Alloys lattice structure

The solution of hydrogen in palladium must be considered as a different type of alloy system, because the hydrogen cannot replace palladium in the lattice structure. The fall in susceptibility to zero at a hydrogen-palladium ratio of 0.55 suggests that all the electrons of the hydrogen atoms enter the 4d palladium levels (11). 

Allen reported TEM observations of a nonaligned decomposition products in long-range ordered Fe-Al alloy [22]. Such morphologies are called isotropic spinodal microstructures. Similar structures are observed in Al-Zn and Fe-Cr alloys. Such structures can be produced in systems that are elastically isotropic or in which the lattice constant does not change appreciably with composition. 

Semiconductor alloys The third approach to the extension of the visible-light response of wide band-gap photocatalysts involves making solid solutions between wide and narrow band-gap semiconductors with a similar lattice structure as depicted in Figure 14. 

The objective of this section is to introduce the BFS-based methodology for a detailed study of the most important features of surface alloy formation. The methodology assumes no a priori information on the system at hand. The only input necessary consists of the basic parameterization of the participating elements and lattice structures needed, as described in Sec. 2, and a catalogue of atomic distributions, where each configuration represents a state accessible by the system under study. Each entry in the catalogue is a computational cell popu-... 

Structures of Abnormal Valency or Electron Intermetallic Compounds. We have seen how in many alloy systems the / -. y- and e-phases are based on electron compounds the formula of which differ very widely but which have in common electron atom ratios of 8 2, 21 18 and 7 4. The range of existence of the particular phases is really a range of solid solution in the compound concerned, and this tends to decrease, as it does in primary solid solution, with increase of valency of the second metal. The j3-, y- and -phases have, however, more in common than mere electron concentration, for they have, in addition, the same lattice structure, although the atomic arrangement is usually a purely random one. Thus, the 8 2 / -compound phase is normally body-centred cubic, although it may have a modified cubic structure known as the /3-manganese one the 21 18 y-compound phase, known as the y-brass structure,... 

In a substitutional alloy, atoms of the solute occupy sites in the lattice of the solvent metal (Figure 5.8). To maintain the original lattice structure of the host metal, atoms of both components should be of a similar size. The solute atoms must also tolerate the same coordination environment as atoms in the host lattice. An example of a substitutional alloy is sterling silver (used for silver cutlery and jewellery) which contains 92.5% Ag and 7.5% Cu elemental Ag and Cu both adopt ccp lattices and rn,etai(A-g) rjnet3i(Cu) (Table 5.2). 

A.F. Wells (1984) Structural Inorganic Chemistry, 5th edn. Clarendon Press, Oxford - Chapter 29 provides excellent coverage of metal and alloy lattice types. 

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