WHY ISN’T BERYLLIUM USED INSTEAD OF STEEL, WHEN IT IS LIGHTER AND 6 TIMES STRONGER?

 

Samples of pure beryllium. Image credit: W. Oelen via Wikimedia, CC-BY-SA-3.0

What is Beryllium?

Beryllium is a chemical element with the symbol Be and atomic number 4. It is a relatively rare, steel-gray metal that is lightweight, strong, and brittle at room temperature. Its main physical and chemical properties are:

• Beryllium is a steel-gray, strong, and lightweight metal. It has a density of 1.85 g/cm³, which is about one-third or about 30% lighter than aluminum, and 1.85 times that of water.
• It is relatively hard and brittle, with a melting point of 1,287 °C (2349 °F) and a boiling point of 2,471 °C (​4476 °F).
• It has high specific heat (1925 J·kg−1·K−1) and good thermal conductivity (200 W·m−1·K−1). Because of this property, it has one of the best heat dissipation characteristics per unit weight.
• It is relatively transparent to X-rays, making it useful in X-ray windows for medical and scientific applications.
• It is also a good conductor of electricity and has a high modulus of elasticity, which makes it useful in the aerospace industry. Its modulus of elasticity (also known as Young’s modulus) is 50% greater compared to steel (287 GPa vs. 190-210 GPa at room temperature).
• It has a low coefficient of linear thermal expansion (11.4×10−6 K−1), which means it is very stable under different thermal conditions.
• Beryllium is highly reactive and is not found in nature as a free element. It is typically found in compounds such as beryl and bertrandite.
• It reacts with both nonmetals and metals, and can form alloys with many other metals, such as copper, nickel, and aluminum.
• It is highly resistant to corrosion and oxidation, due to the formation of a thin oxide layer on its surface that protects it from further reactions.

This metal ball is made from beryllium. Note that the person who handles this sample uses protective gloves. Image credit: Aatze78 via Wikimedia, GFDL 1.2 license

Why isn’t beryllium used instead of steel? 2 reasons explained

Here are the two main reasons why Beryllium is not used instead of steel everywhere where theoretically possible:

Reason 1: Beryllium is toxic

This metal is highly toxic. Exposure to this metal can cause acute beryllium disease and chronic beryllium disease called berylliosis. Both of these conditions are life-threatening and may lead to a variety of respiratory illnesses. There are also ongoing debates about whether this material and its compounds can cause lung cancer when inhaled as dust or fumes.

How toxic is it? Its connection to adverse health effects has been known for a long time. The first occupational exposure limit for beryllium was proposed in 1949 by the former U.S. Atomic Energy Commission, now the U.S. Department of Energy. The relatively safe exposure limit was set to below 2.0 µg/m3.

In 1999, the U.S. Department of Energy enforced an even stricter exposure safety limit of 0.2 µg/m3 in its facilities, because this organization considered the existing limit not enough in order to protect the health of its employees. This limit, however, was not adopted nationwide.

For comparison, mercury and lead have occupational limits of around 100 µg/m3. This means that in terms of mass, beryllium is considered a much more toxic element.

The U.S. Environmental Protection Agency (EPA) classifies beryllium as a “likely human carcinogen”. This means that its role as a cause of disease is not clear, but is highly probable.

Reason 2: Berylium is rare

This metal is a relatively rare element in all of its natural forms, accounting for only about 0.0002-0.0004% of the Earth’s crust by weight. The global annual production of beryllium amounts to only roughly 280 tons in 2022, which is a minuscule amount, speaking in industrial terms.

For comparison, the total global production of crude steel was 1,878.5 Mt (million tons) in 2022. This means that there is absolutely no way to replace even a millionth part of steel consumed by various industries.

Certain parts of satellites, particularly measurement equipment, need this “wonder metal”. Image credit: Stephencdickson via Wikimedia, CC-BY-SA-4.0

Does it mean that beryllium cannot be used at all?

Despite being toxic, this chemical element is still used in different areas.

Due to its unique properties, this unique metal found its applications in a variety of industries, including aerospace, defense, and nuclear energy.

Beryllium is a good conductor of heat and electricity, and it is also transparent to X-rays, making it useful in medical imaging and other applications where X-rays are used.

Its alloys with copper are used in electrical contacts and springs, while its high stiffness and low weight make it useful in precision instruments and in the construction of lightweight structures.

Where can beryllium be found?

It is found in many minerals which facilitates its extraction. Sources include beryl (which is used as a gemstone), bertrandite, chrysoberyl, and phenakite.

Beryllium is also present in some types of igneous and metamorphic rocks, as well as in some soils and surface waters.

However, broadly speaking, beryllium is a rare resource – in the entire universe, in fact. It exists in the cores of stars, but it is depleted over time as it fuses into heavier elements.

Quantum computing is another field where beryllium is used. Image credit: NIST

Final word

Now you know that there are two main reasons why beryllium is not used instead of steel: its toxicity, and rarity. Despite these limitations, it is still used to produce components for aerospace and military industries, as well as in some types of medical equipment and measurement tools.

However, the occupational safety requirements are very strict when working with this metal and any of its compounds. Sometimes people who work with this element joke that it is much simpler to handle plutonium than beryllium.