When we think of hardness, diamonds have long been hailed as the epitome of strength. For millennia, they were considered the hardest known material on Earth, captivating our fascination with their brilliance and durability. However, recent advancements in materials science have reshaped our understanding of hardness, revealing that diamonds no longer claim the top spot on the hardness hierarchy. They now rank at a surprising #7.
So, can you guess which material has emerged as the new champion of strength?
To comprehend this shift in the hardness hierarchy, we must delve into the remarkable properties of carbon, the elemental building block of many incredibly strong materials.
One of the key factors behind their strength is carbon’s ability to form strong chemical bonds with other carbon atoms. These bonds are known as covalent bonds, and they involve the sharing of electrons between atoms, resulting in a stable and robust molecular structure.
When carbon atoms bond together, they can create an astonishing variety of structures, each with its own set of unique properties. The most famous of these structures is indeed the diamond, a crystalline lattice formed by carbon atoms arranged in a specific pattern. In a diamond, each carbon atom forms four strong covalent bonds with four neighbouring carbon atoms, creating an incredibly rigid and three-dimensional network. This arrangement makes diamonds exceptionally hard, resistant to deformation, and able to withstand immense pressure.
However diamond is no longer the strongest material on Earth, the world of carbon-based materials holds even greater surprises.
The Hardness Hierarchy
In our exploration of materials that surpass diamonds in strength, let us begin with silicon carbide. This compound, naturally found as small fragments of the mineral moissanite, possesses a hardness that exceeds diamonds. Through a process called sintering, silicon carbide grains can be bonded together to create exceptionally hard ceramic materials. Not only does silicon carbide have various industrial applications, but it also exhibits valuable semiconductor properties.
Moving from inorganic to biological realms, let us turn our attention to spider silk. Known for its toughness, spider silk boasts a higher strength-to-weight ratio than conventional materials like aluminium or steel. Among all the spiders in the world, Darwin’s bark spider produces the toughest silk, which is ten times stronger than Kevlar. Imagine a strand of Darwin’s bark spider silk that could circle the entire Earth, weighing only a pound. Such marvels of nature inspire scientists to explore the potential applications of spider silk in various fields.
Our journey into the world of exceptional materials takes another intriguing turn with self-assembling nanoparticles. These nanospheres, with diameters ranging from 50 to 2 nanometers, possess incredible stiffness and are as hard as diamonds. They can arrange themselves into intricate structures, exhibiting remarkable strength and toughness. Scientists envision the use of these self-assembling nanospheres in creating custom materials with applications in water purification, solar cells, catalysts, and even printable body armour tailored to specific needs.
The Reigning Champion: Graphene’s Dominance
While the materials we’ve explored thus far demonstrate impressive strength, there is one material that stands above them all as the undisputed champion: graphene. Graphene is a hexagonal carbon lattice that is astonishingly thin, consisting of a single layer of atoms. Its incredible strength-to-thickness ratio makes it the strongest material known on Earth.
Beyond its strength, graphene possesses exceptional electrical conductivity and transparency. Its discovery led to the 2010 Nobel Prize in Physics, awarded to Andre Geim and Konstantin Novoselov. Since then, graphene has found its way into numerous applications and industries, propelling it toward becoming a multibillion-dollar industry within a few decades.
The potential applications of graphene are vast. From revolutionizing electronics to enhancing energy storage and improving water purification systems, graphene’s properties make it an incredibly versatile and promising material. Its remarkable strength combined with its electrical and thermal conductivity opens up possibilities we could only dream of a few decades ago.
As we delve into the realm of materials science, we uncover a captivating truth: diamonds no longer hold the title of the strongest material. Through the exploration of carbon-based and other cutting-edge substances, we have unveiled a new champion—graphene. Its exceptional properties and endless possibilities mark a remarkable milestone in our quest for stronger, more versatile materials.
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