ALUMINIUM AND ITS ALLOYS

Pure aluminium lacks mechanical strength but has higher resistance to corrosion than its alloys. The main structural alloys used are the Duralumin (Dural) range of aluminium-copper 

One of the most important characteristics of aluminium and its alloys is the thin oxide film which forms on their surfaces when exposed to the atmosphere. If the oxide film is broken it will reform quickly, and this gives these materials excellent corrosion-resistance. This oxide film can be artificially thickened to give added protection - a process known as anodising - and can be easily coloured to provide a highly decorative appearance. 

Aluminium and its alloys are available in a wide range of shapes and forms. 

Both sheet and strip are available with the surface prepainted in a 

The uses of aluminium and its alloys are virtually limitless, covering the fields of transport electrical, structural, civil and general engineering household items packaging in the chemical and food industries and many more. 

Applications in transport include cladding and floor sections of commercial vehicles, prepainted sheet for caravans, the superstructure of ships and hovercraft and a variety of components in aircraft. 

Both sheet and strip are available with the surface prepainted in a range of colours, used in the manufacture of caravans. 

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Metals and alloys Iron and steels Aluminium and its alloys Copper and its alloys Nickel and its alloys Titanium and its alloys... 

Immersed aluminium and its alloys have excellent resistance to attack by distilled or pure condensate water, and are used in industry in condensing equipment and in containers for both distilled and deionised water, as well as in steam-heating systems... 

The Properties of Aluminium and its Alloys, 6th edn. The Aluminium Federation, Birmingham (1968)... 

CP30I2 1972, Cleaning and preparation of metal surfaces , B.S.I., London Wernick, S. and Pinner, R., The Surface Treatment and Finishing of Aluminium and Its Alloys, Robert Draper, London, 3rd edn (1964)... 

Electroplating aluminium and its alloys requires a similar technique. In aqueous solutions it is impossible to lower the potential sufficiently to reduce an alumina film, so the substrate is immersed in a strongly alkaline solution capable of dissolving it ... 

Heat treatment after plating Heat treatment may be necessary after plating to improve the adhesion of coatings on aluminium and its alloys when certain processes, e.g. the Vogt process, are used, or to minimise hydrogen embrittlement of steel parts. Care is needed since heating may distort the part and impair the mechanical properties of the substrate. 

Heat treatment to improve adhesion on aluminium and its alloys is normally carried out at 120-140°C for 1 h. 

Oil-base (including oil-modified alkyd resin) paint films should not be used in alkaline environments as the paint will deteriorate owing to saponification alkali-resistant coatings are provided by some cellulose ethers, e.g. ethyl cellulose, certain polyurethane, chlorinated rubber, epoxy, p.v.c./ p.v.a. copolymer, or acrylic-resin-based paints. In particular, aluminium and its alloys should be protected by alkali-resistant coatings owing to the detrimental effects of alkali on these metals. 

Aluminium and its alloys (a) Alkaline dip Alkaline chromate Oxide/hydroxide with perhaps some chromate... 

Method of specifying anodic oxidation coatings on aluminium and its alloys Specification for electroplated coatings of tin... 

Methyl bromide C F T Most common metals when Copper, tin, zinc and their alloys. Avoid mercury Aluminium and its alloys... 

V. F. Henley, Anodic oxidation of Aluminium and its Alloys. Pergamon Press, Oxford (1982). 

Metal powders or fibres ignite in an oxygen-fed resonance tube [1], There have been fires in aluminium pressure regulators for oxygen. Aluminium and its alloys can become flammable at as low a pressure as 2 bar. Aluminium regulators are being replaced by brass, use of aluminium cylinders is still regarded as safe [2]. 

When constructing electrolyzers for this process it is rather difficult to find suitable materials which can resist the effects of fluorine as it attacks most metals even at normal temperature fortunately continuous fluoride coatings are formed on the surface of some metals which protects them against further corrosion at least to a certain extent. Such metals are iron, nickel, Monel metal, aluminium and its alloys, magnesium and especially electron one of its alloys. However, the protective films are only stable at lower temperatures. At elevated temperatures a violent reaction proceeds between the fluorine and the metal. Monel metal and copper have relatively the best resistance against fluorine at elevated temperatures. These metals, therefore, were widely used to construct electrolyzers. In more recent designs, copper was replaced by steel or electron. 

Among other organic reagents, Ga has been determined with Chrome Azurol S in aluminium, aluminium chloride, and peat bath [62], with Xylenol Orange in biological samples [63], with PAR in aluminium and its alloys [64], with haematoxylin in aluminium alloys [55], with Carminic Acid in gallium arsenide semiconductor materials [65], and with Semimethylthymol Blue in minerals and ores [66]. 

The PAR method has been used for determination of indium in environmental samples [66], aluminium and its alloys [67], and in nickel and zinc alloys [26]. 

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