Aluminium-copper-magnesium alloys

Contact of brass, bronze, copper or the more resistant stainless steels with the 13% Cr steels in sea-water can lead to accelerated corrosion of the latter. Galvanic contact effects on metals coupled to the austenitic types are only slight with brass, bronze and copper, but with cadmium, zinc, aluminium and magnesium alloys, insulation or protective measures are necessary to avoid serious attack on the non-ferrous material. Mild steel and the 13% chromium types are also liable to accelerated attack from contact with the chromium-nickel grades. The austenitic materials do not themselves suffer anodic attack in sea-water from contact with any of the usual materials of construction. 

Both metals are applied to copper-base alloys, stainless steels and titanium to stop bimetallic corrosion at contacts between these metals and aluminium and magnesium alloys, and their application to non-stainless steel can serve this purpose as well as protecting the steel. In spite of their different potentials, zinc and cadmium appear to be equally effective for this purpose, even for contacts with magnesium alloys Choice between the two metals will therefore be made on the other grounds previously discussed. 

Emission spectroscopy has been employed for the analysis of various alloys, namely aluminium, copper, magnesium, zinc, lead, and tin. 

Individually indexed alloys or intermetallic compounds are Aluminium amalgam, 0051 Aluminium-copper-zinc alloy, 0050 Aluminium-lanthanum-nickel alloy, 0080 Aluminium-lithium alloy, 0052 Aluminium-magnesium alloy, 0053 Aluminium-nickel alloys, 0055 Aluminium-titanium alloys, 0056 Copper-zinc alloys, 4268 Ferromanganese, 4389 Ferrotitanium, 4391 Lanthanum-nickel alloy, 4678 Lead-tin alloys, 4883 Lead-zirconium alloys, 4884 Lithium-magnesium alloy, 4681 Lithium-tin alloys, 4682 Plutonium bismuthide, 0231 Potassium antimonide, 4673 Potassium-sodium alloy, 4646 Silicon-zirconium alloys, 4910... 

The cuprizone method was used for determining copper in plant materials [130], biological samples [12], lead and its alloys [131], aluminium and magnesium alloys [132], platinum alloys [133], cadmium sulphide [134], borate glass [135], and petroleum samples [136]. 

Tests have been carried out on light alloys, aluminium-copper-magnesium, having the average composition already given and corresponding with the light alloy known as duralumin ... 

Hudson reported lives of about 4y years for 38 /tm thick metal-sprayed aluminium coatings on steel exposed at Sheffield, and more than 1 ly years for coatings 75/tm thick. Sprayed aluminium coatings (approximately 125/tm thick) have also provided complete protection against exfoliation and stress corrosion to aluminium-copper-magnesium (HE 15) and aluminium-zinc-magnesium (DTD 683) alloys in tests lasting up to 10 years in industrial and marine environments . 

Three broad classes of aluminium alloys will be considered here the heat-treatable high-strength aluminium-copper 2000 series and aluminium-zinc-magnesium 7000 series alloys and the non-heat-treatable lower strength aluminium-magnesium 5000 series alloys which are used extensively in marine applications. 

Silver, brass, aluminium, steel, copper, nickel can cause decomposition at elevated temperatures. Magnesium alloys and aluminium containing >2% magnesium. Natural rubber... 

Almond shell Aluminium, atomized Aluminium, flake Aluminium-cobalt alloy Aluminium-copper alloy Aluminium-iron alloy Aluminium-lithium alloy Aluminium—magnesium alloy Aluminium-nickel alloy Aluminium-silicon alloy Aluminium acetate... 

Lead—tin alloys, 4877 Lead—zirconium alloys, 4878 Lithium—magnesium alloy, 4676 Lithium—tin alloys, 4677 Plutonium bismuthide, 0231 Potassium antimonide, 4668 Potassium—sodium alloy, 4641 Silicon—zirconium alloys, 4904 Silver—aluminium alloy, 0002 Silvered copper, 0003 Sodium germanide, 4412 Sodium—antimony alloy, 4791 Sodium—zinc alloy, 4792 Titanium—zirconium alloys, 4915... 

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. 

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