Tantalum and its alloy blank can be produced by powder metallurgy process or melting process. Powder metallurgy process is mainly used to produce small tantalum products and blanks for processing. The powder tantalum material is prepared by thermal reduction or electrolysis, and then pressed into shape and sintered under vacuum. The sintering process depends on the use requirements of the product. Primary sintering (1600 ~ 2200℃) is used to produce electrodes and porous anodes for smelting. Secondary sintering is used to produce billets for forging, rolling, drawing and other plastic processes. Forging or rolling is often carried out between two sintering, and the processing rate is about 50%. Secondary sintering temperature is 2000 ~ 2700℃.
Vacuum consumable arc and electron beam melting is a common method to produce tantalum and its alloy ingots. Electron beam melting process is mainly used for tantalum purification, consumable arc melting process can produce large diameter and more uniform alloy composition of ingot, consumable arc melting electrode can be made of sintered rod or electron beam melting ingot, the ingot obtained by melting is coarse grain, often need to be broken as cast grain to improve the plasticity. Electron beam region melting can be used to further purify tantalum or prepare single crystals.
Tantalum can be used to make various malleable alloys with high melting points. These alloys are used as materials for superhard metalworking tools and to make superalloys for jet engines, chemical laboratories, nuclear reactors and missiles. Tantalum is highly malleable and can be stretched into silk. These tantalum wires are used to vaporize various metals, such as aluminum. Tantalum is widely used to make surgical tools and implants because it protects against biological fluids and does not irritate tissue. Tantalum, for example, bonds directly to hard tissue, so many bone implants have porous tantalum coatings.
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Tantalum resists almost all acids except hydrofluoric acid and hot sulfuric acid. Tantalum can therefore be used as a vessel for chemical reactions and as a conduit for corrosive liquids. The heat exchange coils used in the hydrochloric acid heating process are tantalum. Tantalum is used in large quantities in the production of electron tubes for UHF radio transmitters. Tantalum traps the oxygen and nitrogen in the tubes to form oxides and nitrous compounds, respectively, thus maintaining the desired high vacuum.
