Structure and properties of non-stoichiometric titanium carbide powder after mechanical treatment

Abstract

Practical significance of nonstoichiometric titanium carbides TiCx in various fields of technology and medicine increase the relevance of the study of both methods used to produce titanium carbide powder and its properties in a wide stoichiometric range. Mechanical treatment is one of the efficient techniques to affect physical and mechanical properties of powder systems. The study investigated the structure, phase composition and parameters of the fine crystal structure of titanium carbide (TiC) powder subjected to mechanical treatment in a ball mill. It is found that at increased duration of milling of the nonstoichiometric titanium carbide powder TiC0.7 the specific surface area of the powder grows from 0.6 to 3.4 m2/g, and the average particle size calculated from it reduces from 2 µm to 360 nm. It is shown that during treatment of the nonstoichiometric titanium carbide TiC0.7 powder, its structural phase state changes. Powder particles consist of two structural components with different atomic carbon-to-titanium ratio: TiC0.65 and TiC0.48. Mechanical treatment of titanium carbide powder decreases microstresses of the TiCx crystal lattice and reduces the CDD size from 55 to 30 nm for the TiC0.48 phase. For TiC0.65 and TiC0.48 phases, increased milling duration acts to decrease the CDD size and to increase the level of the crystal lattice microdistortion. This indicates that, along with powder particle grinding, mechanical treatment provides an increase in particle imperfection.