| 摘要 |
<p>Niobium alloys containing silicon in amount at least equivalent to that required to form the silicide CB2Si are freed from tin by treatment with a solvent for tin, which may be sulphur chloride or hot caustic alkali, but is preferably an acid such as hydrochloric acid. Alloys containing too little silicon may be alloyed directly with silicon to render them amenable to treatment, or the required silicon content may be obtained by reduction of silica with a stanniferous niobium oxide ore.ALSO:Niobium alloys containing silicon in excess of a ratio of one part of silicon to six and a half parts of niobium are wholly or partially freed from tin by treating them, preferably in a comminuted condition, with a solvent for tin, which may be sulphur chloride or hot caustic alkali, but is preferably an acid such as hydrochloric acid. The minimum silicon-niobium ratio corresponds to that present in niobium-silicide Nb2Si, and tin may be removed from alloys originally containing less silicon by increasing their content of silicon prior to treatment with acid. The alloys for treatment may be obtained by with smelting stanniferous niobium oxide ores a reducing agent such as carbon, aluminium, or silicon, and the required silicon content may be obtained by reduction of silicon with the ore or by alloying a niobium alloy with silicon. In examples, the alloys treated contain, in addition to niobium, tin, and silicon, mainly iron and tantalum.</p> |
