Showing papers by "Srinivasa R. Bakshi published in 2007"
TL;DR: In this paper, multiwalled carbon nanotube reinforced UHMWPE composite films were prepared by electrostatic spraying followed by consolidation and X-ray diffraction and differential scanning calorimetry studies showed a decrease in the crystallinity of UH MWPE due to the nature of the fabrication process as well as addition of MWNT.
Abstract: In the present work, multiwalled carbon nanotube (MWNT) reinforced UHMWPE composite films were prepared by electrostatic spraying followed by consolidation. X-ray diffraction and differential scanning calorimetry studies showed a decrease in the crystallinity of UHMWPE due to the nature of the fabrication process as well as addition of MWNT. Tensile test showed an 82% increase in the Young’s modulus, decrease in stress to failure from 14.3 to 12.4 MPa and strain to failure from 3.9% to 1.4% due to 5% addition of MWNT. Raman spectra showed the presence of compressive stresses in the nanotubes. Fracture surface showed presence of pullout like phenomena in the MWNT reinforced film. � 2007 Elsevier Ltd. All rights reserved.
107 citations
TL;DR: Two different methodologies of CNT addition have been adopted in the powder feedstock to assist CNT dispersion in the nano-Al2O3 matrix to improve fracture toughness of the nanocomposites.
Abstract: Al2O3 ceramic reinforced with 4-wt% multiwalled carbon nanotube (CNT) is plasma sprayed for improving the fracture toughness of the nanocomposite coating. Two different methodologies of CNT addition have been adopted in the powder feedstock to assist CNT dispersion in the nano-Al2O3 matrix. First, spray-dried nano-Al2O3 agglomerates are blended with 4 wt% CNT as powder-feedstock, which is subsequently plasma sprayed resulting in the fracture toughness improvement of 19.9%. Secondly, spray dried composite nano-Al2O3 and 4 wt% CNT powder was used as feedstock for attaining improved dispersion of CNTs. Plasma sprayed coating of composite spray dried powder resulted in increase of 42.9% in the fracture toughness. Coating synthesized from the blended powder displayed impact alignment of CNTs along splat interface, and CNTs chain loop structure anchoring the fused Al2O3 melt whereas coating synthesized from composite spray dried powder evinced anchoring of CNTs in the solid state sintered region and CNT mesh formation. Enhanced fracture toughness is attributed to significance of CNT dispersion.
95 citations
TL;DR: In this article, the mean values of elastic modulus and hardness were higher for the MWNT-reinforced coating, while the plasticity index of the coatings was unaffected.
Abstract: Ultrahigh-molecular-weightpolyethylene (UHMWPE) and 5 wt.% multiwalled-carbon-nanotube-(MWNT) reinforced UHMWPE coatings were prepared on a steel substrate by electrostatic spraying. Nanoindentation and nanoscratch tests were performed on the coatings to evaluate the mechanical and wear properties at small length scales. The mean values of elastic modulus and hardness were higher for the MWNT-reinforced coating, while the plasticity index of the coatings was unaffected. The lateral force and coefficient of friction was considerably higher in the case of the MWNT-reinforced coating, indicating an increase in resistance to wear due to the addition of MWNT.
42 citations
TL;DR: In this paper, two different coatings of 1100 aluminium were cold sprayed onto similar substrates, using He and 20N2 (vol.-%) mixture as carrier gases, and three point bend testing was carried out.
Abstract: Two different coatings of 1100 aluminium were cold sprayed onto similar substrates, using He and He–20N2 (vol.-%) mixture as carrier gases. Three point bend testing was carried out. The elastic moduli of the coatings were found to be close to each other and the substrate. The He processed coating showed higher fracture strength which was attributed to the higher degree of strain hardening. The He–20N2 processed coating failed at lower stress owing to its strain relaxed structure. The mode 1 fracture of the coating substrate system was found to be higher for the helium processed coating. The toughness was correlated to the microstructure. The delaminated coating showed a higher degree of brittle failure of the interface for the He processed coating.
17 citations