The paper examines the key features of the laser sintering method for compressed ceramic-polymer powder materials, enabling the fabrication of composite films with a high filler content and significant open porosity. The laser parameter limits for the formation of composite films for ceramic-polymer composites with different ceramic fractional compositions are determined. It is shown that at a wavelength of 10.6 μm, films with a thickness of 50 to 150 μm can be produced; a wavelength of 1.06 μm allows only thick layers of several hundred micrometers to be formed. During sintering with radiation at a wavelength of 1.06 μm, extrusion of a portion of the ceramic filler onto the pore surface is observed, while at a wavelength of 10.6 μm, this effect is almost absent. The processes of thermal-oxidative degradation of polyvinylidene fluoride under the action of laser radiation are studied. It is found that under nonequilibrium heating conditions, intermolecular and intramolecular dehydrofluorination processes and the decomposition of molecular chains occur simultaneously; the presence of a ceramic filler intensifies these processes.

We examine the effect of laser shock peening (LSP) without coating by low-energy (0.3 J) pulses on the structure and residual stresses in a deformed AMg6 aluminum alloy with different crystallographic textures prior to and after recrystallization annealing. It is shown that the initial texture of the alloy dramatically affects the profile and depth of residual stresses after LSP. It is found that the depth and profile of compressive residual stress (CRS) in the aluminum alloy depend on the orientation of the crystallographic planes relative to the applied force. The smallest depth and magnitude of CRS are obtained when the slip plane is located perpendicular to the applied force. With a favorable crystallographic texture, the CRS depth increases by 1.5 to 3 times, depending on the laser power density and spot diameter. It can be argued that the crystallographic texture of the LSP-processed (LSPed) alloy is one of the main factors influencing the results of laser shock peening.

We consider the effect of laser shock peening without coating (LSPwC) on the structure and stress state of the AMg6 Aluminum alloy with a thickness from 4 to 14 mm before and after preliminary thermal annealing. The roughness parameters Ra and Rz after LSPwC are determined. The magnitude, depth, and profile of compressive residual stresses (CRS) are found to depend on the thickness of the material and preliminary heat treatment. The layer-by-layer X-ray diffraction analysis shows a correlation between the parameters of the crystal structure and the profile of residual stresses for the processed samples. We find homological distortions of the crystal lattice in the CRS zone and observe the formation of significant (up to - 100 MPa) residual stresses on the unprocessed side of the samples. Also, we determine the surface CRS magnitudes for double unilateral and bilateral processing.

A device for the polarization of polymer films in the electric field of a barrier-type surface corona discharge is described, and the features of its operation are considered. The possibility of obtaining a uniform distribution of the potential of charges deposited on the polymer surface is demonstrated. Using the method of X-ray phase analysis, it is shown that the proposed method of polarization makes it possible to create an electric field on the surface of a composite film of polyvinylidene fluoride + PZT-ceramic, the intensity of which is sufficient to initiate the phase transition α → β in the polymer.

The processes of laser synthesis of films with a thickness of 80-230 μm from polyvinylidene fluoride of various grades are studied. It is established that the range of synthesis modes does not depend on the grades of PVDF. The content of the piezo active β-phase decreases after laser treatment, but the complete transformation of β-> α does not occur. The process of thermos-oxidative degradation after laser treatment is not observed. Under the same treatment conditions, the higher the open porosity coefficient, the lower the polymer melt flow index (MFI). Depending on the MFI of the initial polymer, the selection of laser exposure modes can control the porosity of the films in the range of 26-68%. Keywords: laser treatment, polyvinylidene fluoride (PVDF), porous films, melt flow index.

The microstructure and distribution of residual stresses in the AMg6 alloy after laser shock treatment in the power density range of 1.3–6 GW/cm 2 have been studied. Using X-ray structural analysis, it has been found that, after laser exposure, the size of the coherent scattering regions (CSR) decreases to 60 nm, the value of microstrains increases to 0.0018, and the average dislocation density increases from 6.6 × 10 13 to 3.7 × 10 14 m –2 . Laser shock treatment forms residual compressive stresses to a depth of 1 mm, reaching –128 MPa on the surface of the material.

The microstructure and distribution of residual stresses in AMr6 alloy after the laser shock processing in the range of power density 1—6 GW / cm2 have been studied. By the X-ray diffraction method it was found that domain size decreased up to 60 nm, microstrains increased up to 0,0018 and average dislocation density increased by a factor of 5,5 in comparing with untreated material (3,7×1014 м–2 vs. 6,6×1013 м–2). The laser shock processing generates residual compressive stresses in depth up to 1 mm, with a maximum of –128 MPa on the surface of the material.

The possibility of growing modified polyvinylidene fluoride (PVDF-2M) films by laser sintering is shown. The effect of laser radiation with a wavelength of 10.6 µ m on the polymer structure and the quality of the film sintering is studied.

The results of the studies of laser processing of alkoxide aluminum hydroxides with micrometer and nanometer particle sizes are presented. It is shown that the pseudo-boehmite processing process and phase composition of formed oxides are controlled by particle packing, laser radiation propagation in powder, and specific energy deposition. The main phases formed upon laser heating are γ, α-Al2O3; the content of δ, θ-Al2O3 is low. The minimum corundum crystallite size is ∼50 nm.

X-ray diffraction line profile analysis is adapted to investigate the microstructure of alumina. The structure of electrocorundum and corundum powders produced from pseudoboehmite with submicronic and nanometer-sized particles is analyzed. The lognormal size distribution parameters and their dependence on the conditions of corundum synthesis are determined. The structure of dislocations in corundum with different synthesis prehistories is analyzed, and structural features of the studied material are revealed.

The influence of the operating mode of an X-ray diffractometer on the profile and integral width of instrumental lines was investigated. It was shown that the choice of a function for the best approximation of the instrumental line depends on an angular range of recording. The best approximation functions in different angular ranges were determined. It was shown that the main effect on the instrumental line width is exerted by the dimensions of the input vertical divergence and receiving slits. The criterion of choice of the maximum size of the receiving slit for X-ray tubes with different sizes of the focal spots was experimentally substantiated.

It was shown by X-ray diffraction that the aluminum crystal structure is distorted under conditions of nonequilibrium laser heating, which appears in lowering the lattice symmetry. A method for describing the observed distortions, based on the transition to a new unit cell, was proposed. It was shown that the distorted aluminum crystal structure can be described using the transition from the face-centered cubic cell to the monoclinic body-centered cell. The parameters of the aluminum unit cell after laser irradiation were determined as a = 0.2870 nm, b = 0.2860 nm, c = 0.4060 nm, and β = 90.013° (for the axes of the monoclinic body-centered lattice).

In oxidation of 1,3-dinitro- and 1,3,5-trinitrobenzene acetonate σ adducts (Yanovskii complexes) with sodium, potassium, and tetrabutylammonium cations in acetonitrile and tetrahydrofuran (290-313 K), ion pairs are less reactive than free ions, which is explained by charge redistribution in the ring of the σ adducts, decreasing the electron-donor power of the associated anion. Separation of the apparent rate constants into ionic and ion-pair contributions showed that the reactivity of the ion pairs depends on the radius of their cation. The revealed kinetic regularities are interpreted on the basis of AM1 semiempirical quantum-chemical calculations of the ions and ion pairs with lithium cation.

The conditions of synthesis of a nickel titanium based biocomposite material with hydroxyapatite added to the initial Ni-Ti powder mixture were studied. The material was obtained by a method based on the combination of laser-controlled selective sintering and self-propagating high-temperature synthesis. The data of X-ray diffraction and electron microscopy indicate that the high-rate laser heating induces the interaction of hydroxyapatite with nickel titanium, which results in the formation of additional intermetallic phases (NiTi2, Ni3Ti).

An analysis was made of selective sintering of metal—polymer powder composites by laser radiation with the wavelength 1.06 μm. The optical properties of the composites were investigated and their thermal conductivities were determined. A physical model of the sintering process was developed. This model is capable of predicting the thickness of a monolayer as a function of the composition of the composite and of the laser processing parameters.