Basic Knowledge of Refractory Metal Tantalum

Tantalum Overview

Tantalum is part of the refractory metal group and it has good physical and chemical properties.

Tantalum has high hardness that can reach 6-6.5. Its melting point is as high as 2996 ° C, only after carbon, tungsten, rhenium and osmium. Tantalum is malleable and can be drawn into a thin foil. Its coefficient of thermal expansion is very small, and it only expands by 6.6 parts per million per degree Celsius. In addition, it has a strong toughness and is superior to copper.

Refractory Metal tantalum
Refractory Metal Tantalum

Tantalum does not react with hydrochloric acid, concentrated nitric acid and “aqua regia” under both cold and hot conditions. And tantalum is only corroded by concentrated sulfuric acid at temperatures above 150 °C. Tantalum can be considered one of the most chemically stable metals at temperatures below 150 °C. It is also highly resistant to corrosion because of the formation of a stable tantalum pentoxide (Ta2O5) protective layer on its surface.

Tantalum Application

Tantalum can be used to manufacture evaporation vessels, as well as tubes, rectifiers, and electrolytic capacitors. Tantalum forms a stable anodized film in an acidic electrolyte. The electrolytic capacitor made of tantalum has the advantages of large capacity, small size and good reliability. Tantalum capacitors are the most important use of tantalum, around 2/3 of the full use of tantalum. Tantalum is also the material for making electron-emitting tubes and high-power tube parts. Anti-corrosion equipment made by Tantalum is used in the chemical industry such as strong acid, bromine and ammonia producing industries. The metal tantalum can be used as a structural material for the combustion chamber of an aircraft engine. Tantalum is easy to form and can be used as support accessories, heat shields, heaters and heat sinks in high temperature vacuum furnaces. Tantalum can also be used as orthopedic and surgical materials. Tantalum sputtering targets and tantalum evaporation materials are important coating materials in physical vapor deposition.

tantalum capacitor
tantalum capacitor

High Purity Tantalum Preparation

The chemical inertness and relatively low price of tantalum make it a good alternative to platinum.  However, high-purity tantalum is not easy to get because it is always found together with niobium in the mineral groups of tantalite, columbite, and coltan. To get high purity tantalum, here are several methods.

1 Tantalum powder can be obtained by metal thermal reduction (sodium thermal reduction) method. The potassium fluotantalate is reduced with sodium metal under an inert atmosphere: K2TaF7 + 5Na-→Ta+5NaF+2KF. The reaction was carried out in a stainless steel tank, and the reaction was quickly completed when the temperature was heated to 900 °C. The powder prepared by this method has irregular grain shape and fine particle size, and is suitable for making tantalum capacitors.

2 The tantalum powder can also be obtained by molten salt electrolysis: a molten salt of a mixture of potassium fluoroantimonate, potassium fluoride and potassium chloride is used as an electrolyte, and tantalum pentoxide (Ta2O5) is dissolved therein and electrolyzed at 750 °C. This method can obtain a bismuth powder having a purity of 99.8 to 99.9%.

3 Tantalum can also be obtained by carbothermal reduction of Ta2O5. The reduction is generally carried out in two steps: first, a mixture of a certain ratio of Ta2O5 and carbon is made into tantalum carbide (TaC) at 1800 to 2000 ° C in a hydrogen atmosphere. Then, TaC and Ta2O5 are prepared into a mixture in a certain ratio, and reduced to tantalum in a vacuum.

4 Tantalum can also be obtained by thermal decomposition or hydrogen reduction of chloride. The dense metal crucible can be prepared by vacuum arc, electron beam, plasma beam melting or powder metallurgy.

Please visit https://www.sputtertargets.net/ for more information.

How was tantalum discovered? | History of Tantalum

In the middle of the 17th century, a very heavy black mineral (density of SAM®Tantalum is 16.68 g/cm3) found in North America was sent to the British Museum for safekeeping. After about 150 years, in 1801, British chemist Charles Hatchett accepted the ore analysis task from the British Museum. He discovered a new element and named it Columbium (later renamed Niobium) to in honor of the place where the mineral was first discovered – Colombia.

Tantalum

In 1802, when the Swedish chemist Anders Gustaf Ekberg analyzed their minerals (the niobium-tantalum ore) in Scandinavia, he discovered a new element. He named it Tantalum, referring to the name of Tantalus, the son of Zeus God in Greek mythology.

Because Niobium and Tantalum are very similar properties, they were once thought to be the same element. In 1809, the British chemist William Hyde Wollaston compared the Niobium oxide and Tantalum oxide. Although they gave different density values, he still believed that the two were identical substances.

Tantalum Discovery History

By 1844, the German chemist Heinrich Rose refuted the conclusion that Niobium and Tantalum were the same elements, and proved that they are two different elements through chemical experiment. He named the two elements “Niobium” and “Pelopium” in the name of the Greek mythology of Tantalus’s daughter Niobe (the goddess of tears) and the son of Pelops.

In 1864, Christian Wilhelm Blomstrand, Henry Edin St. Clair Deville and Louis Joseph Troost clearly proved the Tantalum and Niobium are two different chemical elements ,and determined the chemical formula of some related compounds. In the same year, Demarinia heated tantalum chloride in a hydrogen atmosphere, and got tantalum metal for the first time through a reduction reaction. Early tantalum metals contain many impurities, and it was not until 1903 that Werner von Bolton first made pure tantalum metal.

This is a history column of SAM Sputter Target, aiming at introducing the history of different metals. If you are a metal lover or history lover, you can follow our website. For previous posts of metal history, you can search the keyword “history”.

Please visit https://www.sputtertargets.net/ for more information.

How is tantalum used in phones?

We have talked about the Application of Tantalum Target in Thermal Inkjet Print Head and Copper Plating before, which rises your interest on this element. However, most people think thermal inkjet print and copper plating are far away from their life, thus are difficult to understand. So today, SAM sputter targets will talk about something that EVERYONE is familiar with—your mobile phones.

tantalum

Tantalum is a very important element in the electronic industry. And it is widely used in all kinds of electronic devices, such as phones and computers. The main use of tantalum materials in electronic products comes in the creation of tantalum capacitor. Tantalum capacitors have their unique advantages over other capacitors. They do not use electrolytes like ordinary electrolytic capacitors, making them ideal for operation at high temperatures. Solid tantalum capacitors have excellent electronic properties, wide operating temperature range, various forms and excellent volumetric efficiency.

Continue reading “How is tantalum used in phones?”