Copper solid solution

Class I highest degree of homogeneity silver-copper solid solution. Objects typical of this structure are the Oval Bowl, King Torso, and the Vicarello Goblet. 

By drawing a staircase in Figure 6.17, determine what composition will result from three successive zone refining passes starting with a gold-copper solid solution of gold mole fraction equal to 0.70. What would many successive zone refining passes lead to if the curves had a maximum instead of a minimum ... 

NH2CONH2 = NH2CONHCONH2 + NH3 Dissolve the solid residue in a few ml. of warm 10% NaOH solution, cool and add i drop of very dilute copper sulphate solution. A purple coloration is obtained. ... 

The difference in stability between FeO and NiO is not as large as that between iron and copper oxides, and so the preferential oxidation of iron is not so marked in pentlandite. Furthermore, the nickel and iron monoxides form a continuous series of solid solutions, and so a small amount of nickel is always removed into die oxide phase (Table 9.2). 

As you can see from the tables in Chapter 1, few metals are used in their pure state -they nearly always have other elements added to them which turn them into alloys and give them better mechanical properties. The alloying elements will always dissolve in the basic metal to form solid solutions, although the solubility can vary between <0.01% and 100% depending on the combinations of elements we choose. As examples, the iron in a carbon steel can only dissolve 0.007% carbon at room temperature the copper in brass can dissolve more than 30% zinc and the copper-nickel system - the basis of the monels and the cupronickels - has complete solid solubility. 

The alloy aluminium-4 wt% copper forms the basis of the 2000 series (Duralumin, or Dural for short). It melts at about 650°C. At 500°C, solid A1 dissolves as much as 4 wt% of Cu completely. At 20°C its equilibrium solubility is only 0.1 wt% Cu. If the material is slowly cooled from 500°C to 20°C, 4 wt% - 0.1 wt% = 3.9 wt% copper separates out from the aluminium as large lumps of a new phase not pure copper, but of the compound CuAlj. If, instead, the material is quenched (cooled very rapidly, often by dropping it into cold water) from 500°C to 20°C, there is not time for the dissolved copper atoms to move together, by diffusion, to form CuAlj, and the alloy remains a solid solution. 

Single-phase solid solution of copper in aluminium... 

But in metals it is relatively common for solid solutions to form. The atoms of one element may enter the crystal of another element if their atoms are of similar size. Gold and copper form such solid solutions. The gold atoms can replace copper atoms in the copper crystal and, in the same way, copper atoms can replace gold atoms in the gold crystal. Such solid solutions are called alloys. Some solid metals dissolve hydrogen or carbon atoms—steel is iron containing a small amount of dissolved carbon. 

On the other hand, upon closer examination even the copper-gold solid solutions evince serious discrepancies with the quasichemical theory. There is a composition range where the entropy of solution is larger than that for random mixing (see Fig. 1) where... 

Copper-gold, solid solution (CuAu8), 129 system, 123... 

Gold-copper, alloy (Au5Cu5, AuBCuB(S)), calculation of thermodynamic quantities, 136, 142 solid solution (CuAu), 129 Gold-lead, alloy (Au5Pb5), calculation of thermodynamic quantities, 136 Gold-nickel, alloy (Au5Ni8), calculation of thermodynamic quantities, 136, 142... 

Copper preferentially occupies the holes in /3-rh boron as shown by powder diffraction . In the CuB solid solution the D hole is represented by two crystallographic positions (denoted 2 and 2" in Fig. 1) " situated 40 pm from each other. The accommodation of the Cu atoms in three (or four) different holes in the preferred order shown in Fig 1 demonstrates the complex nature of the solid solution. 

One way that a solid metal can accommodate another is by substitution. For example, sterling silver is a solid solution containing 92.5% silver and 7.5% copper. Copper and silver occupy the same column of the periodic table, so they share many properties, but copper atoms (radius of 128 pm) are smaller than silver atoms (radius of 144 pm). Consequently, copper atoms can readily replace silver atoms in the solid crystalline state, as shown schematically in Figure 12-4. 

Metal alloys are solid solutions that can be either substitutional (copper in silver) or interstitial (carbon in iron). 

Walshe, J.L. and Solomon. M. (1981) An investigation into the environment of formation of the volcanic-hosted Mt. Lyell copper deposits using geology, mineralogy, stable isotopes and a six-component chlorite solid solution model. Econ. Geol, 76, 246-284. 

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