Alloys containing sodium

Sodium does not form alloys with aluminum but is used to modify the grain stmcture of aluminum—silicon alloys and aluminum—copper alloys for improved machinabiUty. Sodium—gold alloy is photoelectricaHy sensitive and may be used ia photoelectric cells. A sodium—2iac alloy, containing 2 wt % sodium and 98 wt % 2iac, is used to deoxidi2e other metals. 

Nickel-iron alloys are more resistant than iron to attack by solutions of various salts. In alternate immersion tests in 5% sodium chloride solution Fink and De Croly determined values of 2-8, 0-25 and 0-5 g m d for alloys containing 37, 80 and 100% nickel compared with 46 g m d for iron. Corrosion rates of about 0.4 g m d are reported by Hatfield for Fe-30Ni alloy exposed to solutions containing respectively 5 Vo magnesium sulphate, 10 Vo magnesium chloride and 10% sodium sulphate the same alloy corroded at a rate of about 1.2 g m d in 5% ammonium chloride. 

In a similar determination described by Lingane and Jones,11 an alloy containing copper, bismuth, lead, and tin is dissolved in hydrochloric acid as described above, and then 100 mL of sodium tartrate solution (0.1 M) is added, followed by sufficient sodium hydroxide solution (5M) to adjust the pH to 5.0. After the addition of hydrazinium chloride (4 g), the solution is warmed to 70 °C and then electrolysed. Copper is deposited at —0.3 volt, and then sequentially, bismuth at —0.4 volt, and lead at —0.6 volt all cathode potentials quoted are vs the S.C.E. After deposition of the lead, the solution is acidified with hydrochloric acid and the tin then deposited at a cathode potential of — 0.65 volt vs the S.C.E. 

Ammonium nitrate containing the sulfate readily explodes on contact with potassium or its alloy with sodium. 

The ions having five tin or lead atoms are prepared by the reaction of a solution containing sodium and the cryptand reacting with alloys of sodium and tin or lead, respectively. It should also be mentioned that numerous derivatives of these materials have been prepared that contain alkyl and other groups. 

Several reductions have been achieved by dissolving a nickel-aluminum alloy containing usually 50% of aluminum in 20-50% aqueous sodium hydroxide in the presence of a reducible compound. Since under such conditions elemental hydrogen is generated by dissolution of aluminum, and since Raney nickel is formed in this process, such reductions have to be considered catalytic hydrogenations rather than dissolving metal reductions. Their outcome certainly points to the former type. 

Among the metallic reducing systems [42a, b] which have been suggested are magnesium with anhydrous methanol [42a], and an alloy of sodium and lead (sold as Drynap ) in ethanol [43, 44], In the case of the magnesium-methanol reduction, the product mixture usually contains azoxy-, azo-, hydrazo-, amino-, and hydroxylamine products, although approximately 75% of the product consists of a mixture of azoxy and azo compounds. The Dry-nap reduction also seems to lead frequently to mixtures of azoxy and azo compounds. 

Metal Coatings. Tellurium chlorides, as well as tellurium dioxide in hydrochloric acid solution, impart permanent and attractive black antique finish to silverware, aluminum, and brass. Anodized aluminum is colored dark gold by tellurium electro deposition. A solution containing sodium tellurate and copper ions forms a black or blue-black coating on ferrous and nonferrous metals and alloys. Addition of sodium tellurite improves the corrosion resistance of electroplated nickel. Tellurium diethyldithiocarbamate is an additive in bright copper electroplating (see Electroplating). 

A few of the relations of the alkali metals with one another have been investigated. Potassium with about 30 per cent, of sodium forms an alloy which is liquid at ordinary temp., and which has the appearance of mercury. This becomes pasty at 8°, and solidifies at a lower temp. If the alloy contains 77 per " /o" S>"x cent, of potassium, it remains liquid even... 

Copper.—Alloys of copper and vanadium are prepared by firing a mixture of vanadium pentoxide, copper oxide, aluminium shot, lime, soda-ash, and fluorspar with the aid of sodium peroxide in a magnesia-lined crucible.2 Electrolytic methods have also been employed, and are applicable for the preparation of other vanadium alloys.3 An alloy containing 3-38 per cent, of vanadium and 96-52 per cent, of copper was found to be harder than copper and could be drawn into wire. An aluminium-copper-vanadium alloy has been prepared.4... 

Caution. The residues on the glassware and the frit may contain sodium-potassium alloy and/or tris(trimethylsilyl)arsine and should not be exposed to air until disposal. tert-Butyl alcohol and isopropyl alcohol can be used to destroy these pyrophoric compounds however, this should be performed in a fume hood, as arsine gas may be generated. The solid on the frit can be mixed with class D metal fire extinguisher and subsequently treated with either of the aforementioned alcohols. 

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