The paper presents the results of studies of the thermal stability of titanium hydride and titanium hydride containing a borosilicate framework. It is shown that the presence of chemically attached boron atoms on the surface of titanium hydride particles increases the initial dissociation temperature of titanium hydride. The phase composition and imperfection of titanium hydride crystals in the temperature range of 100-700 °C were studied. An increase in the defectiveness of the structure of a titanium hydride crystal during its heat treatment is shown. Mechanisms for modifying the surface of titanium hydride by surface assembly and the creation of a borosilicate framework have been established. It was shown that the ongoing structural-phase transformations in the borosilicate coating activate solid-phase interactions and contribute to the fixation of borosilicate. Based on the data of thermogravimetric analysis, it was shown that the modification of titanium hydride increases its thermal stability by 185 °C, shifting the onset of dehydrogenation processes to the high-temperature region from 463 °C to 649 °C.
This study aims to address the poor thermal stability of titanium hydride. Surface microstructural observations, differential thermal analysis, and electron-probe analysis of the thermal stability and phase composition measurements of a titanium hydride fraction that was modified by the electrochemical deposition of titanium metal are presented. It is demonstrated that the metallic titanium deposited on the surface of the fraction acts as an effective trap for hydrogen diffusion into the surface layers upon thermal heating. Modification of the surface of the titanium hydride fraction by electrochemical deposition of titanium metal increased its initial temperature of dehydrogenation by 231.8 °C. The concentration of the hydride phase at the surface layer at 500 °C increased to 87.2% due to the structural redistribution of atomic hydrogen and the hydrogenation of metallic titanium at the surface layer.
This work investigates the radiation resistance of a structural material based on modified titanium hydride and a Portland cement in a flux of neutron and γ-radiation. An assessment of the geometric and physicomechanical properties is given, along with the surface structure of irradiated cement composites, and the phase composition of the main hydrosilicates of the hydrated cement matrix during its γ-irradiation. It is shown that the use of a shot of titanium hydride increases the radiation resistance of radiation shielding based on a cement matrix, in comparison with the unmodified shot. A composite based on a modified shot of titanium hydride retains its basic properties after γ-irradiation, at an absorbed dose of up to 10 MGy. At an absorbed dose of 2 MGy in the Portland cement matrix of a composite based on a modified shot of titanium hydride, the formation of suolunite hydrosilicates occurs. It was established using X-ray fluorescence that, in the titanium hydride, a redistribution of the electron density occurs at an absorbed dose of γ radiation of 5 MGy, caused by structural phase changes due to the ongoing dehydrogenation processes.
The properties of various thermal modifications and forms of calcium sulfate and the conditions of their mutual transition are studied. It is established that the mode of heat treatment of gypsum raw materials affects significantly the nature of the subsequent hydration of the gypsum binder. It is established that the values of pH and pCa suspensions of gypsum binders depend on the temperature of heat treatment of natural gypsum, vary over time and characterize the processes occurring during hydration and hardening of gypsum binders. The values of pH and pCa suspensions of gypsum binders can serve as design criteria for innovative multiphase gypsum binders.
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