Preparation of TiC powders and coatings by electrodeoxidation of solid TiO₂in molten salts

Abstract

Porous TiC nanoparticles have been synthesised from sintered pellets comprising a powder mixture of TiO 2 and graphite by electrodeoxidation in molten CaCl 2 -NaCl eutectic. Electrolysis was conducted at 850uC in argon at an applied constant voltage of 3?1 V. The formation of TiC from the oxides/C mixture occurred at less cathodic potentials than those for electrodeoxidation of TiO 2 to titanium metal. No titanium metal was observed during electrolysis, as confirmed by XRD. These findings were consistent with the thermodynamic predictions. It was found that CaTiO 3 was formed during electrolysis and all the titanium oxides disappeared after 4 h electrolysis in a eutectic CaCl 2 -NaCl melt at 850uC, leaving CaTiO 3 /C/TiC mixtures behind at the cathode. It was also found that the formed CaTiO 3 was electrodeoxidised to form TiC by prolonged electrolysis. The present results further demonstrated that an adhesive layer of Ti 0?55 C 0?45 was formed on graphite substrates by electrodeoxidation of TiO 2 on the substrates.

Formation and growth mechanism of TiC terraces during self-propagating high-temperature synthesis from a FeTiC system

“…As one of potential and promising materials, TiC has been widely used for high temperature ceramic crucibles in the mechanical industry, cutting cools and reinforcement particles in the composites. The most widely used methods to prepare TiC are the reduction of rutile (TiO 2 ) with carbon [3], mechanical alloying [4], reaction sintering [5] and selfpropagating High-temperature synthesis (SHS) [6][7][8] and so on. Among various methods for producing TiC, SHS technology has attracted intensive interest due to its high purity of the product, low production cost and relative simplicity of the equipment [9].…”

In-situ synthesis of MoSi2 coating on molybdenum substrate by electro-deoxidation of a SiO2 layer in molten salt

“…Meanwhile, functional coatings prepared by the electro-deoxidation method have also been demonstrated [22]. This paper reported the application of the electro-deoxidation method to in situ preparation of MoSi 2 coatings from pre-coated SiO 2 layers on molybdenum substrate.…”

Preparation of niobium carbide powder by electrochemical reduction in molten salt

“…Abdelkader et al [13] investigated the electrochemical synthesis of hafnium carbide powder in molten chloride, and fabricated fully dense monolithic HfC ceramics from the electro-deoxidized product. Yan et al [14] prepared TiC powders and coatings by electro-deoxidation of solid TiO 2 in molten salt. Lang et al [15] obtained Cr 3 C 2 by electrochemical reduction of the self-sintered cathode in molten CaCl 2 .…”