high load bearing ability. The ligand H-Sbh shows much better antiwear efficiency than H-Abh. Upon complexation the efficiency has increased tremendously in the both cases following the same order as the ligands thereof. The surface topography of the wear track has been studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) at various test conditions. The AFM and SEM micrographs of wear scar lubricated with copper complexes at different conditions show a drastic decrease in surface roughness in comparison to ZDDP/ligands/paraffin oil alone. The enhanced antiwear behavior of copper complexes is attributed to the in situ formation of a tribofilm under sliding contact which eventually leads to energy saving and prevents material loss. Tribochemistry of the worn surface has been investigated using X-ray photoelectron spectroscopy (XPS) which shows that the protective tribofilm/s is composed of CuO, Cu2O, nitrogen in the form of -NC/-N-C-, adsorbed carbon in the form of -C-C-/-C-H, -C-O- moieties and Fe2O3 and/or Fe3O4. Theoretical calculations based on density functional theory (DFT) for the interactions of different additives with the metal surface strongly match with the observed experimental results. Copper strip corrosion tests show non-corrosive behavior of the additives. These additives also show non-corrosive behavior towards AISI 52100 steel in paraffin oil. © 2015 The Royal Society of Chemistry.
Evaluation of Tribological Properties of Sulfur- and Phosphorous-Free Quinolinium Salts and Their Correlation with Quantum Chemical Parameters
(Taylor and Francis Inc., 2017) Kalyani; Vinay Jaiswal; Rashmi B. Rastogi; Devendra Kumar; Praveen Singh
For developing antiwear additives with high efficiency but with low sulfated ash, phosphorous, and sulfur (SAPS), N-substituted quinolinium halides, [DIP-Q]+Br−[DIP-Q=1-(3-(1,3-dioxoisoindolin-2-yl)propyl)quinolon-1-ium], [DIE-Q]+Br−[DIE-Q=1-(3-(1,3-dioxoisoindolin-2-yl)ethyl)quinolon-1-ium], [P-Q]+I−[P-Q=propylquinolon-1-ium], and [M-Q]+I−[M-Q=methylquinolon-1-ium] have been prepared and characterized by1H- and13C-NMR spectroscopic techniques. The tribological performance of these quinolone-based quaternary salts as antiwear additives in paraffin oil has been assessed on a four-ball test rig. The observed results have been compared with those of zinc dialkyldithiophosphate (ZDDP), a high SAPS additive. The tribotesting of these additives has been performed using 1% w/v additives concentration at different loads and times. The potential of these compounds as antiwear additives is evident from their observed tribological data: mean wear scar diameter (MWD), friction coefficient (µ), mean wear volume (MWV), and wear rates. All of the quinolinium derivatives prove to be better antiwear additives than ZDDP. Among the tested synthesized compounds, [DIP-Q]+Br−exhibits the best tribological behavior followed by [DIE-Q]+Br−, [P-Q]+I−, and [M-Q]+I−. The surface topography of worn surface studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that surface roughness is reduced to a greater extent in case of quinolinium derivatives than lubrication with ZDDP or base oil alone. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analysis of worn surfaces in the presence of quinolinium additives shows that the tribofilm is composed of FeBr3, Fe3O4, and organic compounds containing carbonyl and imine bonds. Theoretical investigations using quantum chemical calculations are indicative of significant chemical interactions of these quinolinium additives with metal surfaces, which is strongly supported by the observed experimental data. © 2017 Society of Tribologists and Lubrication Engineers.
Quantum chemical calculation studies for interactions of antiwear lubricant additives with metal surfaces
(Royal Society of Chemistry, 2014) Vinay Jaiswal; Rashmi B. Rastogi; Jiya L. Maurya; Praveen Singh; Ashish K. Tewari
Theoretical calculations based on density functional theory (DFT) have been performed to correlate experimentally observed antiwear properties of Schiff base lubricant additives derived from condensation of salicylaldehyde with N-phenylthiosemicarbazide, [(E)-1-(2-hydroxybenzylidene)-4- phenylthiosemicarbazide; H2STC-Ph], N-p-tolylthiosemicarbazide [(E)-1-(2-hydroxybenzylidene)-4-p-tolylthiosemicarbazide; H2STC-p- MePh] and N-(4-chlorophenyl)thiosemicarbazide, [(E)-1-(2-hydroxybenzylidene)-4- (4-chlorophenyl)thiosemicarbazide; H2STC-p-ClPh] with their chemical structure. antiwear properties have been discussed on the basis of the interactions between the additive molecules and the metal surface. In order to compare the antiwear behavior of different additives, various parameters such as frontier molecular orbital energy EHOMO (Energy of Highest Occupied Molecular Orbital), ELUMO (Energy of Lowest Unoccupied Molecular Orbital), the energy gap (ΔE), mutual orbitals' interactions between additive molecules and metal surface (ΔE1 & ΔE 2), global properties (hardness and softness) and the dipole moment have been calculated and correlated with the respective energies of the metal surface. The quantum chemical calculations (QCC) have shown that the wear-reducing behavior of Schiff bases increases with an increase in E HOMO, decrease in ELUMO, decrease in the energy gap between ELUMO and EHOMO and increase in the dipole moment of the additives. The results obtained by quantum chemical calculations are in good agreement with the experimental results. This journal is © the Partner Organisations 2014.
Synthesis, Characterization, and Tribological Evaluation of TiO2-Reinforced Boron and Nitrogen co-Doped Reduced Graphene Oxide Based Hybrid Nanomaterials as Efficient Antiwear Lubricant Additives
(American Chemical Society, 2016) Vinay Jaiswal; Kalyani; Sima Umrao; Rashmi B. Rastogi; Rajesh Kumar; Anchal Srivastava
The microwave-synthesized reduced graphene oxide (MRG), boron-doped reduced graphene oxide (B-MRG), nitrogen-doped reduced graphene oxide (N-MRG), boron-nitrogen-co-doped reduced graphene oxide (B-N-MRG), and TiO2-reinforced B-N-MRG (TiO2-B-N-MRG) nanomaterials have been synthesized and characterized by various state-of-the-art techniques, like Raman spectroscopy, powder X-ray diffraction, scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the tribological properties of prepared nanomaterials as antiwear additives in neutral paraffin oil have been evaluated using a four-ball machine at an optimized additive concentration (0.15% w/v). The tribological parameters, like mean wear scar diameter, coefficient of friction, and wear rates, revealed that these nanomaterials have potential to be developed as environmentally friendly sulfated-ash-, phosphorus-, and sulfur-free antiwear lubricant additives. The friction- and wear-reducing behavior of MRG increased upon successive doping of nitrogen, boron, and both nitrogen and boron. Among these additives, B-N-co-doped MRG shows superior tribological behavior in paraffin base oil. Besides this, the load-carrying properties of B-N-co-doped MRG have significantly improved after its reinforcement with TiO2 nanoparticles. A comparative study of the surface morphology of a lubricated track in the presence of various additives has been assessed by SEM and contact-mode atomic force microscopy. The X-ray photoelectron spectroscopy studies have proved that the excellent lubrication properties of TiO2-B-N-MRG are due to the in situ formation of a tribofilm composed of boron nitride, adsorbed graphene layers, and tribosintered TiO2 nanoparticles during the tribocontact. Being sulfur-, halogen-, and phosphorus-free, these graphene-based nanomaterials act as green antiwear additives, protecting interacting surfaces significantly from wear and tear. © 2016 American Chemical Society.
Tribological studies of stearic acid-modified CaCu2.9Zn 0.1Ti4O12 nanoparticles as effective zero SAPS antiwear lubricant additives in paraffin oil
(2014) Vinay Jaiswal; Rashmi B. Rastogi; Rajesh Kumar; Laxman Singh; K.D. Mandal
Stearic acid modified ceramic nanoparticles SCCZTO-6 h, SCCZTO-8 h and SCCZTO-12 h of average sizes 60, 80 and 90 nm were prepared from CCZTO-6 h, CCZTO-8 h and CCZTO-12 h respectively (where CCZTO represents CaCu 2.9Zn0.1Ti4O12; 6 h, 8 h and 12 h are the sintering times). The SCCZTO nanoparticles have been characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Tribological behavior of these nanoparticles in liquid paraffin oil has been evaluated using a four-ball lubricant tester and compared with conventional high SAPS containing zinc dialkyldithiophosphates (ZDDP). All antiwear tests have been performed using an optimized concentration of the SCCZTO nanoparticles (1% w/v) by varying the load for a 30 min test duration and by varying the test durations at 392 N load. Various tribological parameters such as mean wear scar diameter (MWD), friction coefficient (μ), mean wear volume (MWV), running-in, steady-state and overall wear rates show that all the SCCZTO nanoparticles act as efficient antiwear additives and possess a high load carrying capacity. The best tribological behavior is shown by SCCZTO-6 h, followed by SCCZTO-8 h and then SCCZTO-12 h. The surface morphology and roughness of the wear scar have been studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) respectively. AFM and SEM micrographs of the wear scar in the presence of SCCZTO-6 h and SCCZTO-8 h at 392 N applied load for a 90 min test duration show a drastic decrease in surface roughness. Energy-Dispersive X-ray (EDX) analysis of the worn surface under similar experimental conditions in the presence of SCCZTO-6 h nanoparticles exhibits the presence of calcium, copper, zinc, titanium and oxygen on the worn steel surface indicating tribosinterization and/or adsorption of the additive on the rubbing surface resulting in the formation of a strong tribofilm. X-ray Photoelectron Spectroscopy (XPS) of the tribofilm shows the presence of CaO, CuO, Cu2O, TiO2, Fe2O3 and adsorbed carbon in the form of-C-C-and-C(O)O-moieties. © 2013 The Royal Society of Chemistry.