What Should be the Material of the Heating Element to be Used in Vacuum Furnace?

What Should be the Material of the Heating Element to be Used in Vacuum Furnace?

What Is A Vacuum Furnace?

A vacuum furnace is a type of heating equipment with lots of components used in a vacuum surrounding. Generally, it is composed of vacuum vessels, hot zones, pumping systems, cooling systems, and temperature & vacuum control systems. Among them, the hot zone is the heart of a vacuum furnace because it largely affects the process quality, the temperature, the pressure, and the operating cost.

Vacuum Furnace

What Are the Benefits of A Vacuum Furnace?

A reliable vacuum furnace comes with the following advantages.

  • Less Heat Loss: There is no air in the chamber, so there would be less heat loss caused by air convection. Additionally, the temperature in a vacuum furnace is well controlled within the hot zone.
  • Less Contamination: A vacuum furnace features low contamination by carbon, oxygen, and other gases since there is no air inside.
  • High Purity: The pumping systems remove low-temperature by-products, so we could get a higher purity end product.
  • Controlled Process: The process can be computer-controlled.

With these desired properties, vacuum furnaces are used to carry out heating processes such as annealing, sintering, brazing, hardening, and tempering.

Why Choose Molybdenum for Vacuum Furnace?

Molybdenum is used to manufacture vacuum furnace apparatus for the good points below.

  • High Melting Point: Molybdenum has a high melting point of 2,623 °C (4,753 °F). Only tantalum, tungsten, and carbon have higher melting points.
  • High Hardness at Elevated Temperature: Molybdenum is a strong grayish metal with a Mohs hardness of 5.5.
  • Perfect Thermal Properties: Molybdenum metal has high thermal conductivity, a low coefficient of expansion, and remarkable thermal shock resistance.
  • Great Resistance: This refractory metal is highly resistant to corrosion and creeps.
What is Tantalum Tungsten Alloy?

What is Tantalum Tungsten Alloy?

What is Tantalum Tungsten Alloy?

–Tungsten the Element

Tungsten the element (W, 74) is a Block D, Group 6, Period 6 metal element with an atomic weight of 183.84. It was found by Torbern Bergman in 1781. Tungsten has the highest melting point (3420℃) of all the metallic elements, and its density is about 1.7 times that of lead. This element is also famous for its high strength and melting point.

tantalum valuable

–Types of Tantalum Tungsten Alloy

The tantalum tungsten alloys have 3 variants according to their percentage of tungsten added. Ta2.5W, or tantaloy60, has 2.5% tungsten and 0.5% niobium. Ta7.5W, or tantaloy61, has 7.5% tungsten, while Ta10W possesses 10% tungsten and is also called tantaloy63. These alloys have a high melting point of 3005-3030 °C and a large density of 16.7-16.9 g/cm3.

–Tantalum Tungsten Alloy Applications

The application fields of tantalum tungsten alloys lie in the chemical processing industry and heater exchange industry. Similar to pure tantalum, these tantalum tungsten alloys keep useful features such as high melting point, tension resistance, and high corrosion resistance. An oxide layer is formed initially, and it is stable at temperatures below 260°C. This layer could stand strong hot acids like HCl and H2SO4. Because of great thermal conductivity, these alloys are also commonly found to make heat exchangers.

Comparison between Them

Pure tantalum and tantalum tungsten alloys have similarities and disparities in properties and application fields.

As for physical and chemical properties, pure metal and its alloys with tungsten content share some common points. They are strong materials withstanding high temperatures just like pure tantalum. More importantly, they have higher melting points and density, representing their higher strength. Here this article lists the detailed information as follows.

In terms of uses and applications, you can find them both used as chemical reaction pipes and heat changers. However, pure tantalum finds its special applications as capacitors and surgical implants. You’d better take budgets and efficiency into consideration since the tantalum tungsten alloy is a bit more costly but efficient than the pure tantalum.

Pure Tantalum VS. Tantalum Tungsten Alloy

Pure Tantalum VS. Tantalum Tungsten Alloy

What is Tantalum?

–Tantalum the Element

Tantalum the element (Ta, 73) is located in Block D, Group 5, Period 6 in the periodic table, and its atomic weight is 180.94788. This metal element was first discovered by Anders G. Ekeberg in 1802, yet pure tantalum was extracted by Werner von Bolton in 1903. Then, pure tantalum has been mainly mined from columbite-tantalite.

–Tantalum the Metal

Tantalum the metal is a typical refractory metal that is known for its high melting point and corrosion resistance. It looks lustrous gray-blue and has a melting point of 2980℃, which just falls after tungsten and rhenium. The density of pure tantalum is 16.4 g/cm3 and its elastic modulus is 185.7 GPa. All these figures indicate the thermal resistance and high strength of pure tantalum.

–Tantalum Applications

Because of these desirable mechanical and chemical properties, tantalum is applied to make lots of apparatus ranging from capacitors to reaction pipes.

First, nearly 50% to 70% pure tantalum contributes to the manufacturing of capacitors. A majority of capacitors are made from pure tantalum powers or wires. People choose this material because tantalum would form a passive oxide layer with dialectic strength. These capacitors could maintain ideal functions under high temperatures and high voltages. Additionally, tantalum capacitors are employed in the making of switches, mobile phones, fax machines, computers, automobiles, and even defense and military industries.

You can also find pure tantalum in the healthcare and medical field. Thanks to no immune response, the metal material is commonly used to make surgical implants. It can replace skull plates, connects torn nerves, or weaves abdominal muscle.

Pure tantalum could also be applied to make pipes for chemical reactions and heat exchangers for its unique corrosion and heat resistance ability. It can be generally found in the fields of aerospace and metallurgy.

What is Tantalum Tungsten Alloy?

–Tungsten the Element

Tungsten the element (W, 74) is a Block D, Group 6, Period 6 metal element with an atomic weight of 183.84. It was found by Torbern Bergman in 1781. Tungsten has the highest melting point (3420℃) of all the metallic elements, and its density is about 1.7 times that of lead. This element is also famous for its high strength and melting point.

–Types of Tantalum Tungsten Alloy

The tantalum tungsten alloys have 3 variants according to their percentage of tungsten added. Ta2.5W, or tantaloy60, has 2.5% tungsten and 0.5% niobium. Ta7.5W, or tantaloy61, has 7.5% tungsten, while Ta10W possesses 10% tungsten and is also called tantaloy63. These alloys have a high melting point of 3005-3030 °C and a large density of 16.7-16.9 g/cm3.

–Tantalum Tungsten Alloy Applications

The application fields of tantalum tungsten alloys lie in the chemical processing industry and heater exchange industry. Similar to pure tantalum, these tantalum tungsten alloys keep useful features such as high melting point, tension resistance, and high corrosion resistance. An oxide layer is formed on the surface and is stable at temperatures below 260°C. This layer could also stand strong hot acids like HCl and H2SO4. Because of great thermal conductivity, these alloys are also commonly found to make heat exchangers.

Comparison between Them

Pure tantalum and tantalum tungsten alloys have similarities and disparities in properties and application fields.

As for physical and chemical properties, pure tantalum metal and its alloys with tungsten content share some common points. Tantalum tungsten alloys are strong materials withstanding high temperatures just like pure tantalum. More importantly, they have higher melting points and density, representing their higher strength. Detailed information is listed as follows.

Table 1 Comparison between

Pure Tantalum and Tantalum Tungsten Alloy

  Ta W Ta2.5W Ta7.5W Ta10W
Melting Point (°C) 2980 3420 3005 3030 3025
Density (g/cm3) 16.4 19.24 16.7 16.8 16.8
Elastic Modulus (GPa) 185.7 N/A 195 205 200

In terms of uses and applications, you can find them both used as chemical reaction pipes and heat changers. However, pure tantalum finds its special applications as capacitors and surgical implants. You’d better take budgets and efficiency into consideration since the tantalum tungsten alloy is a bit more costly but efficient than the pure tantalum.

Is Tantalum The Same As Niobium?

Is Tantalum The Same As Niobium?

What is tantalum?

Tantalum is a metal element, element symbol is Ta, its atomic number is 73, its density is 16.68g/cm, and its melting point is 2980 DEG C, which is the third most refractory metal. Pure tantalum has a blue color, and excellent ductility, and can be rolled into a very thin plate in the cold state without intermediate annealing.

tantalum

The corrosion resistance of tantalum is the same as that of glass. In the medium temperature (about 150 DEG C), only fluorine, hydrofluoric acid, sulfur trioxide, alkali, and some molten salts have an effect on tantalum. Tantalum is stable at room temperature, it will accelerate oxidation to produce Ta205 if heated to 500 DEG C.

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, has important applications in electronics, metallurgy, the chemical industry, iron and steel, hard alloy, atomic energy, superconducting technology, automotive electronics, aerospace, medical health and scientific research and other high-tech fields.
What is niobium?

What is Niobium?

Niobium is a rare high melting point metal. The melting point is 2467 degrees, the density is 8.6g/cm3, and the lattice type is body-centered cubic. The coefficient of linear expansion (0~100 C) is 7.1 x 10-6. Adding a small amount of niobium into a steel can greatly improve the strength of steel, improve the mechanical and welding properties of steel, and improve its corrosion resistance.

Niobium can be used as a capacitor and niobium-based superalloy. FS – 85 alloy is a structural material for the orbiting engine on the shuttle. C – 103 alloy can be used as a rocket nozzle material. Other niobium alloys, such as Nb – Zr, Nb – Ti, Nb – Ti – Ta, can be used as superconducting materials, and are widely used in magnetic resonance medical human images.

Niobium-based compounds and complexes can be used as catalysts to remove pollution, selective oxidation, and hydrogenation.

Is tantalum the same as niobium?

No. Tantalum and niobium are transition metals that are commonly found together in nature. They have very similar physical and chemical properties. Their properties of hardness, conductivity, and resistance to corrosion largely determine their primary uses today.
The reason for the similarity between niobium and tantalum is the size which is the result of the lanthanide contraction. Thus, the niobium and tantalum have the same size and due to the same size, tantalum and niobium have the same ionic and covalent radii.

Conclusion

Tantalum is chemically much like niobium because both have similar electronic configurations and because the radius of the tantalum ion is nearly the same as that of niobium as a result of the lanthanoid contraction. Niobium is a lustrous, gray, ductile metal with a high melting point, relatively low density, and superconductor properties. Tantalum is a dark blue-gray, dense, ductile, very hard, and easily fabricated metal. It is highly conductive to heat and electricity and renowned for its resistance to acidic corrosion.

Stanford Advanced Materials produce our tantalum products from the metal powder to the finished product. We only use the purest tantalum powder as the source material. This is how we can guarantee you a very high material purity.
We guarantee a purity of 99.95% for our sintered quality tantalum (metallic purity without Nb). The remaining portion is made up primarily of the following elements according to a chemical analysis:

Element Typical max. value
[μg/g]		 Guaranteed max. value
[μg/g]
Fe 17 50
Mo 10 50
Nb 10 100
Ni 5 50
Si 10 50
Ti 1 10
W 20 50
C 11 50
H 2 15
N 5 50
O 81 150
Cd 5 10
Hg – 1
Pb 5 10
Is Tantalum More Strong Than Tungsten?

Is Tantalum More Strong Than Tungsten?

What is tantalum?

Tantalum, a metallic element, is found mainly in tantalite and is symbiotic with niobium. Tantalum is moderately hard, and ductile and can be drawn into thin foil in the form of filaments. Its coefficient of thermal expansion is very small.

Tantalum has excellent chemical properties and is extremely resistant to corrosion. Although tantalum is highly resistant to corrosion, its corrosion resistance is due to the generation of a stable protective film of tantalum pentoxide (Ta2O5) on the surface. It does not react to hydrochloric acid or concentrated nitric acid, either under cold or hot conditions.

It can be used to make evaporating vessels, etc. It can also be used as electrodes for electronic tubes, rectifiers, and electrolytic capacitors. It is also used in medical treatment to make thin sheets or threads to mend damaged tissues.

An Overview of Ta Element

Chemical symbol Ta, gray metal, in the periodic table belongs to the VB group, atomic number 73, atomic weight 180.9479, body-centered cubic crystal, common chemical compound valence +5.

What is tungsten?

Tungsten (W) is one of the so-called transition metals with the atomic number 74. The shiny gray metal is in a solid state at room temperature.

Tungsten is characterized by special physical and chemical properties:
• Heat resistance: After carbon, tungsten has the highest melting point of all elements at 3422°C. It has a boiling point of around 5,700°C. With these properties, the metal can withstand high temperatures and smelting and in addition, has a very low coefficient of thermal expansion
• Density: 19.3 g/cm³; the density of tungsten is almost as high as that of gold in its pure state.
We prepare our tungsten to perform perfectly in its specific applications. We can determine the following properties through the addition of various alloys
• Machinability (such as cutting processes, formability, weldability)
• Microstructure and recrystallization behavior (recrystallization temperature, embrittlement, aging effects)
• Resistance: Tungsten also has high resistance to acids. Even hydrofluoric acid and aqua regia are hardly able to attack tungsten at room temperature
• Physical properties (such as melting point, vapor pressure, density, electrical conductivity, thermal conductivity, thermal expansion, heat capacity, and electron work function)
• Mechanical properties (such as strength, fracture behavior, creep resistance, and ductility)
• Chemical properties (corrosion resistance)

Is tantalum more strong than tungsten?

Tantalum is highly resistant to scratches and breakage and is extremely durable. Tantalum is therefore resistant to corrosion, and only if exposed to hydrofluoric acid it can corrode.

Unlike metals, such as tungsten, it is also shatterproof. This makes it great for individuals who lead active lives with busy hands.

Choose the Right Tantalum Foil for your Application

Choose the Right Tantalum Foil for your Application

If you need a metal foil that can withstand high temperatures and has extremely strong chemical resistance to most corrosive environments then tantalum foil is already on your short list of materials.

ta metal foil

Tantalum belongs to a class of metals known as refractory metals, which are defined by their strong resistance to heat and wear. It has a melting point of 5,463 °F (2,996 °C), the fourth highest of all metals.

Like most metals, tantalum forms a thin but dense protective oxide layer (Ta2O5) when exposed to the atmosphere. This oxide layer firmly adheres to the surface of the metal, acting as a barrier that protects the underlying metal from further corrosion.

tantalum foil

Below are some examples of common applications for tantalum foils.

Included with each application are some suggestions based on how others in that industry specify the tantalum foils for such uses.  If your application is not on the list, we suggest contacting Stanford Advanced Materials’ technical sales at sales@samaterials.com.

 

Tantalum foils for Machined fasteners 

Tantalum fasteners are made of alternative materials prone to failure or that require expensive equipment shutdowns for maintenance. Tantalum foils appear in industries such as mining, energy, and pharmaceuticals as well as in metal and chemical processing.  For customers who prefer to make their own fasteners unannealed tantalum rod is most commonly requested.  Annealed tantalum foils are sometimes difficult to machine because the metal has a tendency to gum.  Unannealed tantalum foils make machining and threading easier.  As a service to our customers, Stanford Advanced Materials also offers machined fasteners to your custom sizes.

Tantalum foils for Vacuum furnace heating elements 

Because of tantalum’s oxidation resistance and high melting point, many vacuum furnace components incorporate tantalum foils. Grain-stabilized tantalum rod is designed to survive longer in high-temperature environments by reducing grain growth.  Stanford Advanced Materials can grain stabilize tantalum foils by producing the product using a powder metallurgy process which creates a very uniform and fine grain size or as an alternative the rods can be produced with very small amounts of additives such a Yttrium.  Either method prolongs or prevents the tantalum grains from growing and therefore increases machine life expectancy due to its ability to withstand high temperatures for long periods of time.

Tantalum foils for Machined parts for chemical processing equipment 

Tantalum foils have corrosion-resistant properties which make it a choice material for machined parts used in chemical processing equipment. Tantalum machined parts replace inferior materials that do not perform as well in harsh chemical environments and require extensive maintenance.  In most cases customer request tantalum 2.5% tungsten foil which has slightly more strength and corrosion resistance.  When ordering tantalum rods for such applications we suggest you order ASTM B365 R05200 for pure tantalum rods or ASTM B365 R05252 for tantalum 2.5% tungsten foils.

Tantalum foils for X-ray/radiation shielding

Due to its high density, tantalum’s radio-opaque qualities make it ideal for X-ray and shielding applications seeking to prevent radiation leakage. Tantalum foils are often manufactured into shielding which protects sensitive electronic components in aerospace structures as well as components operating in corrosive environments.  There is great variability in the tantalum foils used in applications such as this.  Because the shielding is due to tantalum’s density, which is intrinsic, just about any grade of tantalum foil will be functional.

Tantalum foils for Sputtering Targets for Gun Barrels

Tantalum foils are sometimes used as a sputtering target to coat the inside of gun barrels with tantalum as a replacement for chromium.  This makes the gun barrel manufacturing process more environmentally friendly and lets manufacturers reduce their ecological impact.  When purchasing tantalum for such an application most customers prefer tantalum foils that are fully annealed, melted in an electron beam furnace (ASTM B365 R05200), and have a 99.95% minimum purity.  Some customers have specified tantalum 2.5% tungsten or tantalum 10% tungsten foils.

 

Is Tantalum Worth More Than Gold?

Is Tantalum Worth More Than Gold?

Why is tantalum so valuable?

The most valuable of metal worth materials is not gold or platinum like you might expect, but a metal you’ve possibly never heard of: tantalum.

There’s a good reason for this.

tantalum

The rarest stable element- Tantalum

As you know, Tantalum is the rarest stable element in our entire solar system, with just one atom of tantalum for every 181 billion atoms of other elements.

Tantalum is a lithophile element with chalcophile affinities. Tantalum is almost exclusively found in complex oxide and hydroxide minerals, with the exception of the borate mineral behierite and the only known non-oxide, tantalum carbide TaC.

Common Ta minerals include tantalite (Fe,Mn)(Ta,Nb)2O6, formanite YTaO4, and mikrolithe. Tantalum is nearly always found in association with Nb. The most common host minerals for Ta in igneous rock types include pyroxene, amphibole, biotite, ilmenite, and sphene.

Excellent characteristics- Tantalum

Tantalum has a series of excellent characteristics such as a high melting point, low vapor pressure, good cold processing performance, high chemical stability, strong resistance to liquid metal and acid and alkali corrosion, and large dielectric constant of the surface oxide film, which makes it an important modern functional material.

Extremely good corrosion resistance – Tantalum

Tantalum rapidly generates a surface oxide film that closely covers its metallic substrate in almost any environment, which is extremely thin and dense, impervious to almost all media, and self-healing once damaged. Thanks to this excellent protective film, tantalum has extremely good corrosion resistance. Except for fluorine, hydrofluoric acid, acidic solutions containing fluorine ions, fuming nitric acid, and strong alkalis, tantalum is impervious to corrosion in most media.

Wide Applications – Tantalum

With its combination of specific physical and chemical properties, tantalum is an important product in many applications:

tantalum applications
Tantalum features a high degree of biocompatibility. For this reason, it is used in medical technology as a radiographic contrast agent and in the production of bone replacement material and implants.
• In the aerospace and energy industries, tantalum increases the corrosion resistance of alloys in turbine blades.
• Tantalum’s chemical corrosion and high-temperature resistance properties provide many benefits to the chemical process industry. For this reason, tantalum is used in the production of reactor coatings, heat exchangers, and pipelines
• Its ability to form an extremely thin oxide coating which provides a protection layer, makes tantalum the material of choice in the production of small, high-quality capacitors

In conclusion

We use our “unyielding” material – Tantalum, for example, tantalum foil, and tantalum powder, are used to produce heat exchangers for the equipment construction sector, charge carriers for furnace construction, implants for medical technology, and capacitor components for the electronics industry.

What are Common Uses of Tantalum?

What are Common Uses of Tantalum?

Tantalum has excellent chemical properties and is extremely resistant to corrosion. It does not react to hydrochloric acid, concentrated nitric acid, or “aqua regia” under either cold or hot conditions. When tantalum is immersed in sulfuric acid at 200°C for one year, the surface layer is only damaged by 0.006 mm.

tantalum

Tungsten plate, molybdenum plate, tungsten rod, molybdenum rod, tungsten tube, molybdenum tube, tungsten crucible, molybdenum crucible experiments have proved that tantalum rod does not react to an alkaline solution, chlorine gas, bromine water, dilute sulfuric acid and many other agents under normal conditions, but only reacts to hydrofluoric acid and hot concentrated sulfuric acid. This is a relatively rare occurrence among metals.

The properties of tantalum make it suitable for a wide range of applications. In equipment for the production of various inorganic acids, tantalum can be used as a replacement for stainless steel, and its life can be increased by dozens of times compared to stainless steel. In addition, in the chemical, electronic and electrical industries, tantalum can replace the tasks that used to be undertaken by the precious metal platinum, making the costs required much lower.

In addition, tantalum is also an important element in the refining of super-strength steel, corrosion-resistant steel, and heat-resistant steel alloys, and can provide special materials necessary for the development of rockets, spacecraft, jet aircraft, and other space technologies.

Non-magnetic alloys made of tantalum and tungsten are widely used in the electrical industry, especially tantalum carbide composed of tantalum and carbon, which has great hardness, even under high conditions, and gold steel stone is not comparable.

Tungsten plate, molybdenum plate, tungsten rod, molybdenum rod, tungsten tube, molybdenum tube, tungsten crucible, molybdenum crucible made of it can cut many hard alloys at high speed; all kinds of drill bits made of it can replace the hardest alloy or gold steel stone. Therefore, tantalum is also considered to be the “vitamin” in smelting.

What are 8 Uses for Tantalum?

What are 8 Uses for Tantalum?

Niobium vs. Tantalum

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

ta powder

Chemical properties of tantalum

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

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

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

Tantalum uses and applications

  1. Electronic industry:

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

  1. Steel industry:

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

  1. Atomic energy industry:

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

  1. Petroleum and chemical industries:

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

  1. aerospace air industry:

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

  1. Cemented carbide:

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

  1. Superconducting materials:

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

  1. Medical field:

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

Does Tantalum Have a High Resistance to Corrosion?

Does Tantalum Have a High Resistance to Corrosion?

Corrosion Resistance of Tantalum

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

tantalum corrosion resistance

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

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

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

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

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

The performance of tantalum capacitors

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

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

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

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

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