Alloy solid solutions

The distinction between the two classes of materials considered in this Section per tains to the presence or absence of mixing at the molecular level. Thus in alloys, solid solutions of two or more semiconductors are formed where the lattice sites are interspersed with the alloy components. Semiconductor alloys, unlike their metallic counterparts, have a much more recent history and their development driver has been mainly optoelectronic (e.g., solid state laser) applications. In mixed semiconductor composites, on the other hand, the semiconductor particles are in electronic contact but the composite components do not undergo mixing at the molecular level. 

The nature of alloys. Homogeneous and heterogeneous alloys. Solid solutions, intermetallic compounds. The phase rule, P - - P = C 2 number of phases, variance, number of components of a system in equilibrium triple point. Phase diagrams of binary systems eutectic mixture eutectic point. The systems As-Pb, Pb-Sn, Ag-Au, Ag-Sr. 

The use of mechanical milling is also a suitable method for powder preparation. The feature of this procedure is to obtain powders of small crystallite size of a few nanometers with a high concentration of lattice defects. There are many mechanochemical studies on the synthesis of alloys, solid solutions, nanophasc materials, and intermetallic compounds. Of course, the mechanical alloying also has been applied to prepare mixed oxides containing cerium oxide to enhance catalysis, such as CeOj-TbO, CeOj-HfOj, Ce02 Zr02-Mn0, and CeOt ... 

Steels are homogeneous alloys (solid solutions) made from pig iron. First, pig iron is purified to lower the carbon content and to remove other impurities. Then, appropriate metals are added to form the desired steel. 

Research efforts were subsequently directed at strengthening the Fe-12Ni-0.5A1 alloy. Solid solution strengthening was abandoned early in the investigation, because this approach caused the ductile-brittle transition temperature to increase with a corresponding drop in toughness. 

Concerning miscibility between the metal constituents of an alloy, all types of alloys could be obtained by electrodeposition eutectic-type alloys, solid solution-type alloys, alloys with intermediate phases, and/or intermetallic compounds [1]. According to Krastev and Dobrovolska [40], self-organization phenomena during the electrodeposition of alloys, resulting in pattern and spatiotemporal structure... 

Dental-filling alloy Solid Solution of a liquid (Hg) in a sohd (Ag plus other metals)... 

Gold-silver alloy Solid Solution of two solids (Au + Ag)... 

Figure 19.3 Electroplating. An electrolytic ceU is used to add a coating of a relatively expensive metal to a less expensive base metal. The base metal for the Oscar statues shown here is britta-nium, an alloy (solid solution) of tin, copper, and antimony. They are then sequentially electroplated with copper, nickel, silver, and finally, 24-karat gold. 

ID = GRN string, linear-formula LF string, type TY " type-value (, type-value) ", type-value = a code for one of the classes of coordination compound, mineral, polymer, alloy, solid solution, or diadochous compound, compound with isotopes, or glass or ceramic material. 

Some comments are in order regarding nomenclature First, for metallic alloys, solid solutions are commonly designated by lowercase Greek letters (a, p, y, etc.). With regard to phase boundaries, the line separating the L and a + L phase fields is termed the liq-uidus line, as indicated in Figure 9.3a the hquid phase is present at all temperatures and compositions above this line. The solidus line is located between the a and a + L regions, below which only the solid a phase exists. 

As we have seen, surface segregation in alloys is a fascinating and diverse effect It is not restricted to the surfaces of random alloys (solid solutions) and also occurs in... 

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