What are 8 Uses for Tantalum?

Niobium vs. Tantalum

Due to their similar properties as functional and structural materials, niobium and tantalum have common areas of application or in most cases can be substituted for each other. In practice, however, the main areas of application and usage vary considerably due to differences in resources and properties. Niobium is abundant and is produced and consumed in large quantities; tantalum is less abundant and is produced and consumed in small quantities.

ta powder

Chemical properties of tantalum

Tantalum has excellent chemical properties and is extremely resistant to corrosion, not reacting to hydrochloric acid, concentrated nitric acid, or “aqua regia”, both under cold and hot conditions. However, tantalum can be corroded in hot concentrated sulfuric acid. Below 150°C, tantalum will not be corroded by concentrated sulfuric acid, but will only react above this temperature.

In 175 degrees in concentrated sulfuric acid for 1 year, the thickness of the corrosion is 0.0004 mm, tantalum into 200 degrees in the sulfuric acid soaked for a year, the surface layer is only damaged 0.006 mm. At 250 degrees Celsius, the corrosion rate increases to 0.116 mm per year.

At 300 degrees, the rate of corrosion is accelerated, soaking 1 year, the surface was corroded 1.368 mm. In fuming sulfuric acid, the corrosion rate is more severe than in concentrated sulfuric acid, and the surface is corroded to a thickness of 15.6 mm after 1 year of immersion in the solution at 130 degrees.

Tantalum uses and applications

  1. Electronic industry:

The dense oxide film formed on the surface of tantalum metal has the one-way conductivity of valve metal, which is suitable for making capacitors with high reliability and long life and is widely used in military equipment and high-tech fields such as missiles, radar, TV, electronic computers, cell phones, etc. In 2000, 24 billion tantalum capacitors were produced worldwide.

  1. Steel industry:

85% ~ 90% of the world’s niobium is used in steel production in the form of Ferro niobium. It is the leading micro-alloying element for niobium steel. When 0.1% of the alloying element is added, the yield strength of steel (N/mm2) increases as follows: niobium 118, vanadium 71.5, molybdenum 40, manganese 17.5, titanium 0. In fact, only 0.03% ~ 0.05% of Nb increases the yield strength of steel by more than 30%. As an alloying element, niobium is mainly used in the production of stainless steel and high strength low alloy steel (HSLA), which is widely used in oil transportation, gas pipelines, the automotive industry, shipbuilding, railroad transportation, construction industry, heavy machinery, and port construction.

  1. Atomic energy industry:

Niobium has the advantages of high melting point, corrosion resistance, and relatively small thermal neutron capture cross-section, suitable for the manufacture of reactor uranium heating elements of the cladding tube and superheater.

  1. Petroleum and chemical industries:

Niobium and tantalum have high corrosion resistance, good strength and processing plasticity and are excellent structural materials for chemical equipment. Used in the production of inorganic acids (nitric acid, sulfuric acid, hydrochloric acid), petroleum refining, and other equipment.

  1. aerospace air industry:

Niobium-tantalum thermal strength alloy has good thermal strength, heat resistance and processing properties, widely used in the manufacture of aerospace air engine parts and gas turbine blades. In the United States, almost all the thermal parts of jet fighter engines are made of niobium alloys.

  1. Cemented carbide:

Tantalum carbide is an important additive to cemented carbide, and its hardness is second only to diamond. Tantalum carbide is widely used in machining, the automotive industry, petroleum, and geological drilling tools, etc.

  1. Superconducting materials:

Some niobium alloys and compounds have high superconducting transition temperatures and are used in the manufacture of various industrial superconductors, such as superconducting generators, gas pedal high-power magnets, superconducting magnetic energy storage devices, nuclear magnetic resonance imaging equipment, etc.

  1. Medical field:

Tantalum and niobium have good biocompatibility and physiological corrosion resistance. Medical tantalum and niobium are used in the manufacture of bone plates, cranial plate screws, implant roots, surgical instruments, etc.

Does Tantalum Have a High Resistance to Corrosion?

Corrosion Resistance of Tantalum

Tantalum has very good corrosion resistance in most inorganic acids, is very similar to glass, and has important uses in the chemical industry. It is resistant to almost all chemical media (including hydrochloric acid at boiling point, nitric acid, and sulfuric acid below 175°C) except hydrofluoric acid, fluorine, fuming sulfuric acid, and alkalis.

tantalum corrosion resistance

Tantalum has excellent corrosion resistance to dilute sulfuric acid below 75% and can be used at any temperature; it can be used at 160~170℃ for concentrated sulfuric acid without inflating; it can be used at 250~260℃ for concentrated sulfuric acid with inflating, and the corrosion increases beyond this temperature. Generally in more than 170 ℃ high-temperature use before the first test research. Tantalum also has good corrosion resistance to phosphoric acid, but if the acid contains a trace of fluorine (>4ppm), the corrosion rate increases.

Tantalum is usually not resistant to corrosion in alkali, it becomes brittle and corrodes more quickly at high temperatures and concentrations.

Tantalum can react with high-temperature gas, O2, N2, H2, etc. can penetrate into the internal to make it brittle, such as contact with the initial ecological H, which will also absorb hydrogen and become brittle. Therefore, tantalum equipment should not be in contact with more reactive metals (such as Fe, Al, Zn), because it is easy to constitute a tantalum-iron (Al, Zn) primary battery, and the hydrogen generated by the primary battery reaction will destroy the tantalum cathode and make the equipment fail.

If a small piece of platinum is connected to tantalum with a very small over-voltage of hydrogen, then all the hydrogen will be released on the platinum and the destruction of tantalum by hydrogen can be avoided.

Tantalum has excellent corrosion resistance but is expensive, so its applications are mainly in the form of composite plates and linings, and in order to reduce costs, the thickness of the tantalum layer wants to be as thin as possible, so composite plates or lining welding is very difficult, because the melting point of tantalum and steel is very different, (the melting point of tantalum is 2996 ℃, the melting point of steel is 1400 ℃) and Fe and Ta at high temperatures will form Fe2Ta brittle Intermetallic compounds if the measures are not appropriate, it is easy to lead to cracking of the weld.

The performance of tantalum capacitors

Tantalum electrolytic capacitors have excellent performance and are small in size among all capacitors but can achieve large electric capacity, so they are easy to be made into small chip components suitable for surface mounting.

The tantalum capacitors currently produced are sintered solid, foil-wound solid, and sintered liquid, of which sintered solid accounts for more than 95% of the total production at present, and the non-metal sealed resin package is the main body.

Tantalum electrolytic produces the working environment medium for capacitors is an extremely thin layer of tantalum pentoxide film that is generated on the surface of tantalum metal material. This layer of the oxide film medium is combined with one of the terminals that make up the capacitor as a whole and cannot exist alone, so the electric capacity per unit volume is particularly large, i.e., the specific capacity is very high, so it is particularly suitable for miniaturization.

During the operation of the tantalum electrolytic capacitor, it has the performance of automatic repair or isolation of oxide film defects, so that the oxide film dielectric is strengthened at any time and its proper insulation capacity is restored without continuous accumulation of damage. This performance with unique self-healing technology ensures the advantage of long life and reliability.

Preparation of Tantalum Metal Powder

Preparation methods of tantalum

Smelting method: Tantalum and niobium ore is often accompanied by a variety of metals, and the main steps of tantalum smelting are decomposition of the concentrate, purification, and separation of tantalum and niobium to produce pure compounds of tantalum and niobium, and finally the metal.

Preparation of Tantalum

Ore decomposition can be used hydrofluoric acid decomposition method, sodium hydroxide melting method and chlorination method, etc. Separation of tantalum and niobium can use a solvent extraction method, step-by-step crystallization method, and ion exchange method.

Separation: Firstly, the tantalum-niobium iron ore concentrate is decomposed with hydrofluoric acid and sulfuric acid tantalum and niobium are dissolved in the leaching solution as fluorotantalic acid and fluoronobotic acid, while the associated elements such as iron, manganese, titanium, tungsten, and silicon are also dissolved in the leaching solution, forming a strongly acidic solution with a very complex composition.

The tantalum-niobium leach solution is extracted with methyl isobutyl ketone and extracted into the organic phase at the same time, and the organic phase is washed with a sulfuric acid solution to obtain the pure organic phase containing tantalum-niobium and the extracted residue combined, which contains trace tantalum-niobium and impurity elements, and is a strongly acidic solution, which can be recovered comprehensively.

The pure organic phase containing tantalum-niobium is back-extracted with a dilute sulfuric acid solution to obtain the organic phase containing tantalum. Niobium and a small amount of tantalum enter the aqueous phase and then the tantalum is extracted with methyl isobutyl ketone to obtain a pure niobium-containing solution.

The pure organic phase containing tantalum is then back-extracted with water to obtain a pure tantalum-containing solution. The organic phase after the reverse tantalum extraction is returned to the extraction cycle.

Pure tantalum fluoride solution or pure niobium fluoride solution reacts with potassium fluoride or potassium chloride to form potassium tantalum fluoride (K₂TaF₇) and potassium niobium fluoride (K₂NbF₇) crystals, respectively, and can also react with ammonium hydroxide to form tantalum hydroxide or niobium hydroxide precipitates. Tantalum or niobium hydroxide is calcined at 900~1000°C to produce tantalum or niobium oxide.

Preparation of tantalum.

Tantalum metal powder can be produced by the thermal reduction of metal (sodium thermal reduction) method. The reduction of potassium fluorotantalate with sodium metal in an inert atmosphere: K2TaF7+5Na─→Ta+5NaF+2KF. The reaction is carried out in a stainless steel tank, and the reduction reaction is rapidly completed when the temperature is heated to 900℃. The tantalum powder made by this method is irregular in particle shape and fine in size, which is suitable for making tantalum capacitors.

Tantalum metal powder can also be made by electrolysis of molten salt: using the molten salt of potassium fluorotantalate, potassium fluoride, and potassium chloride mixture as the electrolyte to dissolve tantalum pentoxide (Ta2O5) in it, and electrolysis at 750℃, tantalum powder with a purity of 99.8~99.9% can be obtained.

Tantalum metal can also be obtained by reducing Ta2O5 with carbon heat. Reduction is generally carried out in two steps: first, a certain ratio of Ta2O5 and carbon mixture in a hydrogen atmosphere at 1800 ~ 2000 ℃ to make tantalum carbide (TaC), and then TaC and Ta2O5 in a certain ratio of the mixture of vacuum reduction into tantalum metal.

Tantalum metal can also be produced by thermal decomposition or hydrogen reduction of tantalum chloride. Dense tantalum metal can be prepared by vacuum arc, electron beam, plasma beam melting, or powder metallurgy. High-purity tantalum single crystals are produced by crucible-free electron-beam regional melting.

Is Niobium Similar to Tantalum?

The answer is YES.

uses of tantalum niobium

Tantalum and niobium are inseparable in nature, why can’t they be used as a beautiful symbol of love?

Niobium and tantalum are in the same group in the periodic table and have very similar physical and chemical properties. They are often “inseparable” in nature, like a pair of “twin brothers”.

When niobium and tantalum were discovered in the early 19th century, they were thought to be one element, and it was only after about 42 years that they were separated for the first time by chemical analysis, and it became clear that they were two different metallic elements.

Tantalum (Ta) niobium (Nb) are high melting point (tantalum 2996 ° C, niobium 2468 ° C), high boiling point (tantalum 5427 ° C, niobium 5127 ° C) rare metals, the appearance of steel, gray-white luster, the Tantalum powder is dark gray, with gas absorption, corrosion resistance, superconductivity, unipolar conductivity and high strength at high temperatures, and other characteristics.

Therefore, the current tantalum niobium new material applications related to high-tech industrial fields include electronics, precision ceramics, and precision glass industry; electro-acoustic optical devices; cemented carbide, astronautics, and electronic energy industry; biomedical engineering; superconductivity industry; special steel and other industries.

Niobium-tantalum has good resistance to physiological corrosion and biocompatibility and does not interact with body tissues, so it is often used in the manufacture of bone plates, skull plate bone screws, dental implant roots, surgical appliances, etc. Tantalum is also known as a “biophilic metal” because it replaces bone in the human body with tantalum strips on which muscles can grow.

This is why they are also known as “pro-biological metals”. Therefore, there are no allergies when using them for rings, and the price is better. Because tantalum is almost twice as dense as niobium, a tantalum ring of the same size will be more textured, darker in color, and more expensive than a niobium ring.

Because they have always coexisted in nature, we can also define them as a good brother or a loving couple who are inseparable, if you want to buy a pair of rings you can consider buying one each of tantalum and niobium for better meaning.