March 2023 – Magic Metal Tantalum

Niobium-based Photoactive Water Splitting Catalyst

Niobium-based photoactive semiconductors have been extensively used as water-splitting catalysts because of the following features.

Desirable bandgap: The photo-catalyst must have the desirable bandgap that allows oxidation and reduction reactions to happen. Namely, the catalyst should have a minimum bandgap of 1.23eV so that H2O would change into O2 and H+ would transform into H2.
Positive conduction band: The valence band and conduction band matter. The more positive the conduction band is, the higher the reduction potential the catalyst has. For instance, niobates possess a more positive position of conduction bands compared with tantalates, so they have higher reduction potentials for redox reactions.
Special structures: Niobium-based semiconductors have special structures, so they have better photocatalytic performance. Niobium compounds have different structures due to their crystallization. For instance, the symmetry of NbO4-tetrahedral and NbO6-octahedral units could be easily tailored, and Nb5+ has a large affinity to oxygen.
Various types: Nb-based materials can be categorized into three types. Niobium pentoxide stands out for its electronic and morphological properties. Niobium-layered compounds are promising photo-catalysts with a 2D layered arrangement and a large surface area. You can add niobium as a dopant agent to improve the reaction efficiency as well.

Other Uses of Niobium

Niobium is a grey ductile metal with a range of applications.

About 90% of niobium is used to manufacture high-end steel. Adding a small amount of niobium to the steel could increase the strength, toughness, and corrosion resistance of steel. The weldability and formability could also be improved.

Niobium is commonly applied to make superconducting materials as well. The well-known Apollo Service Module, the Large Hadron Collider, and the International Thermonuclear Experimental Reactor employed numerous superconductors.

Related reading: 10 Important Uses Of Niobium

Conclusion

A variety of niobium-based photoactive semiconductors are used as catalysts to enhance the performance of artificial photosynthesis and solar water splitting because of their chemical and structural properties. Advanced Refractory Metals (ARM) is a leading supplier of niobium and its alloys. For more information, please check our homepage.

Titanium Fastener VS. Stainless Steel Fastener

Let’s begin with some basic information.

As a tough and corrosion-resistant alloy, stainless steel has been used since the 20^th century. It is composed of about 10.5% chrome and a variety of other elements, which include aluminum, carbon, nickel, molybdenum, nitrogen, sulfur, silicon, titanium, copper, and niobium. The chromium content contributes to its rust-resistance and heat-resistance features. Thanks to all these desirable properties, stainless steel fasteners and other stainless steel parts are widely employed in the construction, automotive, and medical industries.

Titanium is a light yet tough metal. Titanium fasteners have a low density of 4.5 g/cm3 and a high strength-to-weight ratio. The melting point of titanium is over 1650 °C and the boiling point is 3287 °C. So, the lustrous silvery metal is perfect for chemical appliances, aircraft skeletons, marine apparatus, and medical equipment.

Stainless Steel VS. Titanium: Corrosion Resistance

Both stainless steel fasteners and titanium fasteners are tough materials that could operate in harsh environments. However, these corrosion-resistant parts have different mechanisms.

Stainless steel fights against rusting with a thin and strong chromium oxide layer, which would regenerate quickly if it is damaged. The susceptibility of certain stainless steel varieties to corrosion depends on their chromium content. A higher proportion of chromium in the metal decreases the likelihood of rust formation. It should be mentioned that stainless steel is not resistant to all corrosive surroundings. Some chemical environments, for example, an aqueous environment containing chloride, may destroy this protective layer, and corrosion follows.

Similarly, titanium oxidizes and forms a thin layer on the surface to prevent the metal from further oxidation. Different from stainless steel, the layer adheres firmly to the metal surface, and will not degrade or peel off over time due to atmospheric exposure. It provides protection against a range of substances, such as organic acids, chloride solutions, and diluted forms of sulfuric and hydrochloric acids. Besides, titanium is a specialty metal with high corrosion resistance and physical stability. So, titanium fasteners possess higher corrosion resistance than stainless steel fasteners, and they are applied to extreme environments involving alkalis, acids, and other industrial chemicals.

In short, Titanium offers excellent corrosion resistance and mechanical stability, while stainless steel exhibits decent mechanical properties but lacks in corrosion resistance.

Stainless Steel VS. Titanium: Strength-to-Density Ratio

Strength-to-density ratio is another striking difference between stainless steel fasteners and titanium fasteners.

Titanium stands out for its strength-to-weight ratio. It has a density of 4.51g/cm³, which is much lower than steel of 7.8-8 g/cm3. In other words, titanium can provide the same amount of strength as steel at 40% of its weight. Such an excellent strength-to-density ratio makes titanium a desirable material to make planes, naval ships, space crafts, and missiles. You can also add aluminum, zirconium, and other elements to improve the properties of titanium parts.

Stainless Steel VS. Titanium: Biocompatibility

Both stainless steel bolts and titanium bolts are commonly used in the medical industry.

Because of good biocompatibility with human tissues and blood, titanium fasteners are typically employed to make heart stents, teeth implants, hip balls, and sockets in the human body. These apparatuses are also applied to make surgical instruments such as crutches and wheelchairs.

Stainless steel fasteners are not biocompatible and come with fewer uses. These devices are utilized to make operating tables and steam sterilizers in hygienic environments.

Stainless Steel VS. Titanium: How to Choose?

In a word, titanium fasteners are preferred by high-end industries like aerospace and the medical field because of better corrosion resistance, higher strength-to-density ratio, and good biocompatibility, while stainless steel fasteners are suitable for large-scale constructions that have fewer requirements on these properties.

Titanium products are popular in the aerospace industry which puts much more stress on weight than strength. They are also used in the dental and medical industries since titanium is biocompatible and nontoxic. Stainless steel has advantages over titanium when a large quantity is needed for construction. You’ll find stainless steel useful for its weldability and lower cost. At last, here is a table that provides a summary of the differences between stainless steel and titanium.

Is Tantalum Oxide a Semiconductor?

Tantalum oxide (Ta2O5) is a chemical compound that has been widely used in the field of electronics and optics due to its excellent properties, including a high refractive index, good thermal stability, and excellent dielectric properties. However, the question remains: is tantalum oxide a semiconductor?

Tantalum Pentoxide

The short answer is yes, tantalum oxide can exhibit semiconductor properties, but it depends on its composition and processing. Tantalum oxide can exist in different crystal structures, and the electrical properties of each structure can vary significantly. In its amorphous form, tantalum oxide behaves like a high-k dielectric material, meaning it has a high capacitance but low conductivity. However, when tantalum oxide is doped with certain impurities, it can exhibit semiconductor behavior.

One of the most common dopants used in tantalum oxide is niobium (Nb). Nb-doped tantalum oxide (TaNbO) has been extensively studied for its potential as a resistive switching material in non-volatile memory devices. In these devices, a thin layer of TaNbO is sandwiched between two metal electrodes. When a voltage is applied, the TaNbO layer undergoes a phase change from an insulating to a conductive state, allowing for data storage.

Another example of tantalum oxide exhibiting semiconductor behavior is in the form of nanocrystals. Tantalum oxide nanocrystals can be synthesized with a variety of sizes and shapes and have shown potential as a photocatalyst in solar cells. When excited by light, the nanocrystals can generate electron-hole pairs, leading to a photocurrent that can be used to generate electricity.

In addition to its potential in electronics and optics, tantalum oxide’s semiconductor properties also make it a promising material for sensing applications. TaNbO-based sensors have been developed to detect gases such as hydrogen and ammonia. These sensors work by measuring changes in the electrical conductivity of the TaNbO layer in the presence of the target gas.

In conclusion, tantalum oxide can exhibit semiconductor properties depending on its composition and processing. Doped tantalum oxide and tantalum oxide nanocrystals have shown potential in various applications, including non-volatile memory devices, solar cells, and sensors. With further research and development, tantalum oxide may find even more applications in the field of electronics and beyond.

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.

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.

Archive of: March 2023