Известия Томского политехнического университета: Инжиниринг георесурсов (May 2019)
Stability of products of combusting in air aluminum nanopowder with titanium and zirconium dioxides to hydrofluoric acid action in reductive media
Abstract
The relevance of the research is related to the need to obtain titanium and zirconium nitrides using less energy-consuming methods, in particular by combustion synthesis of nitrides in the air using aluminum nanopowder as a reductor. The work is devoted to the finding of the optimum conditions ensuring the maximum yield of the nitrides of the group IV B elements. The refractory nitrides are applied as decorative and corrosion-resistant coatings on various products, such as processing tool, machine parts, as dental implants and for souvenirs production. The main aim of the study is to determine the phase composition of the combustion products of the aluminum nanopowder with titanium and zirconium dioxides after their processing by solution of fluoric acid and hydrazine of treatment. The methods used in the study: differential thermal analysis (SDT Q 600, USA), X-ray diffraction (DRON-3.0, Russia) The result. Titanium and the zirconium nitrides obtained by combustion of aluminum nanopowder with dioxides (TiO2, ZrO2) in air are stable during 1 hour in the solution of the fluoric acid and the hydrazine. At longer treatment titanium nitride was preserved and zirconium nitride was dissolved that is caused by the nature of chemical properties of these nitrides. The solution of hydrofluoric acid with hydrazine without oxidizer is not active in the complexation and in transfer to the solution of a-aluminium oxide, titanium dioxide, zirconium dioxide. But at the same time, aluminum and its compounds, including aluminum nitride, were dissolved in this solution. After processing the combustion products of aluminum nanopowder and titanium dioxide mixture for 1 hour with a solution of hydrofluoric acid and hydrazine, the intensity on the X-ray pulses is practically unchanged: titanium nitride - 100 %, a-aluminium oxide - 47,3 %, aluminum nitride - 14,5 % and titanium dioxide - 22,5 %.
