Ternary polycrystalline compounds

The chemical bath deposition of polycrystalline, zinc blende HgSe thin films on TO glass from aqueous alkaline medium has been reported [120]. Examples of electrodeposited ternary mercury compounds will be discussed in the next section. 

Epitaxial films frequently have superior characteristics than either polycrystalline or amorphous films. The epitaxial growth concerns a large number of materials silicon, silicon-germanium alloys, III-V compounds, binary and ternary composites, metals, etc. 

FIGURE 11.5 Positive potential scans of methanol oxidation on different platinum surfaces in 0.5 M methanol +1 M sulfuric acid at 0.01 V s-1 (continuous line) bare polycrystalline platinum (dotted line) platinum ruthenium (dash-dotted line) platinum osmium (dashed line) and ternary compound platinum ruthe-nium osmium (obtained by simultaneous spontaneous deposition after 60 s of immersion in a mixed solution). 

The formation of a glass in the arsenic-selenium-copper system is facilitated by the formation of three-dimensional structural units that contain all three components. The structural units formed in the glass evidently have a similar composition and structure to the well-known ternary compound Cu3AsSe4. The increase in the electrical conductivity of the arsenic selenides brought about by the introduction of copper is due to the accumulation of these structural units in the ass. The temperature dependence of the electrical conductivity of glasses with a hi copper content is similar to that of polycrystalline CusAsSei. 

Some examples of the grain-size effect in ceramics are illustrated below Ti3SiC2 was chosen as one exemplar, since this ternary compound exhibits a unique combination of properties. It is a layered material that is as machinable as graphite. At the same time, CG (100-300 pm) samples of Ti3SiC2 have been observed to be damage-tolerant, not susceptible to thermal shock and oxidation resistant. The specimens are fully dense, bulk, single-phase polycrystalline samples of Ti3SiC2. This material exhibits brittle failure characteristics at RT, but is plastic at 1,300 °C with yield points of 300 and 100 MPa under compression and flexure, respectively. 

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