Fabrication and Thermoelectric Properties of Magneli Phases by Adding Ti into TiO₂

Abstract

In the present study, the TiO2-Ti compacts with Magneli phases TinO2n-1 were fabricated using the mixed powder of TiO2 powder and addition Ti powder by spark plasma sintering (SPS). The composition and the crystal types of Magneli phases TinO2n-1 were examined. The results showed that various Magneli phases TinO2n-1 (single or multi Magneli phases) with the composition of Ti1+yO2-x were obtained. The Magneli phases TinO2n-1 were formed in the transformation from the mother phase rutile TiO2 to TiO with increase in Ti addition fraction. In addition, the thermoelectric properties of the sintered compacts were also measured. The electrical resistivity of the sintered compacts decreased with increase in Ti addition fraction. The thermoelectric performance of the sintered compacts was improved by the formation of Magneli phases TinO2n-1 with the composition of Ti1+yO2-x.

Effect of surface characteristics on the antibacterial properties of titanium dioxide nanotubes produced in aqueous electrolytes with carboxymethyl cellulose

“…The nonstoichiometric oxides are called titanium suboxides or Magnely phases which have the empirical formula Ti n O 2n-1 . The Magnely phases have remarkable properties as high electrical conductivity, high corrosion resistance, and optical properties, among others (Harada, Tanaka, & Inui, 2010;Ioroi et al, 2008;Lu et al, 2011). nanotubes is under discussion some authors propose different explanations based on OH − incorporation (Regonini, Bowen, Jaroenworaluck, & Stevens, 2013), and O 2− concentration gradients (Chen et al, 2009;Wang et al, 2015) which were discussed in our previous work .…”

“…The nonstoichiometric oxides are called titanium suboxides or Magnely phases which have the empirical formula Ti n O 2n‐1 . The Magnely phases have remarkable properties as high electrical conductivity, high corrosion resistance, and optical properties, among others (Harada, Tanaka, & Inui, 2010; Ioroi et al, 2008; Lu et al, 2011). Recently, Jemec Kokalj et al (2019) evaluated the environmental hazard of titanium suboxides on six organisms and two human cell lines.…”

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.…”

Preparation and oxygen sensing properties of Ti 3 O 5 submicron rods

“…In recent years, several methods have been developed to obtain suboxide of titanium such as TiO 2 reduction, chemical vapour deposition, and spark plasma sintering. The reduction method is to reduce TiO 2 using different reducing agent, including carbon or H 2 [5], PVA [6], NH 3 [7] and Ti [8]. The chemical vapour deposition [9] can form the materials mainly containing Ti 3 O 5 and Ti 4 O 7 .…”