Is Tungsten Magnetic: A Useful Guide
Tungsten is an interesting metal used in many industries like electronics and aerospace. But is tungsten magnetic?
In this guide, we’ll answer that question and explain why tungsten behaves the way it does. By the end, you’ll have a better understanding of its magnetic properties.
Chemical and Physical Properties of Tungsten
Tungsten is a rare, silver-white metal that you can count on for strength and heat resistance. It is part of Group VIB in the periodic table and has unique chemical and physical properties.
Propriedades físicas
Tungsten, with the symbol W and atomic number 74, has the highest melting point of any metal at 3422°C (6192°F) and a boiling point of 5927°C. That’s why it’s perfect for use in very hot environments.
With a density of 19.3g/cm³, it is as heavy as gold and much heavier than steel. Tungsten is extremely hard, especially in its carbide form, making it as hard as diamond and great for tools that need to resist wear.
Although its electrical conductivity is relatively low compared to other metals, tungsten’s ability to withstand high temperatures makes it suitable for some electrical applications.
With a thermal conductivity of 170 W/m·K, it performs adequately in heat transfer but doesn’t match the conductivity of metals like copper.
Tungsten has high tensile strength that makes it resistant to deformation under stress so it’s perfect for heavy-duty applications.
Propriedades químicas
When it comes to chemical properties, Tungsten can exist in several oxidation states, including +2, +3, +4, +5, and +6; +6 is the most stable and common.
It is highly resistant to oxidation at room temperature, but at elevated temperatures, it forms tungsten trioxide (WO₃).
While tungsten is resistant to most acids, it will dissolve in aqua regia– a mixture of hydrochloric and nitric acids, forming soluble tungsten compounds.
When reacting to strong bases like sodium hydroxide (NaOH), tungsten forms tungstate salts. Tungsten also forms a variety of complex compounds such as tungsten hexacarbonyl (W(CO)₆) and tungstate ions (WO₄²⁻).
Though less common, tungsten can form hydrides like tungsten hexahydride (WH₆). Additionally, tungsten is used as a catalyst in several chemical processes, including petroleum refining and organic synthesis, due to its catalytic properties.
Magnetic Properties and Classification
Magnetic materials fall into three main types– ferromagnetic, paramagnetic, and diamagnetic. Ferromagnetic materials like iron are strongly attracted to magnets and stay magnetized even after the magnet is removed.
Paramagnetic materials are weakly attracted to magnets and don’t stay magnetized once the magnet is removed. Diamagnetic materials are repelled by magnets.
Tungsten is paramagnetic. It has unpaired electrons, so it’s weakly attracted to magnetic fields. However, this attraction is temporary, and tungsten doesn’t stay magnetized once the field is gone.
Is Tungsten Magnetic?
Pure tungsten is not magnetic. It doesn’t attract magnets or become magnetized like iron or nickel.
Although tungsten is known for its high melting point, extreme hardness, and density, these properties don’t contribute to magnetism.
Tungsten’s Electron Configuration and Magnetic Behavior
Tungsten has the electron configuration [Xe] 4f^14 5d^4 6s^2. While it has unpaired electrons in its 5d orbital, which might give magnetic properties, tungsten behaves mostly like a diamagnetic material.
Tungsten doesn’t have the structure needed to be strongly magnetic like ferromagnetic materials. Any weak attraction is canceled out by its repelling behavior.
Magnetic Susceptibility of Tungsten
As mentioned above, tungsten is classified as a paramagnetic material. This means it’s weakly attracted to magnetic fields but doesn’t retain magnetism when the magnetic field is removed.
The magnetic susceptibility of tungsten is quite low, meaning its magnetic attraction is very weak compared to materials like iron. In practical terms, tungsten is considered non-magnetic.
Why Tungsten Experiences Paramagnetic Properties
Tungsten’s paramagnetic properties are due to its electron configuration. The unpaired electrons in its 5d orbital can align with an external magnetic field, but this alignment is weak and temporary.
Once the magnetic field is gone, the tungsten atoms return to their normal state, and the magnetism disappears. This makes tungsten’s magnetic properties very faint and short-lived.
Factors that Affect Tungsten’s Magnetism
Tungsten’s magnetic properties can be affected by a few different factors, such as the following:
Temperatura
Temperature has a big effect on how tungsten responds to magnetic fields. According to Curie’s law, when the temperature goes up, tungsten becomes less magnetic.
So, if you increase the temperature, its magnetic properties weaken. But if you cool it down, tungsten’s magnetic properties get stronger because the lower temperature helps the material align better with magnetic fields.
Applied Magnetic Field
When you expose tungsten to a strong magnetic field, the electrons inside it temporarily align, making it weakly magnetic. But this effect doesn’t last.
Once you remove the magnetic field, tungsten loses its weak magnetism and returns to normal. So, the strength of the magnetic field you apply will affect how much tungsten gets magnetized.
Binder Content
In tungsten alloys, binder elements hold the different metals together. These binders can change how tungsten behaves in a magnetic field.
For example, cobalt, a common binder, can make tungsten slightly more magnetic. On the other hand, nickel can weaken or eliminate any magnetic properties, making tungsten non-magnetic.
Composição
Tungsten’s makeup, especially the number of unpaired electrons and how they’re arranged, affects its magnetic behavior. The more unpaired electrons tungsten has and the way they’re aligned, the stronger its magnetic response will be.
So, the exact composition of tungsten determines how it reacts to magnets.
Is Tungsten Carbide Magnetic?
No, tungsten carbide is not magnetic. Tungsten carbide is made up of tungsten and carbon atoms. Tungsten, by itself, has weak magnetic properties.
When it combines with carbon to form tungsten carbide, the strong bonds between the atoms prevent it from becoming magnetic. This means tungsten carbide doesn’t attract magnets or become magnetized.
However, the binder metals used to make tungsten carbide can affect how magnetic it is. Binder metals like cobalt, nickel, and iron are magnetic. The more of these metals are used, especially cobalt, the more magnetic tungsten carbide will be.
Grades of Tungsten Carbide and Magnetic Properties
The magnetic properties of tungsten carbide can vary depending on the grade and the binder content. Here’s how different types of tungsten carbide behave magnetically:
Pure Tungsten Carbide: This grade is completely non-magnetic. Since it doesn’t contain any binder materials, it doesn’t react to magnetic fields.
Grades with 6-15% Cobalt Content: These grades are weakly magnetic. The small amount of cobalt added to the mixture makes it slightly magnetic, though not so noticeable.
Higher Cobalt Content (15-30%): Tungsten carbide with higher cobalt content is more noticeably magnetic. As the cobalt content increases, so does the material’s magnetic permeability.
Iron or Nickel Binders: Tungsten carbide made with iron or nickel binders is less magnetic than those with cobalt. While these metals are magnetic, they don’t contribute as strongly to the material’s overall magnetism as cobalt does.
Is a Tungsten Ring Magnetic?
A tungsten ring can be magnetic or not, depending on what it’s made of. Pure tungsten is not magnetic, so if your ring is made from pure tungsten, it won’t stick to a magnet.
Tungsten doesn’t have the magnetic properties of metals like iron, nickel, or cobalt. However, most tungsten rings are made from alloys, which means other metals are mixed in.
These metals can make your tungsten ring magnetic:
Cobalt-Bound Tungsten Carbide: If your ring has cobalt, it will be magnetic. Cobalt is a ferromagnetic metal, which means it can attract magnets easily.
Nickel-Bound Tungsten Carbide: If your ring contains nickel, it’s less magnetic but might still react to a strong magnet.
Common Tungsten Objects and Magnetism
Let’s look at some common tungsten products and their magnetic properties.
Tungsten Rings
Most tungsten rings aren’t made from pure tungsten. They’re often mixed with other metals, which can make them slightly magnetic.
Tungsten Carbide
Tungsten carbide is a mix of tungsten and carbon, usually held together by metals like cobalt or nickel. The magnetism depends on the binder element.
Tungsten Rods
Pure tungsten rods are non-magnetic. If your tungsten rod doesn’t have other metals mixed in, it won’t stick to a magnet.
Tungsten Powder
Pure tungsten powder isn’t magnetic. However, recycled or contaminated powder might have small amounts of magnetic materials, making it slightly magnetic.
Tungsten Welding
Tungsten welding electrodes, like thoriated tungsten, can be a little magnetic. This happens because of the materials added during production, like thorium, which creates a magnetic effect.
Conclusão
The magnetism of tungsten products can depend on how they were made, what metals were added, or if they’ve been recycled and picked up magnetic contaminants.
If you’re working with tungsten products, DEK is a manufacturing company that can help you create high-quality tungsten items tailored to your needs. Contactar a DEK and get a free quote.
