Monitoring of the morphologic reconstruction of deposited ablation products in laser irradiation of silicon

Using electron microscopy, atomic force microscopy, X-ray microanalysis, and IR spectroscopy, it was established that, in the regime of continuous laser irradiation of silicon at P = 170 W in different gaseous atmospheres with an oxygen impurity, SiOx composite films with a complex morphology form. The main components of ablation products are clusters that form during flight of ablation products and as a result of separation of SiOx-clusters from the zone of the irradiation channel. The roughness and density of the films depend on the heating temperature of the target surface and the type of deposited clusters

The layer by layer selective laser synthesis of ruby

In the work, features of the layer-by-layer selective laser synthesis (SLS) of ruby from an Al2O3-Cr2O3 mixture are considered depending on the irradiation power, the laser beam traverse speed, the height and amount of the backfill of powder layers. It has been established that, under irradiation, a track consisting of polycrystalline textured ruby forms. The morphology of the surface of the track and its crystalline structure are determined by the irradiation conditions

Features of formation of composite ceramics from SiC-Si-Mo at high pressure

SiC-based composite ceramics were investigated by X-ray diffraction, electron microscopy and electron-probe X-ray microanalysis. It is established that, depending on the composition of the initial powder mixtures, at T = 1500-1800°C and P = 4 GPa, different types of composite ceramics formed. Ceramics obtained from mixtures with CSiC ≥ 50 wt. % contains SiC, Si, and Mo. Ceramics on the base of SiC-MoSi2 was obtained from mixtures with CSiC < 50 wt.%

Electron paramagnetic resonance in the research of defect formation and thermal processes during grinding of ZnO powders

This work shows some possibilities for using electron paramagnetic resonance in an experimental study of the role of mechanothermal effects in the formation of defect structures in dispersed systems during prolonged mechanical treatment of ZnO powders. The use of EPR for this purpose is based on the known fact that initiation of a number of paramagnetic centers occurs during mechanical treatment of some materials. Such centers can serve as EPR-sondes of different thermal processes appearing during mechanical treatment of systems containing ZnO

Structural-phase transformations in bentonite after acid treatment

The methods of X-ray diffraction, Fourier transform infra-red spectroscopy (FTIR), X-ray microanalysis, electron microscopy, BET and cation exchange capacity (CEC) were used for investigation of the structural-phase transformations in bentonite under the influence of hydrochloric acid and temperature treatment (100-800ºC). It is established that in HCl medium during temperature treatment, dehydration and dehydroxilation of montmorillonite occur. The presence of gypsum and barium chloride results in an intercalation of interlayer space of montmorillonite by Ca and Ba ions Temperature treatment of intercalated montmorillonite leads to the formation of pores