Tantalum oxide (Ta2O5) is a versatile and useful material with a range of applications. One of the most significant uses of tantalum oxide is in the production of capacitors, where it is used as a dielectric material due to its high dielectric constant [1]. Tantalum oxide is also commonly used as a coating material, thanks to its high refractive index and low absorption properties. This makes it a popular choice for optical coatings, including anti-reflective coatings for lenses and mirrors [1].
In addition to its use in capacitors and coatings, tantalum oxide is also used as a functional material in combination with sensors and biochemical materials [2]. This has led to a wide range of applications in fields such as biotechnology and environmental monitoring. For example, tantalum oxide can be used as a sensing material in gas sensors and biosensors [2].
Another application for tantalum oxide is in the production of mobile phone capacitors [3]. These components are critical for the functioning of mobile phones, as they store electrical charge and control the flow of current. Tantalum oxide is often used in combination with powdered tantalum to produce these capacitors [3].
Overall, tantalum oxide is a highly versatile and useful material with a range of applications. Its unique properties make it ideal for use in capacitors, coatings, sensors, and other functional materials.
Tantalum oxide (Ta2O5) is a chemical compound that has been widely used in the field of electronics and optics due to its excellent properties, including a high refractive index, good thermal stability, and excellent dielectric properties. However, the question remains: is tantalum oxide a semiconductor?
The short answer is yes, tantalum oxide can exhibit semiconductor properties, but it depends on its composition and processing. Tantalum oxide can exist in different crystal structures, and the electrical properties of each structure can vary significantly. In its amorphous form, tantalum oxide behaves like a high-k dielectric material, meaning it has a high capacitance but low conductivity. However, when tantalum oxide is doped with certain impurities, it can exhibit semiconductor behavior.
One of the most common dopants used in tantalum oxide is niobium (Nb). Nb-doped tantalum oxide (TaNbO) has been extensively studied for its potential as a resistive switching material in non-volatile memory devices. In these devices, a thin layer of TaNbO is sandwiched between two metal electrodes. When a voltage is applied, the TaNbO layer undergoes a phase change from an insulating to a conductive state, allowing for data storage.
Another example of tantalum oxide exhibiting semiconductor behavior is in the form of nanocrystals. Tantalum oxide nanocrystals can be synthesized with a variety of sizes and shapes and have shown potential as a photocatalyst in solar cells. When excited by light, the nanocrystals can generate electron-hole pairs, leading to a photocurrent that can be used to generate electricity.
In addition to its potential in electronics and optics, tantalum oxide’s semiconductor properties also make it a promising material for sensing applications. TaNbO-based sensors have been developed to detect gases such as hydrogen and ammonia. These sensors work by measuring changes in the electrical conductivity of the TaNbO layer in the presence of the target gas.
In conclusion, tantalum oxide can exhibit semiconductor properties depending on its composition and processing. Doped tantalum oxide and tantalum oxide nanocrystals have shown potential in various applications, including non-volatile memory devices, solar cells, and sensors. With further research and development, tantalum oxide may find even more applications in the field of electronics and beyond.
– Sputtering barrels: Computer disk manufacturers and other industries that use sputtering processes are increasingly using tantalum to resist corrosion in sputtering barrels. The tantalum lining process is more environmentally friendly than chromium lining, helping the industry reduce its ecological impact.
– Machined fasteners: Machined fasteners made from tantalum offer excellent corrosion resistance. They replace fasteners made from alternative materials that are prone to failure or require expensive equipment downtime for maintenance. Tantalum fasteners are found in industries such as mining, energy, and pharmaceuticals, as well as in metal and chemical processing.
– X-ray/radiation shielding: Tantalum’s radiopaque properties make it ideal for X-ray and shielding applications that seek to prevent radiation leakage. Tantalum shielding can also protect sensitive electronic components in aerospace structures as well as components operating in corrosive environments.
– Vacuum furnace heating elements: Many vacuum furnace components contain tantalum rods due to tantalum’s oxidation resistance and high melting point. Tantalum’s temperature particle stability increases the life expectancy of the machine, as it can withstand high temperatures for extended periods of time.
– Machined parts for chemical processing equipment: Tantalum’s corrosion-resistant properties make it the material of choice for machined parts for chemical processing equipment. Tantalum machined parts replace inferior materials that perform poorly in harsh chemical environments and require extensive maintenance.
– 7: Tantalum ingots: used for sputtering targets, high-temperature alloys, computer hardware drive discs, and TOW-2 bomb-forming projectiles
Together with tungsten carbide WC and titanium carbide TIC, tantalum carbide TAC is a cemented carbide component used in cutting and drilling tools.
Tantalum is particularly suitable for heat exchangers; it has high thermal conductivity and its surface properties prevent the formation of adhesive deposits.
Manufacture of furnace components such as screens, supports, and crucibles. The alloying elements in high-temperature alloys increase high-temperature strength. It is biologically inert and can be used for implants, needles, etc. Yttrium tantalate YTAO4 is used in medical diagnostics.
SAM offers our customers a wide selection of tantalum rods, tubes, sheets, and wires, all designed for a variety of applications. Our products are cold rolled and annealed in a proprietary process to create machined parts with metallurgical properties ideal for applications such as sputtering gun tubes, processing into fasteners, X-ray radiation shielding, development rings, vacuum furnace heating elements, chlorinator springs, assemblies, and more for light bulbs or chemical processing equipment.
The atomic sequences of tantalum (Ta) and niobium (Nb) are 73 and 41, respectively, both of which are located in the VB family of excessive elements. They are often symbiotic in nature and are important refractory rare metals. They look like steel, with off-white luster, and the powder is dark gray. They have excellent properties, including a high melting point, high boiling point, low vapor pressure, good cold workability, high chemical stability, strong resistance to liquid metal and acid and alkali corrosion, and high dielectric constant of the surface oxide film, etc.
Tantalum and niobium metals and their compounds and alloys are important functional materials, which has important applications in the technical fields of electronics, steel, metallurgy, chemicals, hard alloys, atomic energy, aerospace, and other industrial sectors as well as strategic weapons, superconducting technology, scientific research, medical devices and so on.
Applications of tantalum and niobium
Tantalum and niobium are similar in nature and can be replaced in many application areas. However, their respective characteristics have led to the use of tantalum in industries such as electronics, metallurgy, chemicals, and hard alloys.
Electrolytic capacitors made of tantalum metals in the electronics industry have outstanding characteristics such as large capacitance, small leakage current, good stability, high reliability, good pressure resistance, long life, and small volume. They are widely used in national defense, aviation and aerospace, electronic computers, high-end civilian electrical appliances, and electronic circuits of various electronic instruments. Niobium is used in industrial-grade superconducting technology such as steel, ceramics, and nuclear energy.
In today’s world, about 65% of the total tantalum is used in the electronics industry, and about 87% of the total niobium is used in the steel industry. With the advancement of technology, the application fields of tantalum and niobium and their alloys and processed materials will continue to expand.
Tantalum can store and release energy, which is indispensable in the electronics industry, so tantalum capacitors consume more than half of the world’s mine production.
The tantalum-based components can be made very small, and other chemical elements cannot be used as substitutes without degrading the performance of the electronic device, so tantalum is almost ubiquitous as a component application, such as mobile phones, a hard disks, and a hearing aid.
In the chemical industry, the corrosion resistance of tantalum is very good and it is used as a lining for pipelines and tanks. Tantalum carbide has a high hardness and is an ideal material for manufacturing cutting tools, and tantalum oxide can increase the refractive index of glass lenses.
Current supply and demand situation
Before the end of 2011, the industry was generally operating in a benign environment. The front end of tantalum niobium production has a large space, the intermediate wet smelting and fire smelting also have a certain profit, and the back end high specific volume of tantalum powder and tantalum wire production and sales market also has a large operation space. However, since the second half of 2012, with the emergence of the global financial crisis, such applications as tantalum niobium are relatively narrow and the consumer sector has been greatly affected by the high-end electronic products industry.
The trend of the tantalum niobium market
At present, the production in the tantalum niobium industry is mainly based on wet smelting and pyrometallurgical smelting. The products produced are mainly potassium fluoroantimonate, antimony oxide, antimony oxide, antimony carbide, antimony wire, metallurgical grade tantalum powder, and some coffin materials.
At present, the domestic demand for tantalum niobium is 800~1000 tons, and the national production capacity is about 140~150 tons. Most of the rest of the raw materials are all dependent on African imports.
Most of the exported antimony mines in Africa are also known as “African blood mines”, which refer to war-plunging low-cost minerals that are arbitrarily harvested and dug in the African region at the expense of polluting the environment and destroying resources. African mines are affected by the instability of the regional political and economic environment and have greater volatility. Its products contain high levels of unfavorable elements such as antimony, uranium, and thorium, which have certain adverse effects on product quality and environmental protection requirements of downstream products; Moreover, the delivery period of the mine is long and the safety cannot be fully guaranteed. To this end, the International Electron Association has classified it as a source of minerals that are not allowed to enter the normal market.
Stanford Advanced Materials supplies high-quality tantalum niobium products to meet our customers’ R&D and production needs. Please visit https://www.samaterials.com/ for more information.
Tantalum is a shiny, silvery metal that is soft when is pure. It is almost immune to chemical attacks at temperatures below 150℃. Tantalum is virtually resistant to corrosion due to an oxide film on its surface.
Applications of tantalum
Tantalum is used to manufacture surgical implants, capacitors, aircraft engines, and alloys. It is used to produce high-temperature devices because of its high melting point. The element also has application in the chemical industry because of its good corrosion resistance. It is used to manufacture refractive index glass, electron tubes, and alloys for missiles, nuclear reactors, chemical equipment, and jet engines.
However, the element is rarely added to alloys because it makes some metals more brittle. Tantalum is used to manufacture tubes because it forms oxides and nitrides that create the vacuum. In addition, it is used to manufacture special optical glasses, non-ferrous alloys for aerospace and nuclear applications, metallurgical and chemical processing equipment, high-voltage surge arresters, and more. It is also used to make circuitry for devices and computers, electrolytic capacitors, and tantalum compounds and alloys. Glass-line equipment is also manufactured. Its compounds are used to produce clips, mesh, surgical equipment, and machinery.
The harm of tantalum
Tantalum powder is not as serious as other metals (zirconium, titanium, etc.), but it has the risk of fire and explosion.
Tantalum-related jobs often carry the risk of burns, electric shocks, eyes, and trauma. The refining process involves toxic and dangerous chemicals such as hydrogen fluoride, sodium, and organic solvents.
Toxicity
Both tantalum oxide and tantalum metal have low systemic toxicity, which may be due to their poor solubility. However, there are also skin, eye, and respiratory hazards. In alloys of cobalt, tungsten, and niobium, tantalum is considered to be the cause of pneumoconiosis and skin damage caused by hard metal dust.
Tantalum hydroxide has no toxic effect on chicken embryo, and intraperitoneal injection of tantalum oxide has no toxic effect on rats. However, when tantalum chloride has an LD50 of 38mg/kg(Ta), the compound salt K2TaF7 is about one-fourth toxic.
Safety precautions
In most operations, general ventilation can maintain the dust concentration of tantalum and its compounds below the exposure limit. Flame, arc, and spark should be avoided in the area where tantalum powder is handled. If workers are regularly exposed to dust concentrations close to the critical value, regular physical examinations should be conducted, with emphasis on lung function. For operations containing tantalum fluoride and hydrogen fluoride, precautions applicable to these compounds should be followed.
Tantalum bromide (TaBr5), tantalum chloride (TaCl5), and tantalum fluoride (TaF5) shall be stored in a clearly labeled and cool, ventilated place away from compounds affected by acid or acid smoke, and the persons concerned should be reminded of the danger.
Stanford Advanced Materials supplies high-quality tantalum products to meet our customers’ R&D and production needs. Please visit https://www.samaterials.com/ for more information.
The most useful tantalum oxide is tantalum pentaoxide (Ta2O5). Ta2O5 is white fine crystal powder, tasteless and odorless, with a specific gravity of 8.71g/cm3 and a melting point of 1870℃. Tantalum is amphoteric but apparently acidic, insoluble in water, most acids, and bases, but slowly dissolved in hot hydrofluoric and peroxy acids.
Ta2O5 has both α and βvariants, and its transition temperature is 1320℃, beyond which Ta2O5 turns white to gray. Different oxides have different crystal structures, so their lattice constants, densities, and other properties are obviously different. It is known that amorphous Ta2O5 begins to crystallize at 500℃ to form a low-temperature crystal (T type), converts to a temperature crystal (M type) at 830℃, and forms a high-temperature crystal (H type) at more than 830℃.
Tantalum halide
In tantalum halides, halogens in high-priced pentahalides are more easily replaced by oxygen to form stable halogen oxides. Most of the halogens of tantalum are volatile compounds, among which fluoride is well soluble in water and only partially hydrolyzed.
Tantalum(V) chloride (TaCl5) is a white powder and yellow when it is not pure. It has a melting point of 220℃, a boiling point of 223℃-239℃, and a specific gravity of 3.68g/cm3. It is volatile and has strong moisture absorption. It is unstable at high temperatures and decomposes to form metal tantalum at vacuum temperatures above 800℃. In addition to the high-priced TaCl5, the low-priced chlorides of tantalum include TaCl4, TaCl3, and TaCl2, which are volatile substances.
Tantalum bromide (TaBr5) is an orange crystal, soluble in water and hydrolyzed, soluble in methanol, ethanol, and CCl4, and soluble in aniline and liquid ammonia for reactions. Tantalum iodide (TaI5) is a black crystal that can be heated to sublimate without decomposition and readily hydrolyzes in moist air, releasing hydrogen iodide.
Tantalum carbide
Ta2C and tantalum carbide (TaC) are the main carbides of tantalum, and Ta2C has both alpha -Ta2C and beta -Ta2C isomers. TaC is a dark brown powder with a melting point of 3880℃, a boiling point of 5500℃ and a density of 14.4g/cm3. It has good chemical stability and can only be dissolved in mixed solutions of nitric acid and hydrofluoric acid. The carbide of tantalum is not easy to be oxidized in the air when the temperature is lower than 1000 ~ 1100℃. Nitrogen compounds are readily formed by the action of nitrogen or ammonia.
Tantalum hydride
Tantalum hydrides are very stable at room temperature in the air. Hydrogen is released by decomposition when heated to 1000 ~ 1200℃ under a high vacuum. Below 350℃, tantalum almost has no interaction with hydrogen, and the reaction speed increases with the increase of temperature. At a certain temperature and pressure, the maximum hydrogen content in tantalum hydride corresponds to H/Ta of 0.02 ~ 0.08(TaH0.2 ~ TaH0.8).
Tantalum nitride
There are three kinds of tantalum nitride: TaN, Ta2N, and Ta3N5. Tantalum nitrite is a bluish-gray powder with a melting point of 2980 ~ 3090℃ and a density of 14.4g/cm3. It is insoluble in nitric acid, hydrofluoric acid, and sulfuric acid, but soluble in hot alkaline solution and releases ammonia or nitrogen. Tantalum nitride generates oxides when heated in air, releasing nitrogen.
Tantalum selenite
TaSe2, its resistivity is 2.23 x 10-3 Ω. Cm, with the relative friction coefficient of 0.08 in the air at room temperature, the oxidation temperature of 600 ℃ in air, and the decomposition temperature of 900 ℃ in a vacuum.
Tantalum silicone
The main silicide of tantalum is TaSi2, and there are also some other compounds such as Ta2Si and Ta5Si3. Ta2Si has a melting point of 2200 ℃, a density of 8.83 g/cm3 and a resistance of 8.5 Ω. Cm. It is not eroded by mineral acids, but can be decomposed by hydrofluoric acid, and can be completely decomposed by molten Na2CO3 and NaOH.
Tantalate
Ta2O5 can be fused with oxides, hydroxides, or carbonates of more than 50 elements from all 8 groups in the periodic table of chemical elements to form various complex types of tantalates, which may be expressed in the following general formula: xMeO•yTa2O5 (Me = alkali metal).
Almost all alkali tantalates have a high degree of polymerization in aqueous solution and are insoluble compounds in water solution. Alkali tantalate can be reduced by hydrogen: 2MeTaO3+H2=Me2O+2TaO2+H2O, with a reaction temperature of 600~700℃. Except for alkali tantalates, most tantalates are insoluble in water.
Most tantalate crystals (such as lithium tantalate) are ferroelectric. They belong to the category of thermoelectric devices that have spontaneous polarization. Their polarization value is related to electric field voltage and has Curie temperature. Tantalum ferroelectric materials also have the characteristics of voltage, electro-optic and nonlinear optics. Some tantalates are semiconductor materials with narrow channels and are important materials for manufacturing electronic industrial components.
Stanford Advanced Materials supplies high-quality tantalum products to meet our customers’ R&D and production needs. Please visit http://www.samaterials.com for more information.
If you want to know why the electrolytic capacitor explodes, first you have to know what the electrolytic capacitor is. An electrolytic capacitor is a kind of capacitance. The metal foil is the positive electrode (aluminum foil or tantalum foil), and the oxide film (aluminum oxide or tantalum oxide), which is closely attached to the metal, is the dielectric. The cathode consists of conductive material, electrolyte (which can be liquid or solid), and other materials. Because the electrolyte is the main part of the cathode, the electrolytic capacitor is hence named. At the same time, the capacitance of the electrolytic capacitor cannot be connected wrongly.
Tantalum electrolytic capacitor mainly consists of sintering solid, foil winding solid, sintering liquid, and so on. The sintered solids account for more than 95% of the current production and are mainly composed of non-metallic sealed resin.
The aluminum electrolytic capacitor can be divided into four types: the lead type aluminum electrolytic capacitor; Horn type aluminum electrolytic capacitor; Bolted aluminum electrolytic capacitor; Solid aluminum electrolytic capacitor.
The possible reasons for the capacitor explosion are as follows:
The breakdown of the internal components of the capacitor is mainly due to the poor manufacturing process.
The capacitor is damaged by insulation to the shell. The high voltage side of the capacitor is made of a thin steel sheet. If the manufacturing process is poor, the edge is uneven with burr or serious bend. The tip is prone to corona, and the corona causes the breakdown of oil, the expansion of the case and the drop of oil. In addition, when the cover is closed, if the welding time is too long, the internal insulation burns and produces oil and gas, causing the voltage to drop greatly and damage.
Poor sealing and oil leakage. The insulation resistance is reduced due to the poor sealing of the assembly casing. Or the oil spill caused the oil surface to drop, resulting in the extreme shell direction discharge or component breakdown.
The belly and the inside dissociate. Due to the internal corona, breakdown discharge, and serious dissociation, under the action of overvoltage, the starting free voltage of the element is reduced to the working electric field intensity. This causes the physical, chemical and electrical effects to accelerate the aging and decomposition of the insulation, producing gas and forming a vicious circle, the pressure of the case is increased, causing the drum to explode
A capacitor explodes with an electric charge. All capacitors with rated voltages are forbidden to be charged. Each time the capacitor bank recloses, the capacitor must be discharged for 3min after the switch is disconnected. Otherwise, the voltage polarity of the closing moment may be caused by the opposite polarity of the residual charge on the capacitor. For this purpose, a capacitor bank with a capacity of more than 160kvar is generally required, and automatic tripping device should be installed when there is no pressure. And the capacitor bank switches are not allowed to install automatic reclosing.
In addition, it may be caused by high temperature, poor ventilation, high operating voltage, excessive voltage harmonic component or operating overvoltage, etc.
Tantalum oxide is shown to be chemically very robust. Reactively sputtered tantalum oxide thin films have been investigated as a protective coating for aggressive media exposed sensors.
The step coverage of the sputter-deposited amorphous tantalum oxide is reasonable, but metallization lines are hard to cover. Sputtered tantalum oxide exhibits high dielectric strength and the pinhole density for 0.5 pm thick films is below 3 cm.
Applying protective coatings as a solution to this sensor concept requires a number of properties for the coating to fulfill, a short list includes:
Corrosion resistance: the maximum allowable thickness of the coating and minimum required lifetime sets the upper limit of the etch rate in the media of interest.
Low residual stress in small thickness: to limit the reduction of sensitivity due to stiffness changes in the membrane.
Step coverage: poor coverage over interconnects and contact windows are sites where degradation of the sensor will initiate.
Pinhole density: usually no pinholes are allowed in the exposed area of the sensor. Etchants will penetrate the coating and degrade electrically active components or under etch, eventually resulting in an undesired lift-off of the coating. In case the pinholes are due to particulate contamination, the pinholes may be eliminated by growing thicker films.
Electrical properties: a dielectric film is required to insulate electrical components on the sensor from electrically conducting media.
Patternable: in many cases, it is desired to pattern the protective coating for access to bond pads. Patterning in a batch process, such as wet etching, is preferred.
Double-sided deposition for protection of both sides of the differential pressure sensor.
Coverage of sharp corners: a conformal coating is required.
Coverage of deep cavities: a conformal coating is required down to the bottom of the cavity.
The use of tantalum, tantalum alloys, and tantalum oxide has already been suggested for sensor purposes. Besides, tantalum is used in chemical processing equipment because it is extremely stable. The reason for this is the formation of a thin amorphous tantalum oxide layer at the surface, which is chemically very inert.
Deposition of tantalum and its oxides and nitrides can be done by physical vapor deposition, chemical vapor deposition, or by thermal oxidation. This makes the use of these materials very flexible.
Tantalum electrolytic capacitors are widely used in communications, computers, aerospace, and military, as well as advanced electronic systems, portable digital products, and other fields.
Tantalum electrolytic capacitor is made of tantalum (Ta) metal as anode material, which can be divided into foil type and tantalum powder sintered type according to different anode structures. Among tantalum powder sintered tantalum capacitors, there are tantalum capacitors with solid electrolytes and tantalum capacitors with non-solid electrolytes due to different electrolytes. The shell of tantalum electrolytic capacitors is marked with CA, but the symbol in the circuit is the same as that of other electrolytic capacitors. Compared with aluminum electrolytic capacitors, tantalum electrolytic capacitors have the following advantages.
Tantalum-Electrolytic-Capacitors
Small volume
Because tantalum electrolytic capacitors are made of very fine tantalum powder, and the dielectric constant of the tantalum oxide film is higher than that of the alumina oxide film, the capacitance per unit volume of tantalum electrolytic capacitors is large.
Wide temperature range for use
Tantalum electrolytic capacitors commonly can work normally at the temperature of -50 ℃~100 ℃. Although the aluminum electrolytic capacitor can also work in this range, its electrical performance is not as good as that of the tantalum electrolytic capacitor.
Long life, high insulation resistance, and small leakage current
Tantalum oxide film in tantalum electrolytic capacitors is not only corrosion-resistant but also can maintain good performance for a long time.
Good impedance frequency
For capacitors with poor frequency characteristics, the capacitance will drop sharply and the loss (tg delta) will also rise sharply when the working frequency is high. However, solid tantalum electrolytic capacitors can operate above 50kHz. When the frequency of the tantalum electrolytic capacitor increases, the capacity will also decrease but by a small margin. The data show that the tantalum electrolytic capacitor capacity decreases by less than 20% at 10kHz, while the aluminum electrolytic capacitor capacity decreases by more than 40%.
High reliability
Tantalum oxide film has stable chemical properties. In addition, Ta2O5 anode substrate of tantalum can withstand strong acid and pressure, so it can use a liquid electrolyte with low resistivity of solid or acid. In this way, tantalum electrolytic capacitors have less loss than aluminum electrolytic capacitors and have good temperature stability.
Chip tantalum electrolytic capacitors are made of highly pure and extremely small homogeneous particles, which are characterized by small size, large capacity, and high frequency. In recent years, chip tantalum electrolytic capacitors have been widely used in mobile phones, DVDs and other consumer electronic products.
Tantalum is a metal element with the element symbol of Ta, an atomic number of 73, a density of 16.68g/cm, and a melting point of 2980 DEG C. Pure tantalum with blue color and excellent ductility can be rolled into a very thin plate in the cold state without intermediate annealing.
Tantalum has a series of excellent properties such as high melting point, low vapor pressure, and cold processing performance, high chemical stability, anti-corrosion ability, constant liquid metal oxide film, which has important applications in electronics, metallurgy, chemical industry, aerospace, medical health, and scientific research and other high-tech fields.
Discovery history
In the middle of the Seventeenth Century, a heavy black mineral was found in North America and was sent to the British Museum. After about 150 years, until 1801, the British chemist C.Hatchett accepted the analysis task of the ore in the British Museum, discovered a new element, and named it columbium, which is to commemorate the earliest discovered mineral areas — Columbia.
In 1802, when the Swedish chemist A.G.Ekaberg analyzed a mineral in Scandinavia, making their acid fluoride salt after recrystallization, leading to the discovery of the new element, he named the element tantalum referred to in Greek mythology, Jose Tantalus, the son of God’s name.
Due to the nature of columbium and tantalum being very similar, people once thought that they are the same kind of elements. In 1809, the British chemist William Hyde Wollaston compared tantalum and Columbium oxide, although different density value, he believes that the two are identical materials.
In 1844, the German chemist Heinrich Rose dismissed the conclusion that tantalum and Columbium are the same element, and identified that they are two different elements by chemical methods. He named them “Niobium” and “Pelopium”.
In 1864, Christian Wilhelm Blomstrand, and Louis Joseph Troost clearly demonstrated that tantalum and niobium are two different chemical elements, and determine the chemical formula of some related compounds. The early tantalum metal has more impurities. Werner von Bolton was first made pure tantalum metal in 1903.
Scientists first extract tantalum from niobium with the method of hierarchical crystallization, which is found by de Marinilla in 1866. Today, scientists are using a solvent extraction method for the solution containing fluoride.
Preparation technology
The preparation of tantalum is the process of reducing pure tantalum compounds to metal tantalum. The raw materials are five tantalum oxide, tantalum chloride, five tantalum fluoride, and fluoride (such as K2TaF7,). The reducing agent is sodium, magnesium, other active metals, and carbon and hydrogen. The melting point of tantalum is as high as 3669K, so it is powder or spongy metal after reduction. It is necessary to further smelting or refining, in order to get dense metal.
The tantalum preparation methods are sodium thermal reduction, carbon thermal reduction, and molten salt electrolysis. Sodium thermal reduction of potassium tantalate is the most widely used method of tantalum production in the world.
The tantalum powder has a complex shape and a large specific surface area. Carbon thermal reduction of five oxidation of tantalum has been an industrial method for the production of tantalum, but because the purity of the product is not high enough, is not as widely used as the sodium reduction method. The molten salt electrolysis method is divided into two ways: electrolyte electrolysis and oxygen-free electrolyte electrolysis. Molten salt electrolysis can only produce metallurgical grade tantalum powder. Five hydrogen fluoride reduction is considered to be one of the most promising methods for tantalum production, but it has not been used in industrial production because of the high requirements of equipment material and environmental protection.
The majority of tantalum powder is directly used for tantalum capacitors in the electronic manufacturing industry, so the tantalum milling process, such as the preparation of tantalum metal is also from tantalum and tantalum powder by vacuum heat treatment, capacitor grade tantalum powder hydrogenation method category.
Tantalum-Powder
Production of tantalum powder
Sodium metal thermal reduction method is an important method for the production of tantalum powder, which is the main method of industrial production of tantalum powder (including metallurgical Ta powder). The particle shape of metal tantalum powder with the large surface area is complex, which is suitable for anode material for tantalum electrolytic capacitors by electron beam melting and vacuum arc melting of tantalum or tantalum sintered in vacuum refining, then the high purity tantalum rod made and then processed into a variety of tantalum.
Since the 1970s, it has been widely used to increase the specific capacitance of tantalum powder. The commonly used doping agent is phosphate, which can be mixed before or after the crystallization of potassium fluoride and can be added before the vacuum heat treatment of tantalum powder. The doping can prevent the sintering of tantalum powder during the sintering of the tantalum anode block, thus avoiding the reduction of the specific surface area of the tantalum anode block. We can remove oxides from metal sodium with the metal-ceramic filter or cold trap method.
The process of reduction of potassium and sodium fluoride in an inert atmosphere at 1153 ~ 1173K temperature and the reduction products are metal tantalum powder, potassium fluoride, sodium fluoride, and diluent which are not involved in the reaction.
Before the 1950s, the solid metal sodium and potassium fluorotantalate layer was placed in the reactor of bomb explosion reduction reaction, although the product of tantalum powder is fine particle size, large surface area, oxygen, and carbon content is high, no practical value.
With tantalum capacitors being small and micro, the corresponding need to adopt more surface area tantalum powder, mainly used in the liquid reduction, mainly supplemented by mixing sodium, doping technology, the volume rate of tantalum powder increased to 1000uF – V yield every year.
tantalum-capacitors
The fluoride was removed by dipping, and then washed with HCl18% and HF1% solution at 1 2H for 363K, then washed with pure water and dried at 353K temperature. For the preparation of capacitor grade tantalum powder, tantalum powder should be the original size distribution, vacuum heat treatment (see tantalum powder vacuum heat treatment), crushing and screening and modulation post-processing, if necessary, will also increase the magnesium reduction deoxygenation, pickling, washing and plastic processing, in order to obtain high quality and low and high specific capacitance of capacitor grade tantalum powder.
It is expected that the continuous improvement and development of tantalum powder produced by sodium reduction is the result of the miniaturization, miniaturization, and cost reduction of electronic products. Since the 1960s, the specific capacitance of tantalum powder has been increasing, and the capacitance ratio of tantalum powder has reached 22000～26000uF•V／g in the United States, Japan, Germany, and other countries.
Stanford Advanced Materials supplies high-quality tantalum products to meet our customers’ R&D and production needs. Please visit http://www.samaterials.com for more information.
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