Laser surface treatment of different materials influences significantly on the surface morphology, microstructure, and phase components of treated zones. The local temperature conditions, fast melting-fast crystallization, produced during the process is an interesting direction of preparing new ceramic materials in which a controlled inhomogeneous distribution of the impurities, the phases, etc. can be realized. This work is concerned with an experimental investigation of the crystallization, microstructure, and properties induced by a laser beam in a-Al 2 O 3 1na-Cr 2 O 3 pressed powder samples using electron paramagnetic resonance (EPR) spectroscopy and X-ray diffraction methods. During laser irradiation, melting of the sample surface layers takes place. In such a layer, the Al 2 O 3 melt covers the a-Cr 2 O 3 particles. Complete dissolution of a-Cr 2 O 3 in Al 2 O 3 does not occur. During cooling of the sample, crystallization of the a-Al 2 O 3 layer takes place. The crystallized layer shows preferred orientation, which is different in different samples. In the surface layer, the undissolved a-Cr 2 O 3 particles also acquire a preferred orientation, the direction of which does not coincide with the direction of the preferred crystallization of a-Al 2 O 3 . Analysis of changes in the width and the shape of EPR spectra with the increasing concentration of paramagnetic centers under their homogeneous and inhomogeneous spatial distribution in specimens was performed. It is shown that the character of the concentration distribution of chromium impurities in laser-treated a-Al 2 O 3 samples is determined by the diffusion laws and is inhomogeneous.
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 phase formation in the zone of directional laser irradiation of compacted Al2O3–TiO2–Y2O3 mixtures has been investigated. It is established that phase formation is carried out within the framework of binary mixtures Al2O3 – Y2O3 and Y2O3 – TiO2.
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