Structure and properties of titanium hydride powder obtained from titanium sponge by SHS hydrogenation

Abstract

The results of the study of the structure and properties of titanium hydride powders obtained from titanium sponge by SHS hydrogenation and mechanical grinding are presented. Hydrogenation was carried out in a reactor at a constant hydrogen pressure of 3 MPa. After passing the combustion wave, the hot titanium sponge was cooled to room temperature in a hydrogenatmosphere. As a result, titanium hydride spongy granules with a hydrogen content of 4.2 wt.% were obtained. Titanium hydride was ground in a ball mill and divided into 4 fractions corresponding to the fractional composition of titanium powder PTK, PTS, PTM and PTOM. Particle size analysis showed that the samples of the PTK and PTOM powders have a narrower particle distribution in comparison with the PTS and PTM ones. Further, obtained powders chemical composition and surface morphology studies were carried out and bulk density, compaction, pycnometric density and specific surface area were determined. According to the chemical analysis results the content of carbon and oxygen impurities decreases during SHS-hydrogenation and the iron content slightly increases during mechanical grinding depending on the grinding time. The study of morphology showed that the hydride titanium particles have an irregular fragmentary shape, such morphology is characteristic of powders obtained by this technology. The surface structure has partially preserved structure of the initial titanium sponge and consists of elongated oriented grains. It is established that with a decrease in the particle size, the bulk density decreases, and the compaction increases. Pycnometric density and specific surface area values are approximately equal for all powder samples.