Which material is the most durable? Diamond Hardness Determination

Each of you knows that diamond remains the standard of hardness today. When determining the mechanical hardness of materials existing on earth, the hardness of diamond is taken as a standard: when measured by the Mohs method - in the form of a surface sample, by the Vickers or Rockwell methods - as an indenter (as a harder body when studying a body with less hardness). Today, there are several materials whose hardness approaches the characteristics of diamond.

In this case, original materials are compared based on their microhardness according to the Vickers method, when the material is considered superhard at values of more than 40 GPa. The hardness of materials can vary depending on the characteristics of the sample synthesis or the direction of the load applied to it.

Fluctuations in hardness values from 70 to 150 GPa are a generally established concept for solid materials, although 115 GPa is considered to be the reference value. Let's look at the 10 hardest materials, other than diamond, that exist in nature.

10. Boron suboxide (B 6 O) - hardness up to 45 GPa

Boron suboxide has the ability to create grains shaped like icosahedrons. The formed grains are not isolated crystals or varieties of quasicrystals, but are peculiar twin crystals, consisting of two dozen paired tetrahedral crystals.

10. Rhenium diboride (ReB 2) - hardness 48 GPa

Many researchers question whether this material can be classified as a superhard type of material. This is caused by the very unusual mechanical properties of the joint.

The layer-by-layer alternation of different atoms makes this material anisotropic. Therefore, hardness measurements are different in the presence of different types of crystallographic planes. Thus, tests of rhenium diboride at low loads provide a hardness of 48 GPa, and with increasing load the hardness becomes much lower and is approximately 22 GPa.

8. Magnesium aluminum boride (AlMgB 14) - hardness up to 51 GPa

The composition is a mixture of aluminum, magnesium, boron with low sliding friction, as well as high hardness. These qualities could be a boon for the production of modern machines and mechanisms that operate without lubrication. But using the material in this variation is still considered prohibitively expensive.

AlMgB14 - special thin films created using pulsed laser deposition, have the ability to have a microhardness of up to 51 GPa.

7. Boron-carbon-silicon - hardness up to 70 GPa

The basis of such a compound provides the alloy with qualities that imply optimal resistance to negative chemical influences and high temperatures. This material is provided with a microhardness of up to 70 GPa.

6. Boron carbide B 4 C (B 12 C 3) - hardness up to 72 GPa

Another material is boron carbide. The substance began to be used quite actively in various fields of industry almost immediately after its invention in the 18th century.

The microhardness of the material reaches 49 GPa, but it has been proven that this figure can be increased by adding argon ions to the structure of the crystal lattice - up to 72 GPa.

5. Carbon-boron nitride - hardness up to 76 GPa

Researchers and scientists from all over the world have long been trying to synthesize complex superhard materials, with tangible results already achieved. The components of the compound are boron, carbon and nitrogen atoms - similar in size. The qualitative hardness of the material reaches 76 GPa.

4. Nanostructured cubonite - hardness up to 108 GPa

The material is also called kingsongite, borazon or elbor, and also has unique qualities that are successfully used in modern industry. With cubonite hardness values of 80-90 GPa, close to the diamond standard, the force of the Hall-Petch law can cause their significant increase.

This means that as the size of the crystalline grains decreases, the hardness of the material increases - there are certain possibilities for increasing it up to 108 GPa.

3. Wurtzite boron nitride - hardness up to 114 GPa

The wurtzite crystal structure provides high hardness to this material. With local structural modifications, during the application of a particular type of load, the bonds between atoms in the lattice of the substance are redistributed. At this moment, the quality hardness of the material increases by 78%.

2. Lonsdaleite - hardness up to 152 GPa

Lonsdaleite is an allotropic modification of carbon and has a clear similarity to diamond. A solid natural material was discovered in a meteorite crater, formed from graphite, one of the components of the meteorite, but it did not have a record level of strength.

Scientists proved back in 2009 that the absence of impurities can provide hardness exceeding the hardness of diamond. High hardness values can be achieved in this case, as in the case of wurtzite boron nitride.

1. Fullerite - hardness up to 310 GPa

Polymerized fullerite is considered in our time to be the hardest material known to science. This is a structured molecular crystal, the nodes of which consist of whole molecules rather than individual atoms.

Fullerite has a hardness of up to 310 GPa, and it can scratch a diamond surface like regular plastic. As you can see, diamond is no longer the hardest natural material in the world; harder compounds are available to science.

So far, these are the hardest materials on Earth known to science. It is quite possible that new discoveries and breakthroughs in the field of chemistry/physics will soon await us, which will allow us to achieve higher hardness.

Still think that diamond is the hardest substance on our planet? Last century! In our TOP 10 - the hardest substances on the planet, and in them only in fourth place.

1 Ultrahard fullerite

Scratch a diamond? Easily. Ultra-hard fullerite is suitable for this. The faces of this crystal contain entire fulleron molecules, which makes it unusually strong, approximately three times stronger than diamond.

Unlike completely artificial fullerite, lonsdaleite can be found in places where asteroids collide with the earth's surface. A special feature of this substance is its ability to be modified under pressure. If the external load increases, lonsdaleite rearranges its structure to become even stronger.

A similar mechanism is triggered by the bronze medalist of our Top Ten Solid Substances on Earth. This is wurtzite boron nitride. When the pressure on this material increases, it becomes almost twice as hard as its normal state.

Natural diamond still clings to its position, however... few people know that diamonds also vary in hardness. Depending on the quality of the stone, its hardness ranges from 70 to 150 gigapascals. But still, he deserves a solid four.

All these are names of the same substance - cubic boron nitride, discovered back in 1985. It is interesting to know that borazon is superior to diamond in some ways - its combustion temperature is almost twice the combustion temperature of diamond.

But this substance exists only potentially and has so far been proven only theoretically. However, when it is created, Boron Carbon Nitride (c-BC2N) will be harder than diamond in some aspects.

Boron carbide is one of the old-timers of our top ten hardest substances on the planet. 2016 marks 123 years since its opening. And yet, it still holds its mark - it is one of the most refractory and chemically resistant substances, insoluble even in boiling acids.

Diboride is exceptionally strong in one direction of its crystal lattice. To obtain this substance, magnesium diboride is mixed with osmium chloride and kept at a temperature of +1000C for three days. Both substances dissolve even with water, but the resulting crystals are much harder.

Another crystal that steps on the heels of the diamond. Its crystal lattice in certain directions is even harder than this natural mineral. At the same time, according to others, it is five to six times softer. So he deserves 9th place.

A three-component substance that has perfect glide and excellent hardness. The material exists in the form of the finest spray.

The precious stone some time ago lost its title of the hardest material in the world, giving way to artificial nanomaterials of slightly greater hardness. Today, a rare natural substance looks set to leave all others behind - it is 58% harder than diamond.

Zicheng Pan from Shanghai Jiao Tong University and his colleagues modeled how atoms in two substances supposedly having the properties of very hard materials would respond to a special sensor.

Extreme conditions

The first is wurtzite boron nitride, which has a structure similar to diamond, but consists of different atoms.

The second is the mineral lonsdaleite, or hexagonal diamond, made up of carbon atoms like diamond, but they are organized differently.
Modeling showed that wurtzite boron nitride can withstand 18% more impact than diamond, and lonsdaleite - 58% more. If the results are confirmed by physical experiments, both materials will be much harder than any known substance.

But it will not be easy to carry out such tests, because both materials are not often found in nature.

The rare substance lonsdaleite is formed when meteorites containing graphite fall to Earth, while wurtzite boron nitride is formed during volcanic eruptions under high temperatures and pressure.

Flexibility

If successful, wurtzite boron nitride may become the more useful of the two due to its resistance to oxygen at higher temperatures than diamond. This makes it ideal for use on the ends of cutting and drilling tools operating at very high temperatures, or as corrosion-resistant films on the surfaces of spacecraft, for example.

Paradoxically, wurtzite boron nitride owes its hardness to the flexibility of the bonds between the atoms that form it. When the material is stressed, some bonds change direction by almost 90º to relieve stress. After diamond and wurtzite boron nitride were subjected to the same process, something in the structure of wurtzite boron nitride made it nearly 80% harder, says study co-author Changfeng Chen of the University of Nevada, Las Vegas.

Scientists emphasize that in order to prove the theory, single crystals of each material are needed. There is currently no way to isolate or grow such crystals.

Today there is no unified classification of semi-precious stones, there is only a conditional division. You can find out everything about the stones and their description properties on the website http://www.catalogmineralov.ru/cont/poludragocennye_kamni.htm. When deciding to give a gift with a semi-precious stone to a loved one, first get to know the stone.

American researchers from Indiana University in Bloomington managed to identify a substance that may be the most durable in the Universe. This substance was discovered in neutron stars. Because of its specific shape, researchers called it “nuclear paste.”

Scientists theorize that this material forms about a kilometer below the surface of a neutron star: atomic nuclei are compressed so close that they merge into clumps of matter, a dense mixture of neutrons and protons. They are usually in the form of drops, tubes or sheets. Deeper still in a neutron star, nuclear matter completely takes over and a huge atomic nucleus is formed.

In the process of computer modeling, experts estimated the force that must be expended to stretch the “nuclear paste.” It turned out that this substance is stronger than any other known substance in the Universe. Physicists are still striving to find real evidence of the existence of nuclear paste. Neutron stars tend to spin very quickly and, as a result, can emit ripples in space - gravitational waves - that interfere with the study of the materials that make up the stars.

One way scientists are guided is by focusing their research on the internal structures of stars, which may support the existence of mountains on the surface of these celestial bodies. Due to strong gravity, the height of mountains is usually no more than a few centimeters, but the “nuclear paste” can contribute to the appearance of larger irregularities several tens of centimeters high.

A map of the world is a common thing for us - since school, we know everything about climate, division into areas and the location of a particular country. But recently, British scientists from the University of Plymouth made a discovery that will essentially force the textbooks to be rewritten.

Durable materials have a wide range of uses. There is not only the hardest metal, but also the hardest and most durable wood, as well as the most durable artificially created materials.

Where are the most durable materials used?

Heavy-duty materials are used in many areas of life. Thus, chemists in Ireland and America have developed a technology by which durable textile fiber is produced. A thread of this material has a diameter of fifty micrometers. It is created from tens of millions of nanotubes, which are bonded together using a polymer.

The tensile strength of this electrically conductive fiber is three times higher than that of the web of an orb-weaving spider. The resulting material is used to make ultra-light body armor and sports equipment. The name of another durable material is ONNEX, created by order of the US Department of Defense. In addition to its use in the production of body armor, the new material can also be used in flight control systems, sensors, and engines.

There is a technology developed by scientists, thanks to which strong, hard, transparent and lightweight materials are obtained through the transformation of aerogels. Based on them, it is possible to produce lightweight body armor, armor for tanks and durable building materials.

Novosibirsk scientists have invented a plasma reactor of a new principle, thanks to which it is possible to produce nanotubulene, a super-strong artificial material. This material was discovered twenty years ago. It is a mass of elastic consistency. It consists of plexuses that cannot be seen with the naked eye. The thickness of the walls of these plexuses is one atom.

The fact that the atoms seem to be nested into each other according to the “Russian doll” principle makes nanotubulene the most durable material of all known. When this material is added to concrete, metal, and plastic, their strength and electrical conductivity are significantly enhanced. Nanotubulene will help make cars and planes more durable. If the new material comes into widespread production, then roads, houses, and equipment can become very durable. It will be very difficult to destroy them. Nanotubulene has not yet been introduced into widespread production due to its very high cost. However, Novosibirsk scientists managed to significantly reduce the cost of this material. Now nanotubulene can be produced not in kilograms, but in tons.

The hardest metal

Among all known metals, chromium is the hardest, but its hardness largely depends on its purity. Its properties are corrosion resistance, heat resistance and refractoriness. Chrome is a metal with a whitish-blue hue. Its Brinell hardness is 70-90 kgf/cm2. The melting point of the hardest metal is one thousand nine hundred seven degrees Celsius with a density of seven thousand two hundred kg/m3. This metal is found in the earth's crust in the amount of 0.02 percent, which is significant. It is usually found in the form of chromium iron ore. Chromium is mined from silicate rocks.

This metal is used in industry, smelting chromium steel, nichrome, and so on. It is used for anti-corrosion and decorative coatings. Stone meteorites falling to Earth are very rich in chromium.

The most durable tree

There is wood that is stronger than cast iron and can be compared to the strength of iron. We are talking about “Schmidt Birch”. It is also called Iron Birch. Man does not know a stronger tree than this. It was discovered by a Russian botanist named Schmidt while in the Far East.

Wood is one and a half times stronger than cast iron, and its bending strength is approximately equal to that of iron. Because of these properties, iron birch could sometimes replace metal, because this wood is not subject to corrosion and rotting. The hull of a vessel made of Iron Birch does not even need to be painted; the vessel will not be destroyed by corrosion, and it is also not afraid of acids.

A Schmidt birch cannot be pierced by a bullet; you cannot cut it down with an axe. Of all the birches on our planet, the Iron Birch is the longest-living one - it lives for four hundred years. Its habitat is the Kedrovaya Pad Nature Reserve. This is a rare protected species that is listed in the Red Book. If it were not for such rarity, the ultra-strong wood of this tree could be used everywhere.

But the tallest trees in the world, redwoods, are not very durable material.

The strongest material in the Universe

The most durable and at the same time lightest material in our Universe is graphene. This is a carbon plate, the thickness of which is only one atom, but it is stronger than diamond, and the electrical conductivity is a hundred times higher than the silicon of computer chips.

Graphene will soon leave scientific laboratories. All scientists in the world today talk about its unique properties. So, a few grams of material will be enough to cover an entire football field. Graphene is very flexible and can be folded, bent, or rolled.

Possible areas of its use are solar panels, cell phones, touch screens, super-fast computer chips.
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