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.
Tantalum is a sensible choice whenever high corrosion resistance is required. This platinum-gray-colored metal has a density of 16.6 g/cm3 which is twice as dense as steel. With its combination of specific physical and chemical properties, tantalum is an important product in many applications. Do you know how tantalum is made?
Tantalum smelting process
Tantalum niobium ore is the main raw material for the production of tantalum, but it is often associated with a variety of metals, so the main step is the decomposition of tantalum smelting concentrates, purification, and separation of tantalum and niobium, producing the pure compound of tantalum and niobium, finally, we can produce metal.
To achieve ore–decomposition, we can use the hydrofluoric acid decomposition method, sodium hydroxide melting method, and chlorination. The method can be used in the separation of tantalum and niobium by solvent extraction, fractional crystallization, and ion exchange method.
Preparation of tantalum
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 a 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.
Sodium thermal reduction process
Sodium metal thermal reduction method is an important method for the production of tantalum powder, is the main method of industrial production of tantalum powder (including metallurgical Ta powder), the metal tantalum powder particle shape is complex, large surface area, suitable for anode material for tantalum electrolytic capacitors, by electron beam melting, vacuum arc melting of tantalum or tantalum sintered in vacuum refining, made of high purity tantalum ingot or rod, and then processed into a variety of tantalum.
In order to obtain high purity tantalum powder, in addition to the main raw material, sodium and potassium fluorotantalate diluent (or NaCl+KCI), sodium chloride (argon or helium) must reach the required purity, must also be dehydration treated strictly at different temperatures in advance. It is also necessary to carry out the vacuum heat treatment at the temperature of 598 ~ 648K. After vacuum heat treatment, potassium fluorotantalate can remove the residual organic matter and hydrogen fluoride, and become the potassium fluorotantalate grain refinement, obtaining fine tantalum powder in reduction.
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.
In this way, the reaction period is too long, the product size is coarse, and can only be used as 3000/uF.V/g low volume tantalum powder. After improvement by liquid-solid mixed loading reaction of sodium-based reduction, the production cycle is shortened 3/4 than gas-liquid reaction, tantalum powder volume increased by more than 30%, but still not ideal will be phased out.
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.
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.
The powdered tantalum is dark gray or silver-gray, which is an important raw material for the preparation of capacitors and tantalum materials.
The quality of capacitor grade tantalum powder used for manufacturing tantalum capacitor cores is mainly measured by its physical properties, chemical composition, and electrical properties.
Physical Properties
Physical properties mainly include average particle size, particle shape, fluidity and forming density. Low-pressure series products should have a small average particle size, complex grain shape, and low forming density, while high-pressure series products should have a large average particle size, simple grain shape, and high forming density. The fluidity determines whether tantalum powder can be formed by an automatic forming machine. Therefore, with the rapid increase in the production of small chip tantalum capacitors, great attention has been paid to the fluidity of tantalum powder.
Chemical Composition
The chemical composition has a direct effect on the electrical properties of tantalum powder. High impurity content, especially high content of phosphorus, boron, oxygen, carbon, potassium, sodium, and iron, will increase the leakage current and decrease the breakdown voltage of tantalum anodized film, so as to degrade the electrical properties of tantalum powder. However, the content of certain elements in tantalum powder is not as low as possible. It is found that adding certain selected elements can improve certain electrical properties of tantalum powder, and it has been proved that adding a small amount of phosphide to tantalum powder can inhibit the shrinkage of tantalum during sintering and thus increase the capacitance of tantalum powder by weight, while the breakdown voltage of tantalum powder can be increased by adding trace aluminum compounds with high dielectric strength.
Electrical properties
Electrical properties refer to the dc leakage current, breakdown voltage, and capacitance of the oxide film on the surface of tantalum anode after weighing, pressing, vacuum sintering, and anodizing of tantalum powder. All these properties are not only determined by the intrinsic characteristics of amorphous tantalum pentoxide anodized film but are also closely related to the physical properties and chemical composition of tantalum powder.
As a new manufacturing method for the global manufacturing industry, additive manufacturing caught the attention of the public six or seven years ago. And “3D printing”, a very down-to-earth and vivid name, was coined. Metal 3D printing is widely regarded as the most promising technology. Tantalum powder is an excellent biocompatible material, which has very strong biological inertia and corrosion resistance. Stanford Advanced Materials (SAM) has begun research on the application of 3D printing of tantalum powder in biomedicines such as hip joints.
Tantalum has a high boiling point, excellent resistance to corrosion, low coefficient of thermal expansion, and a high coefficient of capacitance, which has been used in electronic industries. SAM’s spherical tantalum powder is a good choice for 3d printing tech as it has high purity, uniform particle size, complete surface structure, easy dispersion, large specific surface area, and high surface activity.
SAM has successfully produced a biologically inert tantalum lattice structure and can have specific and random results. These structures follow the structural rigidity of human bones and can be well combined with bone cells so that the human body can excellently accept this kind of new tissue. SAM is dedicated to providing ultra-fine tantalum powder (D50=3um, D90<10um) for bio-applications. When used for additive manufacturing and selective laser melting, this type of ultra-fine tantalum powder can always maintain structural consistency. The final surface can also be further modified. The metal properties are still very stable.
SAM has successfully produced a biologically inert tantalum lattice structure and can have specific and random results. These structures follow the structural rigidity of human bones and can be well combined with bone cells so that the human body can excellently accept this kind of new tissue. SAM is dedicated to providing ultra-fine tantalum powder for bio-applications. When used for additive manufacturing and selective laser melting, this type of ultra-fine tantalum powder can always maintain structural consistency. The final surface can also be further modified. The metal properties are still very stable.
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.
With the advent of the era of big data, the storage of big data has become a matter of concern. Tantalum materials are developing at an amazing speed in today’s rapid development of the electronics industry.
Tantalum capacitors
Tantalum capacitors are one the indispensable electronic components for radar, aerospace aircraft, and missiles, and are widely used in civil applications, such as mobile communication, electronic equipment, instruments, and other aspects. On the contrary, the development of the electronic industry requires more and more stringent miniaturization and high reliability of tantalum capacitors.
Tantalum capacitors
Capacitor grade tantalum wire
Capacitor grade tantalum wire is used to make anode lead of tantalum electrolytic capacitor, and its advantages are high permittivity of the oxide film and high reliability. Compared with metallurgical tantalum wire, capacitor grade tantalum wire has high chemical purity, good surface finish, and anti-oxygen brittleness. Using tantalum powder as raw material, capacitor tantalum wire is made by powder metallurgy method after forming tantalum bar, and then through rolling, drawing, and other metal plastic processing. As a result, its surface is smooth and clean, and no grooves, burrs or other defects.
Capacitor grade tantalum wire
The important performance indexes of capacitor-grade tantalum wire include tensile strength, linearity, chemical composition, leakage current, etc. The diameter of the capacitor-grade tantalum is generally between Φ0.15 mm to Φ1.0 mm, and the tensile strength is between 400mpa and 1700mpa.
Tantalum target
The purity of the tantalum target is 99.95%, the surface is smooth, the grain diameter is less than 100μm, and the grain texture is mainly [111] type texture. Because of its high conductivity, high thermal stability, and barrier to foreign atoms, tantalum can be used as a barrier layer to prevent copper from diffusing into silicon. As electrode materials and surface engineering materials, tantalum target has been widely used in liquid crystal display (LCD) and heat-resistant, corrosion-resistant, and highly conductive coating industries.
Tantalum target
Tantalum sputtering target material has become a key raw material in the semiconductor industry, which is irreplaceable and has a broad application prospect. The tantalum sputtering target is completed by physical vapor deposition. The specific process includes high-pressure accelerated gaseous ions bombarding the tantalum target surface, enabling the atoms on the target surface to get enough energy and break free, sputtering on the silicon chip, and finally forming the precise wiring structure in the semiconductor chip with photolithography, corrosion, and other processes. Tantalum material can be used for various thin-film applications, as diffusion barrier material applied to memory devices, such as gate electrodes of MOSFET devices and protective coating on printing head devices.
The function of capacitors is to remove the crosstalk of various high-frequency signals generated by the chip itself to other chips so that each chip module can work normally without interference. In the high frequency electronic oscillating circuit, the SMT capacitance and crystal oscillator together form an oscillating circuit to provide the required clock frequency. Its main chemical components are nickel and chromium, and the shape is filamentous, so it is called nickel-chromium wire.
Ceramic capacitors
Ceramic capacitors are made by high dielectric constant capacitor ceramics, which are extruded into tubes, wafers, or disks as the medium. It is divided into two types: high-frequency porcelain medium and low-frequency porcelain medium. Low-frequency ceramic dielectric vessels are limited to those occasions where they are used as by-passes or dc insulation in circuits with lower operating frequencies, or where stability and loss requirements are not high. Such capacitors are not suitable for use in pulse circuits because they are vulnerable to breakdown by impulse voltage.
Tantalum Capacitors
Tantalum capacitors are characterized by long life, high-temperature resistance, high accuracy and excellent performance of the high-frequency filter. Tantalum capacitors can generally withstand high temperature and voltage and are often used for high-frequency filtering. Ceramic capacitors look a bit like patch resistors, but they are smaller in capacity and more expensive than aluminum capacitors and have relatively low voltage and current resistance.
Compared with ceramic capacitors, tantalum capacitors on SMT are labeled with capacitance and pressure resistance, and the surface color is usually yellow and black. SMT aluminum electrolytic capacitors have a larger capacity than SMT tantalum capacitors, which is more commonly seen on the display card, with a capacity between 300 VPS F and 1,500 VPS F.
Tantalum Capacitors
The difference between tantalum capacitors and ceramic capacitors
They are made of different materials. As the name implies, tantalum capacitors use tantalum as the medium, while ceramic capacitors use ceramics as the medium. The capacitance of ceramic capacitors is much smaller than that of tantalum capacitors. Tantalum electrolytic capacitors can achieve a small capacitance, while the ceramic capacitor can hardly achieve the ideal performance when the capacitance is large.
Tantalum capacitors and ceramic capacitors also have different uses. Tantalum capacitors can be used as coupling, and the frequency range of such circuits as filter oscillatory bypass is large, while ceramic capacitors are mostly used in high-frequency circuits. Since tantalum capacitors are mainly made of tantalum, a very rare metal, so the capacitor grade tantalum powder is very expensive, while tantalum capacitors are sold at a high price and generally used only in high-end products that are not price-sensitive.
Multilayer ceramic capacitors are now the most widely used in almost all electronic products. In recent years, the capacity of ceramic capacitors has become larger and larger with the continuous progress of technology, and 47UF multi-layer ceramic capacitors have emerged. However, the large-capacity ceramic capacitors can only be made by a few big Japanese brands, so the price is still more expensive, which is similar to the price of tantalum capacitors.
Tantalum metal mainly exists in tantalite ore and is symbiotic with niobium. Tantalum is of moderate hardness and ductility and can be drawn into tantalum wire or tantalum foil. Tantalum has a wide range of applications due to its characteristics， and it widely exists in tantalite, tantalum alloy, tantalum powder, tantalum capacitors, etc.
Tantalum alloy is an alloy based on tantalum adding other elements. The tantalum anode oxide film is stable and corrosion-resistant. It has excellent dielectric properties and is suitable for making the electrolytic capacitor. Tantalum is highly resistant to chemical corrosion. Except for hydrogen fluoride, sulfur trioxide, hydrofluoric acid, hot concentrated sulfuric acid and alkali, tantalum can resist the corrosion of all organic and inorganic acids. Therefore, it can be used as corrosion resistant materials for chemical industry and medicine.
As tantalum is similar to some rare elements such as uranium, thorium, rare earth, titanium, zirconium, tungsten, and common elements tin, calcium, iron, and manganese in crystalline chemistry, it is easy to have equivalence and heteromorphism.
The compact oxide film formed on the surface of metallic tantalum has the properties of valve metal of unidirectional conduction. The anodic film made of tantalum powder has chemical stability (especially in acidic electrolyte stability), high resistivity (7.5 x 1010 Ω, cm), dielectric constant (27.6) and small leakage current. Tantalum is not only the raw material for the production of pure metal tantalum but also used in the electronics industry. Lithium tantalate monocrystals and special optical glass with high refraction and low dispersion can be used as a catalyst in the chemical industry.
Tantalum oxide is a white powder insoluble in water and acids, but soluble in molten potassium bisulfate and hydrofluoric acid. The minerals containing tantalum and niobium are mainly iron tantalum and calcined greenstone. The ones containing more tantalum are called tantalite, while the ones containing more niobium are called niobite.
The design of tantalum capacitors requires that the product performance parameters of tantalum capacitors can meet the circuit signal characteristics. However, it is often impossible to guarantee that the above two tasks are done well. Therefore, it is inevitable that failures of one kind or another will occur in the process of use. The solid tantalum capacitors were first developed in 1956 by Bell Laboratories in the United States. Tantalum capacitors can easily obtain large capacity, and there are few competitors in power filter, ac bypass, and other applications.
Rare metal material technology is one of the most important subjects in the field of material science and engineering in the new century, as well as a key material for the development of high and new technology, and tantalum and niobium play an important role in this field. The development of modern high technology such as information technology, new energy technology, space technology, biotechnology, and superconductivity is closely related to rare metal materials, especially tantalum and niobium.
Main products and performance
At present, the main products used in the tantalum-niobium industry include tantalum powder, tantalum wire, tantalum carbide, tantalum, and its alloy ingots, tantalum and its alloy processing materials, tantalum target materials, tantalum oxide, lithium tantalite; niobium powder, niobium rod, niobium foil, and its alloy ingots, niobium and its alloy additives, niobium oxide, niobium tube, lithium niobate, niobium, and its alloy superconducting materials, etc.
Tantalum powder and tantalum wire are the key materials for making tantalum capacitors, which are widely used in mobile phones, computers, digital products, automobiles, aerospace electronics, and other fields. About 60 percent of the world’s tantalum is used to make tantalum capacitors.
Tantalum and niobium target materials are used in semiconductor devices and liquid crystal display technologies, and niobium oxide, niobium powder, and niobium wire are used in making ceramic and niobium capacitors. About 90% of the world’s niobium is used in the steel industry, and niobium wire is mainly used in the production of high-strength low-alloy steel, stainless steel, heat-resistant steel, clearance steel, carbon steel, tool steel, rail steel, casting steel.
Superalloys can be produced by adding tantalum or niobium to tungsten, molybdenum, nickel, cobalt, vanadium, ferroalloys, or by using tantalum and niobium as bases, which are important structural materials for aerospace engines, ground-based air turbine engines, modern weapons, and harsh industrial environment facilities.
Because of the good superconductivity of niobium and tantalum metal, the addition of niobium and tantalum into the materials used to make wires and cables can greatly reduce the loss of power and thus save power. Tantalum and niobium are excellent materials for acid and liquid metal corrosion resistance, so they can be used in the chemical industry for digesters, heaters, coolers, and various device containers. Besides that, tantalum and niobium metals and their alloys can also be used as reactor shell materials and high-energy physics superconducting devices.
Industry’s outlook
With the development of high and new technology in the world, such as electronics, metallurgy, aerospace, and aviation, the international market demands for the smelting and processing of rare metals such as tantalum powder and tantalum wire, tantalum niobium crystal materials and niobium alloy are increasing day by day. Currently, major tantalum and niobium metal smelters and processing industries around the world are carrying out global economic integration, and actively exploring the market to improve the market share.
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