Nanocrystalline (NC) diamond films are grown by chemical vapor deposition on various single crystal diamond faces. Under conditions of NC diamond growth, the growing filmmorphology is reduced to two ...planes: {100} and {111}. The {100} planes are smooth and homoepitaxial layerby-layer growth occurs on them, whereas the NC film formed by twin crystalliteswith sizes of several tens and hundreds nanometers grows on {111} planes. Nitrogen impurity sharply increases the diamond growth rate.
Mechanical stresses and amorphization of ion-implanted diamond Khmelnitsky, R.A.; Dravin, V.A.; Tal, A.A. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
06/2013, Volume:
304
Journal Article
Peer reviewed
Scanning white light interferometry and Raman spectroscopy were used to investigate the mechanical stresses and structural changes in ion-implanted natural diamonds with different impurity content. ...The uniform distribution of radiation defects in implanted area was obtained by the regime of multiple-energy implantation of keV He+ ions. A modification of Bosia’s et al. (Nucl. Instrum. Meth. B 268 (2010) 2991) method for determining the internal stresses and the density variation in an ion-implanted diamond layer was proposed that suggests measuring, in addition to the surface swelling of a diamond plate, the radius of curvature of the plate. It is shown that, under multiple-energy implantation of He+, mechanical stresses in the implanted layer may be as high as 12GPa. It is shown that radiation damage reaches saturation for the implantation fluence characteristic of amorphization of diamond but is appreciably lower than the graphitization threshold.
Raman spectra of irradiated with fast neutrons or MeV ion-implanted radiation-damaged natural and CVD diamonds and chemically purified detonation nanodiamonds are investigated. The influence of ...radiation damage level and effects of high-temperature annealing on the intensity and spectral shape of the 1640 cm−1 band is studied. It is shown that in radiation-damaged diamonds this band consists of at least six Gaussian peaks, the intensity of which varies one to one both with the level of radiation disordering and the temperature of the subsequent annealing. The "1640" band in radiation-damaged diamonds is completely annealed at temperatures above 1000 °C, while in detonation nanodiamonds annealing up to 1200 °C does not significantly affect its shape and intensity.
Raman scattering is studied in natural diamond crystals with radiation-induced defects produced by implantation of high energy Xe and Kr ions (ion kinetic energy >1 MeV/amu) and by irradiation with ...fast reactor neutrons (kinetic energy >100 keV). Confocal measurements of the Raman spectra along the surface of an oblique section of the ionimplanted diamonds are used to study the radiation damage profile. The evolution of the Raman scattering spectra with depth of the damaged layer in the ion-implanted diamonds, and as a function of annealing temperature of the neutron-irradiated diamond, is determined by spatial localization of phonons in the radiation disordered crystal lattice and by the formation of associations of intrinsic defects in the lattice.
Optical absorption, interference and microscopy studies of diamond samples implanted with light ions (H
+, D
+ and He
+) and annealed at various regimes revealed new features of irradiation-induced ...graphitisation of diamond: ‘low temperature’ graphitisation related to vacancies and the specific mechanism of graphitisation accompanied by blistering in H
+-implanted samples. Migration of radiation damage is discussed in relation to the stability of the graphitised layers.
The paper presents a justification, setting, and results of experiments on the determination of the liquidus temperature for a molten salt comprised of 73LiF–27BeF
2
with plutonium trifluoride, ...considered as the fuel circuit salt of a liquid-salt reactor for burning Np, Am, Cm. The liquidus temperature of the melt was determined using a differential scanning calorimetry method; the plutonium concentration in the samples was controlled by recording the γ‑radiation of plutonium isotopes. According to the results of the studies, the liquidus temperature comprised 600–680 °C across a range of plutonium trifluoride concentrations from 0.1–3 mol.%. According to the performed calculations, in order to transmute 250 kg/year of Np, Am, Cm in an MSR‑T reactor, this restriction on the concentration of actinide fluorides in the fuel salt at its operating temperature in the reactor of 650–750 °C requires 550–660 kg/year of plutonium.
Optical absorption, interference and microscopy studies of diamond samples implanted with light ions (H
+, D
+ and He
+) and annealed at various regimes revealed new features of irradiation induced ...graphitisation of diamond: the “low temperature” graphitisation directly related to vacancies, the specific mechanism of graphitisation accompanied by blistering in H
+ implanted samples and high temperature graphitisation stimulated by residual radiation damage.
Recently, there has been an upsurge in the development of additive technologies, and engineers and scientists are looking for new formulations with which to build relatively small parts and hull ...elements. For the construction of large objects entirely, for example, the hull of a small vessel, and even more so in mass production, it is necessary to maintain a balance of cost, quality, applicability of material, weight and strength characteristics. The most common material in small-scale shipbuilding of recent times is fibreglass based on polyester and epoxy resins. This material, with intensive use of the boat, has a service life of 15-20 years, and with proper care, this period can be extended. Cases made of glass-plastic have the necessary technical characteristics, both in the production of cases of complex geometry and in further operation. Attempts have already been made to create 3D printers in which polyester resins are used as a printing material, but the negative side of this equipment is that there is no reinforcement between the layers, which reduces the strength, and the layer thickness, which significantly increases the printing speed. Based on the experience gained, a material based on polyester resin was proposed, which has reinforcing fibres in its composition, thanks to which it has a pasty consistency, and retains its shape when applied and does not spread.
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