Diffusion-Controlled Formation of Ti₂O₃ during Spark-Plasma Synthesis

Abstract

The spark-plasma-sintering (SPS) technique has successfully been applied for the single-step direct synthesis of Ti2O3 from a mixture of powders of rutile/anatase with titanium. The components react by diffusion through the grain boundaries, forming several intermediate phases locally. A single-phase material of titanium(III) oxide is obtained in compact bulk form after 180 min of SPS treatment at 1473 K. The electrical and thermal transport properties of such a SPS-prepared material measured in the temperature range between 300 and 800 K reflect the known semiconductor-to-metal transition above 400 K. The observed metallic-like electrical and thermal conductivity above this temperature is in good agreement with previously reported results. A maximum of the thermoelectric figure-of-merit ZT = 0.04 is achieved at 350 K.

A chemists view: Metal oxides with adaptive structures for thermoelectric applications

“…Recently, a homologous series of reduced early titanium oxides , the so‐called Magnéli phases, came into the focus of thermoelectric research . Structurally related to Ruddlesden–Popper phases through the ReO 3 parent structure , they attracted attention during the 70s due to the occurrence of charge density waves in the low temperature regime .…”

“…Although modeling of the electronic structure is difficult because of the large unit cell and disorder, the degree of reduction in the homologous series allows the targeted manipulation and optimization of the electronic transport properties. So far, only a limited number of studies on the high temperature thermoelectric properties of Magnéli oxides of titanium and related composites are available This group of chemically inert and physically compounds has a potential as stable compounds and may close the gap between n‐type and p‐type oxide materials. Some of the most important results are illustrated and compiled in Fig.…”

Manufacture and Testing of Thermoelectric Modules Consisting of BxC and TiOx Elements

“…[36] The components of the starting mixture (TiO 2 and Ti) react at the contact surface only. [36] The components of the starting mixture (TiO 2 and Ti) react at the contact surface only.…”

A Novel Method To Prepare B/N Codoped Anatase TiO2

“…The low photocatalytic efficiency makes it difficult or even nearly impossible to be widely used. [9][10][11][12][13][14][15] Therefore, it is important for TiO 2 to achieve photocatalytic response in a wider range extending to visible light.…”