Nickel, aluminium alloys containing

The question of the compatibility of metals and alloys with carbon and carbonaceous gases has assumed considerable importance in connection with the development of the gas-cooled nuclear reactor in which graphite is used as a moderator and a constituent of the fuel element, and carbon dioxide as the coolant. Tests of up to 1 000 h on a series of metals and nickel-containing alloys under pressure contact with graphite at 1 010°C" showed that only copper was more resistant than nickel to diffusion of carbon and that the high-nickel alloys were superior to those of lower nickel content. The more complex nickel-chromium alloys containing titanium, niobium and aluminium were better than the basic nickel-chromium materials. 

Valves, with a bellows seal, wholly made of or lined with aluminium, nickel, or alloy containing nickel, either manually or automatically operated and specially designed parts or accessories therefor. 

Vanadium forms alloys with other metals, some of which are of considerable commercial interest. The aluminium alloys containing 10 per cent or less of vanadium are malleable, while those containing 20-25 per cent vanadium may be pulverized in water. The alloy of the composition A1V is the hardest one of the series. A copper-vanadium alloy containing 10-15 per cent vanadium, 60-70 per cent copper, 10-15 per cent aluminium, and 2-3 per cent nickel is prepared and used for the production of solid copper castings and bronzes and in the manufacture of aluminium alloys. Approximately 100 tons of cupro-vana-dium are sold annually to brass and bronze makers.1 Vanadium is also used to harden gold for use in dentistry. 

Jt has recently been stated that iron-aluminium alloys, containing up to about 20 per cent, aluminium and about L per cent, each of nickel and chromium, compare in appearance with high chromium nickel steels, and have been produced in sheet form. Those alloys arc brittle as cast," hut may he made ductile by low-temperature annealing. V idr Journal of Uu Royal Society of Arts, Vol. XC11, No. 4603, p. 240.)... 

Raney nickel is a finely powdered nickel-aluminium alloy that contains hydrogen absorbed onto the surface... 

Thompson and Tracy carried out tests in a moist ammoniacal atmosphere on stressed binary copper alloys containing zinc, phosphorus, arsenic, antimony, silicon, nickel or aluminium. All these elements gave alloys susceptible to stress corrosion. In the case of zinc the breaking time decreased steadily with increase of zinc content, but with most of the other elements there was a minimum in the curve of content of alloying elements against breaking time. In tests carried out at almost 70MN/m these minima occurred with about 0-2% P, 0-2% As, 1% Si, 5% Ni and 1% Al. In most cases cracks were intercrystalline. 

The addition of beryllium and silicon to nickel-palladium alloys gives very good high-temperature brazes, especially for alloys containing aluminium and titanium. 

The discussion so far has been limited to the structure of pure metals, and to the defects which exist in crysteds comprised of atoms of one element only. In fact, of course, pure metals are comparatively rare and all commercial materials contain impurities and, in many cases also, deliberate alloying additions. In the production of commercially pure metals and of alloys, impurities are inevitably introduced into the metal, e.g. manganese, silicon and phosphorus in mild steel, and iron and silicon in aluminium alloys. However, most commercial materials are not even nominally pure metals but are alloys in which deliberate additions of one or more elements have been made, usually to improve some property of the metal examples are the addition of carbon or nickel and chromium to iron to give, respectively, carbon and stainless steels and the addition of copper to aluminium to give a high-strength age-hardenable alloy. 

Heating moist Raney nickel alloy containing 20% aluminium in an autoclave under hydrogen caused the aluminium and water to interact explosively, generating 1 k bar pressure of hydrogen. 

Granular skeletal nickel catalyst with particle size of d = 3-5 mm was prepared by leaching a Ni-Al alloy containing 5D wt% nickel. Half of the amount of aluminium was leached out with 3 wt% NaOH-water solution at 50°C for 12 hours. After leaching the catalyst was washed with distilled water and was kept under an aqueous solution having pH = 9. 

In the case of so-called active soldering an active solder is used a metallic solder containing interface active additives which make certain that the molten solder wets the ceramics. An example of such a solder is a silver / copper alloy with a titanium or titanium / indium additive which can be used when soldering zirconium (IV) oxide to certain steels, aluminium oxide to nickel / cobalt or iron / nickel alloys and aluminium oxide to a iron / nickel / cobalt alloy. 

Steel is an alloy containing chromium, manganese, molybdenum, nickel, vanadium and boron. Copper-nickel alloy, bronze and aluminium alloys are used in making coins. Fusible alloys having low melting points are used as solder and fuses in electrical circuits. 

The intermetallic compound p-NiAl is of great interest for protection of nickel-basc alloys at high temperatures as e. g. in turbine blades. It is applied as a surface alloy layer and protects the base alloy by the formation of an aluminium oxide layer in an oxygen containing atmosphere. This oxide layer grows slowly and is selfhealing. 

Examples of intergranular cracking [7.49] comprise i) carbon steel in caustic, nitrate, acetate and carbonate icarbonate solutions, ii) low-alloy steels in pure water, iii) stainless steels that are liable to ordinary intergranular corrosion in oxygen-containing water, iv) a-brass in ammonia solutions that cause surface films, v) aluminium alloys in water vapour and humid hydrogen gas, vi) P-titanium alloys in metanol solutions, vii) tempered martensitic stainless steels in chloride solutions and viii) nickel alloys in very pure water and alkaline solutions. 

Bronze is essentially an alloy of copper and tin, but may also contain additional elements such as zinc and phosphorus. Bronzes containing copper, tin and phosphorus are known as phosphor bronze, while those containing copper, tin and zinc are known as gunmetal. A wide range of bronzes with additional alloying elements are available for a wide range of applications. These materials include aluminium bronze, nickel aluminium bronze and manganese bronze. 

Alnico A trade name for a series of alloys, containing iron, aluminium, nickel, cob t, and copper, used to make permanent m -nets. 

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