Molybdenum-tantalum alloys

Tantalum and 2kconium exhibit the highest corrosion resistance to HCl. However, the corrosion resistance of 2ironium is severely impaHed by the presence of ferric or cupric chlorides. Tantalum—molybdenum alloys containing more than 50% tantalum are reported to have exceUent corrosion resistance (see Molybdenumand molybdenum alloys) (69). Pure molybdenum and tungsten are corrosion resistant in hydrochloric acid at room temperature and also in 10% acid at 100°C but not in boiling 20% acid. 

Tantalum-Molybdenum Schumb, Radtke and Bever studied the corrosion resistance of tantalum-molybdenum alloys that form a continuous series of solid solutions. The results of tests of up to 500 hours duration (Table 5.26) indicate the corrosion resistance of the alloy to be substantially that of tantalum, provided its concentration exceeds 50%. 

Table 5.26 The corrosion behaviour of tantalum-molybdenum alloys in concentrated sulphuric and hydrochloric acids at 55°C solutions saturated with oxygen...

Hydrogen chloride gas may be stored in steel cyhnders free of contaminants. Monel, pure nickel, or its aUoy, inconel, may also be used for storage and transportation up to 500°C. Hydrochloric acid may be stored in glass bottles or in containers made up of tantalum or tantalum-molybdenum alloys, or other alloys of zirconium, molybdenum, and tungsten. 

Corrosion Rates of Tantalum-Molybdenum Alloys in Concentrated Sulfuric and Hydrochloric Acids at 150°C... 

Nitrogen and carbon are the most potent solutes to obtain high strength in refractory metals (55). Particulady effective ate carbides and carbonitrides of hafnium in tungsten, niobium, and tantalum alloys, and carbides of titanium and zirconium in molybdenum alloys. 

TLC atomic emission spectrometric (AES) method was developed to determine tantalum in molybdenum alloys containing > 0.5% tantalum. The procedure involves the separation of tantalum from molybdenum alloy on a silica gel layer (0.3 mm thick) using 10.0-MHCl -f acetone (1 1) as developer and the subsequent determination of tantalum by AES [43]. 

Promisel, N. E. (1964). Tungsten, Tantalum, Molybdenum, Niobium and their alloys. Pergamon Press, New York, page 293. 

Molybdenum alloys with tantalum in all proportions. Alloys containing from 10 to 40 per cent, tantalum have been suggested for the construction of chemical and electrical apparatus.3 When the molybdenum content is less than 5 per cent., the product can be drawn into wire 0 1 mm. diameter. 

A ZnS insulating layer 114 is deposited on a sensing layer 112 of HgCdTe. A refractory metal, such as tantalum, molybdenum, tungsten, titanium or refractory metal alloys such as titanium/tungsten, is sputter-deposited onto the insulating layer. The structure is connected to... 

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... 

Because of its combination of chromium, molybdenum, carbon, and niobium-H tantalum, the alloy retains its strength and oxidation resistance at elevated temperatures. 

Corrosion resistance was studied on a series of tantalum-molybdenum solid solution alloys. The results of corrosion tests run for 500 h in both concentrated sulfuric and hydrochloric acids are shown in Table 21.8. Although the corrosive attack was small for all cases, as long as the alloy contained at least 50 at% tantalum, the corrosion resistance of tantalum was retained. 

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