Pure copper

To convert to cal, divide by 4.184. To convert mPa to )J.m Hg, divide by 133.3. lACS = International Annealed Copper Standard. Pure copper Table 2. Corrosion of Niobium Metal = 100%. ... 

Direct Process. Passing methyl chloride through a fluidized bed of copper and siUcon yields a mixture of chlorosilanes. The rate of methylchlorosilane (MCS) production and chemical selectivity, as determined by the ratio of dimethydichlorosilane to the other compounds formed, are significantly affected by trace elements in the catalyst bed very pure copper and siUcon gives poor yield and selectivity (22). 

A 99.5% Cu—0.5% Te alloy has been on the market for many years (78). The most widely used is alloy No. CA145 (number given by Copper Development Association, New York), nominally containing 0.5% tellurium and 0.008% phosphorous. The electrical conductivity of this alloy, in the aimealed state, is 90—98%, and the thermal conductivity 91.5—94.5% that of the tough-pitch grade of copper. The machinahility rating, 80—90, compares with 100 for free-cutting brass and 20 for pure copper. 

Table 4. Properties of Pure Copper, Silver, and Gold ...

Figure 1 also shows the decrease in tensile elongation (a common measure of ductiUty) that accompanies the strength increase with cold working. Whereas these particular rolling curves include up to 70% reduction in thickness, pure copper is capable of being roUed much further without fracturing. 

Electrical—Thermal Conductivities. Electrical conductivities of alloys (Table 5) are often expressed as a percentage relative to an International Annealed Copper Standard (lACS), ie, units of % lACS, where the value of 100 % lACS is assigned to pure copper having a measured resistivity value of 0.017241 Q mm /m. The measurement of resistivity and its conversion to % lACS is covered under ASTM B193 (8). 

Electrical conductivity of copper is affected by temperature, alloy additions and impurities, and cold work (9—12). Relative to temperature, the electrical conductivity of armealed copper falls from 100 % lACS at room temperature to 65 % lACS at 150°C. Alloying invariably decreases conductivity. Cold work also decreases electrical conductivity as more and more dislocation and microstmctural defects are incorporated into the armealed grains. These defects interfere with the passage of conduction electrons. Conductivity decreases by about 3—5% lACS for pure copper when cold worked 75% reduction in area. The conductivity of alloys is also affected to about the same degree by cold work. 

To a good approximation, thermal conductivity at room temperature is linearly related to electrical conductivity through the Wiedemann-Eran2 rule. This relationship is dependent on temperature, however, because the temperature variations of the thermal and the electrical conductivities are not the same. At temperatures above room temperature, thermal conductivity of pure copper decreases more slowly than does electrical conductivity. Eor many copper alloys the thermal conductivity increases, whereas electrical conductivity decreases with temperature above ambient. The relationship at room temperature between thermal and electrical conductivity for moderate to high conductivity alloys is illustrated in Eigure 5. 

Copper. The physical properties of pure copper are given in Table 11. The mechanical properties of pure copper are essentially the same as those for ClOl and CllO. The coppers represent a series of alloys ranging from the commercially pure copper, ClOl, to the dispersion hardened alloy C157. The difference within this series is the specification of small additions of phosphoms, arsenic, cadmium, tellurium, sulfur, zirconium, as well as oxygen. To be classified as one of the coppers, the alloy must contain at least 99.3% copper. 

Determination. The most accurate (68) method for the deterrnination of copper in its compounds is by electrogravimetry from a sulfuric and nitric acid solution (45). Pure copper compounds can be readily titrated using ethylene diamine tetracetic acid (EDTA) to a SNAZOXS or Murexide endpoint. lodometric titration using sodium thiosulfate to a starch—iodide endpoint is one of the most common methods used industrially. This latter titration is quicker than electrolysis, almost as accurate, and much more tolerant of impurities than is the titration with EDTA. Gravimetry as the thiocyanate has also been used (68). 

Copper-plating bath compositions of various types have been used. A typical bath formulation consists of 200 g copper sulfate crystals, 30 mL cone, sulfuric acid, 2 mL phenylsulfonic acid, and 1000 mL distUled water. A pure copper anode may be used a copper anode containing a trace of phosphoms reduces sludge accumulation in the plating bath. 

The complexers maybe tartrate, ethylenediaminetetraacetic acid (EDTA), tetrakis(2-hydroxypropyl)ethylenediamine, nittilotriacetic acid (NTA), or some other strong chelate. Numerous proprietary stabilizers, eg, sulfur compounds, nitrogen heterocycles, and cyanides (qv) are used (2,44). These formulated baths differ ia deposition rate, ease of waste treatment, stabiHty, bath life, copper color and ductiHty, operating temperature, and component concentration. Most have been developed for specific processes all deposit nearly pure copper metal. 

Aluminum and Alloys Aluminum and its alloys are made in practically all the forms in which metals are produced, including castings. Thermal conductivity of aluminum is 60 percent of that of pure copper, and unalloyed aluminum is used in many heat-transfer applications. Its high electrical conductivity makes aluminum popular in electrical apphcations. Aluminum is one of the most workable of metals, and it is usually joined by inert-gas-shielded arc-welding techniques. 

Let us first of all look at what happens when we load a cracked piece of a ductile metal - in other words, a metal that can flow readily to give large plastic deformations (like pure copper or mild steel at, or above, room temperature). If we load the material sufficiently, we can get fracture to take place starting from the crack. If you examine the... 

Estimate the percentage volume contraction due to solidification in pure copper. Use the following data = 1083°C density of solid copper at 20°C = 8.96 Mg m ... 

You heat pure copper. At 1083°C it starts to melt. While it is melting, solid and liquid... 

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. 

The major part of this blister copper is further purified electro lytic ally by casting into anodes which are suspended in acidified CUSO4 solution along with cathodes of purified copper sheet. As electrolysis proceeds the pure copper is deposited on the cathodes while impurities collect below the anodes as anode slime which is a valuable source of Ag, Au and other precious metals. 

On tlie basis of tills inforniation, tediniques for tlie s7iitliesis of pure copper compoimds were devdoped. Hie following parameters played an imporianL role ... 

LEED, namely one with a, c(2x2) and one with a, p(2x2) superstructure. They are compatible with CusPt and CusPta layers. The first atomic layer was in both cases found by means of photoemission of adsorbed xenon to be pure copper. Details of the experimental work can be found in ref. 9 and 10. A schematic view of both structures can be seen in figure 1. Both consist of alternating layers of pure copper and of mixed composition. In the CuaPt case, the second and all other evenly numbered layers have equal numbers of copper and platinum atoms, whereas in the CusPta case the evenly numbered layers consist of thrice as many platinum as copper atoms. 

The next step was then to simulate, a four layer CuaPt overlayer on the (100) surface of the platinum substrate. The first layer w as taken to he pure copper, as was found in the experiment, while the second was a mixed copper-platinum, the third a copper and the fourth again a mixed layer. The fifth and all other layers were pure platinum. For the alloy overlayer the same potentials as for the CuaPt single crystal w ere used, and the potential of pure platinum for the substrate. 

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