52,752 research outputs found
Porosity and Micro-Hardness of Shrouded Plasma Sprayed Titanium Coatings
Titanium and its alloys are often used as key materials for corrosion protection. A promising approach to optimize both mechanical properties and corrosion resistance is the use of
coating technologies. In this paper, shrouded plasma spray was used as a useful technology to produce low oxide containing titanium coatings. A solid shroud was used to plasma spray titanium coatings to reduce the oxide content. The titanium coatings were assessed by optical microscope, scanning electron microscopy and Vickers microhardness testing. The results showed that the shrouded titanium coatings exhibited an enhanced microstructure. The presence of the shroud and
shroud gas flow led to a significant reduction in coating porosity because the reduction in air entrainment with the shroud resulted in better heating of the particles. The shrouded titanium coatings had a lower value of Vickers microhardness and a relative lower standard deviation than the air plasma sprayed titanium coatings
Plasma sprayed titanium coatings with/without a shroud
Abstract:
Titanium coatings were deposited by plasma spraying with and without a shroud. The titanium coatings were then assessed by scanning electron microscopy. A comparison in microstructure between titanium coatings with and
without the shroud was carried out. The results showed that the shroud played an important role in protecting the titanium particles from oxidation. The presence of
the shroud led to a reduction in coating porosity. The reduction in air entrainment with t he shroud resulted in better heating of the particles, and an enhanced
microstructure with lower porosity in the shrouded titanium coatings were observed compared to the air plasma sprayed counterpart
Monte-Carlo Simulations of Spin-Crossover Phenomena Based on a Vibronic Ising-like Model with Realistic Parameters
Materials with spin-crossover (SCO) properties hold great potentials in
information storage and therefore have received a lot of concerns in the recent
decades. The hysteresis phenomena accompanying SCO is attributed to the
intermolecular cooperativity whose underlying mechanism may have a vibronic
origin. In this work, a new vibronic Ising-like model in which the elastic
coupling between SCO centers is included by considering harmonic stretching and
bending (SAB) interactions is proposed and solved by Monte Carlo simulations.
The key parameters in the new model, and , corresponding to the
elastic constant of the stretching and bending mode, respectively, can be
directly related to the macroscopic bulk and shear modulus of the material in
study, which can be readily estimated either based on experimental measurements
or first-principles calculations. The convergence issue in the MC simulations
of the thermal hysteresis has been carefully checked, and it was found that the
stable hysteresis loop can be more readily obtained when using the SAB model
compared to that using the Wajnflasz-Pick model. Using realistic parameters
estimated based on first-principles calculations of a specific polymeric
coordination SCO compound, [Fe(pz)Pt(CN)]2HO,
temperature-induced hysteresis and pressure effects on SCO phenomena are
simulated successfully.Comment: 8 pages, 8 figure
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