Aluminium tungsten alloys

NANOPOROUS ANODIC OXIDES ON ALUMINIUM - TUNGSTEN ALLOYS... 

Anodization of Al-W alloys with a W concentration in the range of 1-40 at. % has been performed to fabricate a composite nanoporous oxide. An increase of the W content is found to enlarge few times the size of pores. Composite oxide films with the weight ratio WO3/AI2O3 > 50 % have been formed for the first time. Applications of nanostructured aluminium-tungsten oxide composite films are discussed. 

Figure 31 Structure of IBM s solder bumps fabricated at the wafer scale before integrated circuits are connected to wiring boards by the flip chip technology (a) integrated circuit with an area array of solder bumps (b) exploded view showing the bump structure with silicon substrate 1, aluminium bonding pad 2, silicon dioxide 3, silicon nitride passivation 4, titanium-tungsten alloy 5, sputtered copper 6, plated copper 7, and reflowed plated...

Applications Ion implantation is widely employed to improve the life of tools. Thus press tools, dies and gear cutters can be treated to increase their durability by three times or more. Nitrogen-implanted tungsten carbide drawing dies for copper and iron wire can be improved up to fivefold. By implanting chromium, aluminium or silicon a considerable increase in the corrosion resistance of steel can be obtained. Implantation of chromium into aircraft bearing alloys has improved their durability in marine environments . 

Of the 106 or so natural and man-made elements, less than 20% are non-metals. At present, few of the metals are used to any large extent by man, either because of their rarity or their instability. The major "tonnage metals are iron, copper, aluminium, zinc, nickel, and lead. These metals may be alloyed with one another, such as copper and zinc to form brass, and/or may be alloyed with smaller quantities of other metals. Steels are commonly alloyed with chromium, vanadium, molybdenum, or tungsten. Aluminium, for increased lightness and strength, may be alloyed with magnesium. 

Aluminium was determined, with the use of Pyrocatechol Violet, in water and soil [103,104], minerals [33], silica [105], steel and copper alloys [34], molybdenum and tungsten [11]. The FIA technique was applied for determining Al in natural waters [106,107]. 

Copper was determined with cuproine in silicate rocks, biological materials, and sea water [112,113], in environmental samples [113], steel and cast iron [114]. Neocuproine was used for determination of copper in biological materials [12,115], foods [116], sea water [117], beryllium [118], arsenic and gallium [119], tungsten [120], aluminium alloys [117], plutonium [121], tellurium [122], and fertilisers [123]. Bathocuproine was applied in determinations of copper in blood serum [124,125], water [126,127], niobium, tantalum, molybdenum, and tungsten [128], lead and nickel [129], cast iron and steel [66]. 

The dimethylglyoxime method has been used for determination of Ni in foodstuffs [10], platinum-group metals [69], iron ores [70], niobium, tantalum, molybdenum, and tungsten [71], steel [72], sewage [73], and aluminium alloys [74]. Dimethylglyoxime in the presence of oxidant was used for determining Ni in foodstuff [75], sea-water [76], plants [77], steel [5], lead and antimony [78], copper alloys [79], zinc and cadmium [80], and tungsten and its... 

The method involving the Mo-V-P acid has been used in determinations of phosphorus in biological tissues [127], plant material [128], fruits [129], fish products [130], foodstuffs [131], phosphate minerals [132], cast iron and steel [133,134], niobium, zirconium and its alloys, titanium and tungsten, aluminium, copper, and white metal [135], nickel alloys [134,135], metallurgy products [136], molybdenum concentrates [137], silicon tetrachloride [7], cement [138], and lubricants[139]. The flow injection technique has been applied for determining phosphate in minerals [140] and in plant materials [141]. 

The method based on the use of DAM has been applied for determining titanium in biological materials [11], silicate rocks [32,99,100], cast iron and steel 33], molybdenum and tungsten [6,18], vanadium [18], zirconium, hafnium, and niobium [101], lithium fluoride [102], nickel, aluminium, and molybdenum alloys [11], and ferrotitanium [103]. Titanium was determined in aluminium alloys with the use of DAM in the presence of SnCh [35,104]. 

The complex of Ga with Semiethylthymol Blue was used to determine Ga in minerals and ores [1]. Gallium in aluminium alloy was determined in the form of tungsten-molybdenum complexes [2]. 

Tungsten has a marked effect on the properties of alloys, consequently a great variety of alloys have been prepared. The usual effect of tungsten is to produce hardness and greater resistance to oxidation and corrosion. Some tunpten alloys are said6 to be actually harder than diamonds. Aluminium hardened with a small per cent of tungsten, called " partinium, 7... 

The new nanostructure porous material based on anodic A12O3 and WO3 has been fabricated. The pore sizes can be tuned both by anodic forming regimes and W atom content in initial Al-W alloy films. The composite nanostructures based on anodic aluminium and tungsten oxides opens new opportunities for nanotechnology in electronics and photonics. 

Alloys are metallic substances containing two or more elements which are miscible when molten and do not separate when solidified. They may be liquid or solid. This mixture of elements, usually but not necessarily metals, allows careful manipulation of strength, melting point, corrosion resistance, magnetic, thermal, electrical, and other properties steel, for example, is an alloy of iron and carbon often present with nickel, chromium, copper, aluminium, boron, tungsten, manganese, cobalt, silicon, and other elements. 

A synthetic or man-made diamond material is now available which is extremely tough with a hardness approaching that of natural diamond. A layer of this synthetic diamond material is bonded to a tough shock-resisting base of cemented carbide for use in the form of tips. The range of application is on non-ferrous metals such as aluminium alloys, magnesium alloys, copper, brass, bronze and zinc alloys and non-metallic materials such as ceramics, porcelain and plastics. This material will also machine fully sintered tungsten carbide. 

Although not an ore, ferroniobium is produced by a smelting operation from columbite, in reasonably large quantities and at a cost which is sufficiently attractive for it to be used as a source material for the produc-ton of pure niobium. It consists essentially of an alloy of about 60 per cent niobium, 9 per cent tantalum and 24 per cent iron with smaller amounts of tungsten, titanium, manganese and aluminium, etc. Processes have been based upon dissolution of ferroniobium in acids (e.g. a mixture of sulphuric and hydrofluoric acids) or fusion with potassium carbonate, but the most satisfactory method is to dissolve the alloy in a concentrated potassium hydroxide solution. 

The tantalum carbides and silicides and tungsten carbides cited above are used for their hardness, corrosion resistance in hot environment and their semiconducting properties, while niobium alloys (niobium-germanium, niobium-aluminium...) receive much attention for their properties of superconductivity. 

All these experiences were rather short-lived, because these vessels suffered very soon (after a few months) from severe corrosion the alloy of the plates contained 6% copper In order to obtain acceptable mechanical strength, copper had been added to the primary aluminium in a concentration between 6 and 10% (some producers proposed adding 2-3% nickel, and even tungsten). 

---