Search results for "hardness"
showing 10 items of 160 documents
Exploring corrosion protection properties of alkyd@lanthanide bis-phthalocyanine nanocomposite coatings
2017
Organic coatings have been widely used to protect carbon steel pipelines from external corrosion; however, they often suffer from permeability and weak adhesion. Here we show that synthetic lanthanide bis-phthalocyanine complexes, LnPc2 (Ln = lanthanide metal, Pc = C32H16N8 denotes the phthalocyanine ligand) can be used to form new nanocomposite coatings to provide corrosion protection to the underlying carbon steel pipelines. Electrochemical studies (EIS and potentiodynamic polarization) showed that the incorporation of LnPc2 compound (PrPc2, SmPc2 and HoPc2) additives with alkyd coating, leads to a significant increase in the corrosion resistance of carbon steel in 0.5 M HCl solution. The…
Spark plasma sintering of zirconia/nano-nickel composites
2015
Open Access
Raman Monitoring of Strain Induced Effects in Mechanically Deposited Single Layer Graphene
2012
Graphene is a two dimensional building block for carbon allotropes of many other dimensionality and shows remarkable electronic and optical properties that attract enormous interest. In order to make graphene useful for real technology, a control of its electronic and mechanical properties is a must. In this respect, a crucial step for the use of graphene layers in device fabrication is the deposition onto suitable substrates, understanding the interaction with them. Micromechanical cleavage of graphite has been used to produce high-quality graphene sheets. The aim of this work is to study the strain effects induced in graphene by the deposition process using Raman spectroscopy and scanning…
Hardening and long-range stress formation in lithium fluoride induced by energetic ions
2003
Abstract LiF crystals were irradiated with Au, Pb, Bi and S ions in the energy range 400–2300 MeV and studied by means of Vickers microindentation. Remarkable hardening effects are observed which depend on the applied fluence and ion species, and correlate with the ion energy loss along the ion path. Structural investigations reveal irradiation-induced stress extending deep into the adjacent non-irradiated crystal and leading to the formation of dislocations. X-ray diffraction measurements of the irradiated crystals show a decrease of the lattice constant indicating the presence of internal stress.
Preliminary corrosion studies of P-91 in flowing lead–lithium with and without magnetic field for Indian lead–lithium ceramic breeder test blanket mo…
2014
To study the corrosion of P-91 (9% chromium and 1% molybdenum) material with lead–lithium (Pb–Li) eutectic, two experiments were carried out in a forced convection loop, at eutectic temperature of 550 °C. The first experiment was carried out at a velocity of 15 cm s−1 for 1000 h and the second experiment, at a velocity of 30 cm s−1 for 2700 h. In both the experiments, P-91 sample coupons were exposed to Pb–Li flow in the presence and absence of magnetic field. Samples were analyzed using an optical microscope, scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). Micro-Vickers hardness testing was also carried out. Dissolution of elements into liquid metal is the main…
Ionizing radiation effects on Non Volatile Read Only Memory cells
2012
Threshold voltage (V-th) and drain-source current (I-DS) behaviour of nitride read only memories (NROM) were studied both in situ during irradiation or after irradiation with photons and ions. V-th loss fluctuations are well explained by the same Weibull statistics regardless of the irradiation species and total dose. Results of drain current measurements in-situ during irradiation with photons and ions reveal a step-like increase of I-DS with the total irradiation dose. A brief physical explanation is also provided.
Radiation-hard semiconductor detectors for SuperLHC
2005
An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 10^35 cm^(- 2) s(- 1) has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 1016 cm 2. The CERN-RD50 project ''Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders'' has been established in 2002 to explore…
The Pion Single-Event Effect Resonance and its Impact in an Accelerator Environment
2020
International audience; The pion resonance in the nuclear reaction cross section is seen to have a direct impact on the single-event effect (SEE) cross section of modern electronic devices. This was experimentally observed for single-event upsets and single-event latchup. Rectangular parallelepiped (RPP) models built to fit proton data confirm the existence of the pion SEE cross-section resonance. The impact on current radiation hardness assurance (RHA) soft error rate (SER) predictions is, however, minimal for the accelerator environment since this is dominated by high neutron fluxes. The resonance is not seen to have a major impact on the high-energy hadron equivalence approximation estab…
The impact of ocean acidification and warming on the skeletal mechanical properties of the sea urchin Paracentrotus lividus from laboratory and field…
2016
Increased atmospheric CO2 concentration is leading to changes in the carbonate chemistry and the temperature of the ocean. The impact of these processes on marine organisms will depend on their ability to cope with those changes, particularly the maintenance of calcium carbonate structures. Both a laboratory experiment (long-term exposure to decreased pH and increased temperature) and collections of individuals from natural environments characterized by low pH levels (individuals from intertidal pools and around a CO2 seep) were here coupled to comprehensively study the impact of near-future conditions of pH and temperature on the mechanical properties of the skeleton of the euechinoid sea …
Mechanical behavior and limits to the microhardness testing of hard multilayer coatings on soft substrates
2000
Multilayer coatings of (Ti, Al) N x , (Ti, C)N x and (Nb, C)N x with bilayer thickness of 0.8-8 nm have been deposited by reactive sputtering on stainless steel substrates. Vickers microhardness measurements in the load range of 3.10 -3 to 1 N were performed using a self-adjusting tester. It has been shown that in order to obtain the true hardness of multilayer coatings on a softer substrate, the indentation depth should not exceed about 10% of the coating thickness. Indentation criteria for polycrystalline, amorphous and nanostructured multilayer coatings are compared. The obtained criterion for multilayer coatings is close to that for amorphous films.