?What is the hardest and toughest material on earth
Ask any science-loving geek about the harshest substance in the world, and their answer will undoubtedly be diamond. The word “diamond” has a Greek origin, and is read as “adames” meaning the unbreakable substance. For decades, people have used diamonds in cutting operations due to their extreme hardness, as well as being a very desirable type of jewelry for women because of their ability to interact with light, highlighting their beauty. But is it really the hardest material on the face of the Earth?
Well, if your answer is “yes,” then you are almost right. But scientists have discovered a potential competitor, which is believed to be harder than diamond.
?How is hardness measured
In materials science, evaluating the hardness of a material is extremely important, and the hardness value can be measured in different ways, depending on the situation and applicability.
Mohs scale of hardness
One of the most common hardness scales is the Mohs scale, designed by German scientist Friedrich Mohs in the 19th century. In this scale, hardness is defined as the amount of resistance that the measured material exhibits when attempted to be scratched by another material. The material's score is recorded on a scale from 0 to 10, with 10 indicating the material least affected by scratches (the hardest material), and 0 indicating the most affected material (the least hard material).
Mohs scale of hardness
On this scale, diamond scored a perfect score, clearly indicating that it is the most scratch-resistant natural material, while steel (known for its hardness) scored only four and a half degrees!
Not all researchers agreed to measure the value of hardness as scratch resistance alone, and they searched for another way to measure hardness, eventually developing an alternative technique for evaluating hardness.
Vickers hardness test
In this test, a solid, pyramid-shaped body called an indenter is used. The body is pressed against the tested material with a certain amount of force and for a specific period. Next, the surface area created on the material by the pyramid body is measured.
Also according to this test, diamond was the hardest on Earth.
?What makes a diamond solid
The answer lies in the molecular structure of this shiny element. Diamond consists of five carbon atoms that share electrons in the form of a tetrahedral lattice structure. The bond between carbon atoms is very strong and difficult to break at normal temperatures.
Diamond is a tetrahedral structure of carbon
Diamond has no free electrons, making it a poor electrical conductor, but it is an excellent conductor of heat, about five times better than copper, and due to this, it is used to make heatsinks for electronic circuits.
The legend of the invincible diamond
After reading this, you may feel like diamonds can't be beat, but that's not true. At high temperatures, diamonds become weak.
When diamond is heated to a temperature above 800 degrees Celsius, its chemical and physical properties change, and it becomes susceptible to chemical reaction with iron, making it an undesirable material in the steel manufacturing process.
Scientists have tried to find alternative materials with better chemical stability. In 2009, researchers at Shanghai Jiao Tong University and the University of Nevada claimed to have found two substances that may displace diamonds as the hardest material.
Wurtzite boron nitride w-BN
The structure of boron nitride is similar to that of diamond, but it consists mainly of boron and nitrogen atoms, along with carbon atoms. This element is extremely rare, and is only found as a result of certain types of volcanic eruptions.
In a 2009 simulation by researchers of the hexagonal wurtzite structure of boron nitride, they found that it is 18% harder than steel and chemically more stable than diamond at high temperatures.
Lonsdaleite
It consists of only carbon atoms, like diamond, but with a different structure, and is considered harder than boron nitride quartzite.
Interestingly, lonsdaleite is a cosmic substance that results from the collision of a graphite-rich meteorite with the Earth.
Vickers testing showed that lonsdaleite is 58% harder than diamond, making it the hardest material known on Earth.
but there is a problem!
The above claims are based on a computer simulation program, and no physical testing has been conducted to confirm the simulation results due to the difficulty of finding these materials.
However, simulations indicate that these materials have good chemical and thermal stability, and their industrial mass production could be a game-changer, and their stability at high temperatures makes them useful for spaceflight.
Generally, researchers try to find a substitute for diamond, but it was essentially formed by being subjected to the pressure of tons of rock, so we can say that it is used to dealing with pressure.
Source : websites