What is the Trend of Ta & Nb Market?

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.

ta trend

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.

Processing Technology of Tantalum Bar to Wire

The production of tantalum wire is usually carried out by powder metallurgy or another isostatic pressing, vacuum sintering to obtain a tantalum rod, followed by cold rolling and surface cleaning to obtain a tantalum strip, and then the wire is obtained by surface oxidation coating, stretching, pickling, water washing, and annealing. The processing process of the tantalum bar to wire includes the following steps.

tantalum wire

Isostatic molding

The chemical composition of the tantalum powder raw material for preparing the tantalum should meet the specified requirements, and the particle size distribution should satisfy the requirement that 100% is less than 0.074 m, and the content of less than 0.038 m (400) is not less than 60%. The bar blank after press forming requires no defects on the surface, no cracks, and has a certain strength, reaching 70% of the theoretical density.

Vacuum sintering

Usually, the melt sintering is performed, the sintering vacuum should be less than 0.133Pa, and the highest sintering temperature should be controlled within 2600 °C. Generally, after two times of vertical melting and sintering, the relative density of the tantalum can reach about 98%, and the surface of the tantalum is required to be smooth, without cracks, melted tumor knots, and bubbling.

Cold rolling

The production of tantalum wire and the forging of tantalum bars are generally carried out by cold rolling. It can be used as a manufacturing process before die forging, or it can be directly rolled into an ingot. Roll forging is a process in which a tantalum rod is passed through a pair of rotating wrought rolls equipped with circular arc dies, and plastically deformed by means of a cavity to obtain the desired ingot.

Anodizing

The purpose of anodizing is to uniformly coat an oxide film on the surface of the tantalum ingot (wire). As a carrier of the lubricant, the oxide film can uniformly and firmly adhere the lubricant, which can reduce the tensile friction coefficient, ensure the surface quality of the silk, and cannot directly contact the metal and the mold, then prevent the bonding and improve the tensile performance.

The standard of the oxide film is that the adhesion is strong, the micro-tightness is firm, the color is not easy to fall off, the thickness is uniform, the insulation is good, the residual current is small, and the surface is less crystalline.

Stretching

Stretching is a major process in the production of tantalum wire. The choice of lubricant, drawing die, stretching pass, and stretching speed will directly affect the quality of the wire. The stretching of tantalum is divided into thick wire and fine wire. Solid wax is generally used as a lubricant for roughening the thick tantalum wire with an oxide film, and an aqueous solution of grease soap is generally used as a lubricant when the tantalum wire with oxide film is finely drawn. The tensile die has cemented carbide and diamond, the latter is better but more expensive. The processing rate of the stretching pass depends mainly on the quality of the oxide film and the quality of the lubricant.

The surface of the wire after stretching is stuck with oil and residual oxide film, so it is necessary to clean the surface with acid and then with pure water. For the fine wire, the acidity of the pickling and the pickling time is strictly controlled. When the oxygen content and the surface brightness are good, the acidity and pickling time should be minimized.

Vacuum annealing

Annealing of the tantalum wire includes two parts, intermediate annealing and finished annealing. The purpose of intermediate annealing is to eliminate work hardening and improve the processing plasticity of the wire to continue stretching, while annealing is to achieve the desired properties of the finished product.

Tantalum has good plasticity at room temperature, and the work hardening tendency at room temperature is not large. The practice has shown that the billet produced by powder metallurgy can be processed until the total deformation rate is about 95%; the total deformation rate of the extruded billet by electron beam melting and consumable arc melting can reach more than 99%. After the recrystallization annealing, the plasticity of tantalum at room temperature is completely recovered.

Wire rewinding

In order to facilitate the material leaving the factory after the wire has been annealed, it is generally necessary to rewind on a certain winding machine. When rewinding, it is necessary to prevent the surface from being stained or scratched and to prevent twisting.

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.

How is Tantalum Used in the Military Industry?

The inner covering of the gun body

When gunpowder is exploded, it produces a tail flame with a temperature of 2500 ~ 3500K and a pressure of 300 ~ 800MPa. The tail flame contains such corrosive components as H2S, CO, O2, H2, H2O, N2, and powder residue particles. Therefore, the gun barrel will undergo the physical and chemical effects of high-temperature and high-pressure gunpowder gas (the thermal effect of high-temperature gas, the scouring of high-speed airflow, the corrosion of gunpowder gas residue in the bore, and the wear of high-speed moving projectile on the inner wall) when the projectile is launched. Under this working condition, the gun barrel bore will be subjected to severe ablative erosion and wear, which will lead to the change in the geometry and size of the barrel bore, which will directly affect the firing accuracy of the gun and the life of the barrel.

military industry

Therefore, the research on ablative behavior and protection of gun barrels has received extensive attention. The main considerations of gun barrel material are thermal properties, including heat resistance, thermal expansion, thermal conductivity, and thermal shock resistance; mechanical properties, including elastic modulus, mechanical strength, and hardness; chemical stability, that is, the chemical stability of materials in high temperature and corrosive atmosphere.

Tantalum (Ta) has good physical and chemical properties. It is a high melting point (2996℃) refractory metal, with low thermal conductivity (57W/m℃), good chemical corrosion resistance (acid, salt, and organic chemical corrosion resistance at high temperature), and excellent ablative resistance, as well as good plastic and toughness. Tantalum or tantalum alloy coating is considered to be an ideal coating system to replace the electroplating Cr coating for ablative and scour resistance. If the tantalum layer is to be used in the gun barrel for the purpose of gas ablation of fire retardant for a long time, the sputtering Ta layer should be mainly composed of alpha-ta with a thickness of at least 75 microns. The coating should have enough binding force with the substrate in all directions to resist the thermal shock and high shear stress in the gun firing process.

The cylindrical magnetron sputtering tantalum technology was proposed by Benet Laboratories of the United States army for the dimension characteristics of the gun barrel; Also, the trial production of cylindrical magnetron sputtering deposition technology platform for 120mm, 155mm, and 105mm sputtering full-length large-caliber gun tubes were built in Waterfleet Arsenal, which was used for the magnetron sputtering full-bore tantalum plating for Abrams, Crusader, and future combat systems.

In the Bennett experiment of the US army, Vigilante et al. prepared pure tantalum ablative resistant layer in a 25mm rifled gun barrel and 120mm smooth rifled gun barrel bore by using explosive spraying technology. It was found that the bonding between the tantalum layer and the base metal was good, but the adiabatic shear band would appear in the base steel of the body tube and a Ta-Fe brittle intermetallic compound phase would be formed.

Armor-piercing projectile

In the 1980s, a new type of warhead, the explosively formed penetrator, was successfully developed, mainly using tantalum on the butterfly bushing next to the high explosive. When the explosive is detonated, the butterfly disc morphs into a long, steady, sliver of a penetrator, accelerating towards its target.

With the development of armor materials, modern anti-armor warhead has higher and higher requirements on the materials of explosive forming munition type hood. The formation of a longer and more stable jet requires high density, high sound velocity, good thermal conductivity, and high dynamic fracture elongation. In addition, it is required that the material has a fine grain, low recrystallization temperature, certain texture, and other microstructure.

Tantalum and depleted uranium have high density, high dynamic elongation, and arson. Especially, tantalum has a high density (16.6g/cm3) and good dynamic characteristics, which is a kind of material mainly used in the research of explosive forming ammunition types. As a material of explosively formed munitions, tantalum is widely used in TOW-2B, TOW-NG, and other U.S. missiles. Ballistic experiments show that tantalum’s affinity is 30%~35% higher than that of copper, and can reach 150mm.

At present, the research on using tantalum as the coating material mainly focuses on improving the processing technology and saving the cost. Among them, the United States Army Equipment Research and Development Center (ARDEC) uses the P/M method to develop explosively formed tantalum cartridge type housing; Two kinds of tantalum powders, PM2 and PM4, are pressed by static pressure, sintered, extruded, and processed into blank material, and then annealed and forged by rotary forging, tantalum cartridge prepared in this way can be successfully applied to a well-shaped explosive forming projectile; German Smart-155mm end-sensitive projectile is one of the most advanced end-sensitive projectiles in the world today. The missile is made of a thin-wall structure, and its sensitive device has high anti-interference ability, which can work normally in fog or a bad environment; The BONUS-155mm dexterous shell, jointly developed by the Swedish Bofors Company and the ground weapon group, has been mass-produced and is suitable for 45-caliber artillery.

High purity materials are required for the electrochemical cover of explosive forming. Trace elements have a great influence on the physical properties of the cover material, and ultimately affect the penetration depth of the projectile. The purity of tantalum has an influence on the strength, crystal structure, and length of the explosive forming projectile (EFP). Therefore, the purity of tantalum shall be strictly controlled in the preparation process.

Ultra-high vacuum aspirating material

Ultra-high vacuum aspirating material (tantalum alloy) is used in night vision equipment in conventional defense weapons. Using 15% tantalum as the framework and titanium as the adsorbent of hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, water vapor, methane, neon, and other gases can improve the service life of the inspiratory material. This material can be applied to the infrared camera tube in the active infrared night-vision instrument and the low-light tube in the passive low-light night vision instrument, to ensure the long-term high vacuum in the vacuum tube, so as to achieve the high efficiency, high-life span and improve the definition of the night vision instrument.

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.

Is tantalum Toxic?

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.

solid tantalum chip capacitors

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.

How is the Tantalum Made?

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

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.

Please visit http://www.samaterials.com for more information.

Factors Affecting the Quality of Capacitor Grade Tantalum Powder

The powdered tantalum is dark gray or silver-gray, which is an important raw material for the preparation of capacitors and tantalum materials.

tantalum powder

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.

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How is the 3D Printing Tantalum Powder used in Biomedicine?

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.

medical ortho

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.

Please visit http://www.samaterials.com for more information.

What Are the Advantages of Tantalum Electrolytic Capacitors

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 capacitors

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
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%.

capacitor-tantalum

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.

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How is Tantalum Metal Used in Various Industries Made?

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 powder

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
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
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.

Tantalum Processing Materials used in the Electronics Industry

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 target

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
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
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 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.

Please visit http://www.samaterials.com for more information.