Том 80, № 12 (2016)

Electron diffraction combined with simultaneous analysis of elemental composition in a transmission electron microscope is used for the first time to investigate La_1–ySr_yF_3–y (0 ≤ y ≤ 0.15) phases with tysonite structure (LaF₃). The two-phase structure of samples with y = 0.10 and 0.15 containing a tysonite matrix and thin interlayers of a phase with a structure similar to that of sphalerite is revealed. The two-phase state is presumably also present in a sample with y = 0.075; however, its content of the platelike phase is too small to be detected via electron diffraction. The presence of the platelike phase in the samples with y = 0.075, 0.10, and 0.15 explains the drop in fluorine ionic conductivity from its maximum at y = 0.05.

The formation of nanoparticles in СZn-Si(100) implanted with ⁶⁴Zn⁺ ions using a dose of 5 × 10¹⁶ cm^–2 and an energy of 50 keV at room temperature with subsequent thermal processing in oxygen at temperatures ranging from 400 to 900°C is studied. The surface topology is investigated with scanning electron (in the secondary emission mode) and atomic force microscopes. The structure and composition of the near-surface silicon layer are examined using a high-resolution transmission electronic microscope fitted with a device for energy dispersive microanalysis. An amorphized near-surface Si layer up to 130 nm thick forms when zinc is implanted. Amorphous zinc nanoparticles with an average size of 4 nm are observed in this layer. A damaged silicon layer 50 nm thick also forms due to radiation defects. The metallic zinc phase is found in the sample after low-temperature annealing in the range of 400–600°C. When the annealing temperature is raised to 700°C, zinc oxide ZnO phase can form in the near-surface layer. The complex ZnO · Zn₂SiO₄ phase presumably emerges at temperatures of 800°C or higher, and zinc-containing nanoparticles with lateral sizes of 20–50 nm form on the sample’s surface.

Lightning inside the chamber of a scanning electron microscope (SEM), caused by electrons being scattering from a sample (and parts of the chamber), is observed and analyzed. These electrons generate the luminescence in a Thornly–Everhart collector. This parasitic effect (artifact) must be considered and eliminated in all experiments with the cathodoluminescent (CL) mode of SEM. A new technique for measuring surface potential on dielectric samples is proposed. It is based on variations in the CL signal during electron irradiation of a sample in SEM.

A hybrid nanoscope is developed for complex investigations of the surfaces and structures of micro- and nanoscale objects. It economically combines the best features of spectral detectors and electronic, X-ray, probe, and optical microscopes. One part of an object can be investigated using different combinations of light, electron beams, X-rays, scanning probes, and spectral detectors.

Structural defects in amorphous and nanocrystalline alloys of the CoP–CoNiP–NiP and CoW‒CoNiW–NiW systems are studied by means of electron tomography. An algorithm and software are developed to optimize the level of binarization of tomographic models used to select objects. Computer simulations show that the distribution of the volume of material density fluctuations is a Pareto distribution. It is established that a modified Pareto distribution describes the experimental distribution of volumes with a smaller error.

Optoacoustic means are used to study the kinetics of laser damage accumulation in potassium chloride crystals. This approach allows us to observe the accumulation of changes in KCl crystals when it is irradiated by a series of laser pulses of subthreshold intensity in a variety of actions (alloying, applying an external electric field, UV illumination). Number of laser pulses N_cr required to destroy a specimen at the same density of radiation power depends on density power I as N ~ I⁻⁴. Results are explained by the formation and accumulation of structural defects during photochemical reactions under the action of laser radiation.

The results from studying the photoelectric properties of CdS films with nanostructured surfaces and synthesized via pyrolysis of thiourea coordination compounds are presented. It is shown that the photocurrent limiting effect is observed in the studied structures at higher intensities of the excitation light. This effect, which is attributable to the optical smoothing of nonuniform barrier relief, could find practical application in optoelectronics.

An investigation of Co₆₉Fe_3.7Cr_3.8Si_12.5B₁₁ amorphous alloy shows that thermally reversible isotropic short-range compositional ordering and clustering can lead to the degradation of hysteretic magnetic properties (HMPs). At temperatures below the Curie temperature (260°С), the degradation of HMPs is caused by thermally reversible directional ordering and reduces the mobility of domain boundaries. Clusterization, a thermally irreversible process observed via small-angle X-ray scatterimg, affects HMPs only during sample annealing immediately after quenching.

Comprehensive microstructure studies of the surfaces of duralumin sheets exposed to an intense microsecond СО₂ laser pulse (Е ~ 500 J) are performed for the first time. The irradiated area is ~100 cm². A pulse with a duration of ~5 μs has an ~200 ns leading peak. Passivated duralumin sheets subjected to pressure and thermal treatment resulting in the formation of Al₂O₃ layers ~7 μm thick are irradiated. Electron and atomic force microscopy, X-ray spectral analysis, and optical profilometry are used in the study. Detected traces of nonequilibrium evaporation contained a polycrystalline aggregate of several stoichiometric and nonstoichiometric phases of aluminum oxide and its compounds with manganese and magnesium.

A comparative study of the structure of joints produced by arc and laser welding with austenitic nitrogen-containing cryogenic Cr–Ni–Mn steel is performed. The dimensions of seams, the dispersity of the structure, and the microhardness in different zones of the welded joints are studied. It is shown that laser welding results in better structure-sensitive characteristics of welded joints than arc welding.

The results from developing the Khirurg (Surgeon) surgical assembly are discussed. The assembly is based on a waveguide diffuse cooled CO₂ laser, excited by a discharge of acoustic-frequency alternating current, and has an average radiation power of up to 40 W. The abilities of this assembly are estimated in terms of surgical practice in general and its competitiveness on the global market.

The effect the thickness of a cartilage plate has on its laser reshaping is studied. The dynamics of heating during laser irradiation is recorded by means of IR radiometry, along with the dynamics of IR laser radiation passed through the cartilage plate. Variation in the cartilage plate’s shape is traced using still and video photography. It is shown that the time needed to attain a stable curvature and the final radius of the cartilage grow along with the cartilage plate thickness.