Key Engineering Materials Vol. 685

Abstract: In the present study, the influence of Chromium nitride (CrN) and Titanium nitride (TiN) sublayers on the adhesion of polycrystalline diamond films applied to WC-Co substrates was investigated. CrN and TiN layers were deposited on WC-Co substrates by magnetron sputtering in Ar/N₂ atmosphere. Synthesis of diamond films was conducted in an AC abnormal glow discharge CVD reactor. The phase composition of the films was characterized by small-angle X-ray diffraction (XRD). The adhesion of diamond films was compared by analysis of Rockwell indentation imprints. It was found that TiN does not react with the carbon of the diamond film while CrN almost completely converted into chromium carbide (Cr₃C₂). Adhesion tests showed that the efficiency of these sublayers usage is substantially lower than using a Murakami and HNO₃/H₂O pretreatment.

Abstract: The wear resistance of the coatings on the basis of Cu–Mo–S with a copper friction pair was studied by tribological tests in argon and air environment. Microstructure of the coatings was investigated by transmission and scanning electron microscopy. Fiber-globular structure of the coatings was evaluated. Cu–Mo–S coatings can increase the wear resistance of a copper friction pair in ~ 71.7 and ~ 7.9 times in argon and air atmosphere, respectively. Decrease of friction coefficient of copper friction pair from 0.59 to 0.27 (with coating) has been observed during tribological tests in air environment.

Abstract: The transparent coatings on the basis of Al- Si- N system with high Al content and the opaque Al-Si-N with a low Al content were prepared by impulse magnetron sputtering method. Structural-phase state of the two types of coatings was examined by X-ray analysis. The microhardness was measured by nanoindentation method. The microhardness, the elastic modulus and the coefficient of elastic recovery were determined. Also the optical transmission was measured for all types of samples.

Abstract: Results of structural-morphological studies of platinum-rhodium alloy nanosized powders obtained by method of conductor electric explosion in argon are shown in the paper. Investigation results of specific surface, morphology and structure are given in the article. Optimal modes of explosion are found and described. Methods of transmission electron microscopy, scanning electron microscopy, X-ray phase analysis and BET-method were used to investigate properties.

Abstract: The paper presents the study of the effect of hydrogenation on the mechanical properties of commercially pure titanium. It has been found that the localized deformation zones occurring in the plastically deforming Ti samples are stationary dissipative structures. The kinetics of dissipative structure evolution was studied. The hydrogenation treatment is found to enhance a tendency to strain localization in as-treated material, which affects significantly material strength properties.

Abstract: The paper presents the experimental material on obtaining and researching of three-dimensional composite heat-conducting copper-diamond materials in the system of spark plasma sintering. Earlier [1-5], it was established that in order to achieve the effect of the increased heat conductivity of a composite it is necessary to create the conditions hindering the movement of heat flux on the interface boundary. In this work we have attempted to obtain the material with heat conductivity higher than that of pure copper due to addition of diamond powder and synthesis of the composite in the system of spark plasma sintering. For comparison, we have considered copper and diamond compositions in the ratios of 50/50 and 40/60 correspondingly. The results of the heat conductivity analysis have not exceeded the indices of pure copper; however, according to SEM data, it has been found that at SPS-sintering local domains with enhanced adhesion form on the surfaces of diamonds.

Abstract: Under the method of physical optics, there presented a calculation technique of the Stokes parameters ratios to study the polarization characteristics of lidar returns. An ensemble of preferentially oriented plane crystals is considered as a model medium. The iterative algorithm to estimate the optical properties of the particles and its space orientation using the Stokes parameters ratios is presented.

Abstract: An optical model of medium employing a system of plane particles is presented to study numerically the high-intensity reflected radiant energy. The characteristics of anomalous backscattering of optical radiation are received by the method of physical optics. The calculation results for spectral dependence of backscattering coefficient on microphysical and optical properties of particles are displayed in this work. The informative property of characteristics of specularly reflected radiation was determined to learn the nature of particle matter and their microphysical parameters.

Abstract: The luminescence spectra and luminescence excitation spectra have been investigated in the spectral range of 6.5–4.4 eV. Pulsed cathodoluminescence of LiF-WО₃ and LiF-TiО₂ crystals has been studied in the temperature range of 20–300 K. All LiF crystals doped with metal oxides are found to have similar luminescent properties and identical structure of the luminescence centers. It is assumed that photon and electron bombardment induces excitation of different types of О²⁻ oxygen centers perturbed by impurities and Fe₂О₃, WО₃ and TiО₂ included in the oxygen complexes.

Abstract: This paper is devoted to the consideration of currently available studies on obtaining stimulated infrared emission in structures based on HgCdTe quantum wells. Also analysis and interpretation of discussed experimental results are presented in this article.