Magneli phases

New electrodes based on conducting ceramics, such as Ti407/Ti509 (Magneli phase suboxides) are black, more conductive than graphite, and highly cor-... 

The modern material Ebonex is a mixture of substoichiometric titanium oxides Ti40y, TisOg. .. Tin02n-i ( Magneli phases [32]). It offers a unique combination of electrical conductivity and corrosion resistance. Primarily, Ebonex is produced as a powder. As is usual for ceramics, the ready-formed material is hard and brittle, the possibilities of machining are restricted (diamond tools). 

It has been well established that there is a series of compounds (homologous series) expressed by the general formula V O2 i (n = 3,4,..., 9) between VjOj and VjO, called the Magneli phase. These compounds are non-stoichiometric compounds derived from extended defects (see Section 2.2.1). We describe a study on the phase diagram of this system, carried out by controlling the oxygen partial pressure. 

Graves et al. showed that the current efficiency for ozone evolution on Pb02-plated Ebonex (conducting ceramic material composed of Magneli phase titanium... 

Fig. 2. Phase diagram of the Ti-0 system re-drawn from ref. [3]. The region Ti203-Ti02 contains Ti203, Ti305, seven discrete phases of the homologous series Tin02n-i (Magneli phases), and Ti02. See ref. [3] for a more detailed description.

Ebonex is a conducting ceramic material mainly composed of the Magneli-phase titanium oxides, Ti407 and TisOg, resistant to anodic corrosion in a wide range of media. Electrodeposition of a metal changes the low electron transfer rates of the ceramic material to that of the bulk metal [169]. 

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