Niobium and niobium alloy tubes

The main strengthening ways of niobium are solution, precipitation and deformation heat treatment. In niobium alloy, the alloy elements tungsten and molybdenum can significantly improve the high and low temperature strength, but too much content will reduce the alloy process performance. Tantalum is a moderately strengthening element and can reduce the plastic-brittle transition temperature of alloys. Another way to strengthen niobium alloy is to add titanium, zirconium and hafnium as well as a certain proportion of carbon to form a dispersed carbide phase for precipitation strengthening. In addition, these active elements can improve other properties, such as titanium can obviously improve the alloy oxidation resistance and process properties; Hafnium and zirconium can improve the corrosion resistance of molten alkali metals. Hafnium can significantly improve the oxidation resistance and weldability of the alloy. High strength niobium alloys generally contain a large number of solid solution elements (tungsten, molybdenum, tantalum, etc.) for solution strengthening, while precipitation strengthening is also used to give the alloys high strength (see metal strengthening). The plastic processing of these alloys is difficult and the deformation parameters need to be strictly controlled. In addition to Nb-10W-1Zr-0.1c alloy which contains carbide precipitation strengthening phase, other alloys have medium content of solid solution strengthening element to ensure excellent comprehensive properties. As long as appropriate amount of titanium, zirconium and hafnium are added to low strength alloys, excellent machining performance can be guaranteed.

The metal niobium can be prepared by point melting of potassium sepharoflonobate, also can be made by metal sodium sepharoflonobate potassium or metal aluminum reduction of niobium pentaoxide. Pure niobium is used to remove residual gas in the electron tube, and niobium doping in steel can improve the oxidation resistance of steel at high temperature and improve the welding performance of steel. Niobium is also used to make high temperature cermets.

Niobium and niobium alloy tubes, rods and wires are widely used in chemical, electronic, aerospace and other fields due to their high melting point, corrosion resistance and good cold working performance. Niobium and niobium alloy rods are used as structural materials for aero-engines and rocket nozzles, reactor internal components and cladding materials, and can only be used to make corrosion-resistant parts that are resistant to nitric acid, hydrochloric acid or sulfuric acid corrosion conditions. Adding zirconium into niobium can obviously improve the oxidation resistance and strength of the material. Niobium and zirconium alloy wire are widely used in the manufacture of high pressure sodium lamp and anode lead of electrolytic capacitor.