[Physical materials]the world’s top ten superhard materials

1. Diamond 

Diamond is the hardest naturally occurring substance currently found on Earth. Diamond has a Mohs hardness of 10, and its absolute hardness is 4 times that of corundum and 8 times that of quartz. There are two main methods for synthetic diamond, high temperature and high pressure method and chemical vapor deposition method. Diamonds are used in a wide range of applications, such as crafts, cutting tools in industry, and precious gemstones.

2. Graphene

Graphene is a two-dimensional material separated from graphite material and composed of carbon atoms with only one layer of atoms. The breaking strength of graphene is 200 times higher than that of the best steel. At the same time, it is very elastic and can stretch up to 20% of its own size. As a new type of nanomaterial that is ultra-thin, super strong, and has excellent electrical and thermal conductivity, graphene is called "black gold" and the "king of new materials." Scientists even predict that graphene will "completely change the 21st century." It may set off a disruptive new technology and new industrial revolution sweeping the world.

3. Carboyne

Carboynes are chains of carbon atoms held together by double bonds or alternating single and triple bonds. Carboyne is considered the strongest material in the world, 40 times stronger than diamond and twice as strong as graphene. Carboyne will have a very important use in the future development of ultra-high-strength equipment.

4. Carbon nanotubes

Carbon nanotubes can be regarded as rolled graphene sheets, so according to the number of layers of graphene sheets, they can be divided into: single-walled carbon nanotubes and multi-walled carbon nanotubes. Carbon nanotubes are as hard as diamond, yet flexible and can be stretched. Carbon nanotubes are 100 times stronger than the same volume of steel, but their weight is only 1/6 to 1/7 of the latter. Carbon nanotubes are therefore called "super fibers". In recent years, with the deepening of research on carbon nanotubes and nanomaterials, their broad application prospects have also been continuously revealed.

5. Borene

Borene has the same hexagonal lattice arrangement as carbon in graphene, but with an additional boron atom at the center of each hexagon. Borene is stronger than graphene in some directions. With such superior mechanical properties, coupled with special electrical and thermal properties, borophene will have broad application prospects. Because of its superior electrical, mechanical, and thermal properties, borophene has high hopes from the scientific community and may become another "miraculous nanomaterial" after graphene.

6. Aerogel

Aerogel, as the world's lightest solid, has been selected into the Guinness Book of World Records. At present, the lightest silicone aerogel has only 0.16 mg per cubic centimeter, which is slightly lower than the density of air, so it is also called "frozen smoke" or "blue smoke". Airgel may seem "frail", but it is actually very strong and durable. It can withstand pressures thousands of times its own mass and will melt only when the temperature reaches 1,200 degrees Celsius. In addition, its thermal conductivity and refractive index are also very low, and its insulation ability is 39 times stronger than the best fiberglass. Due to these properties, aerogel has become an irreplaceable material in aerospace exploration. Both the Russian Mir space station and the American Mars Pathfinder probe use it for thermal insulation.

7. Nanowires

Nanowires are one-dimensional materials that are constrained laterally to less than 100 nanometers and have an aspect ratio above 1,000. Carbon nanotubes are the star material in the nanowire family.Depending on the constituent materials, nanowires can be divided into different types, including metallic nanowires, semiconductor nanowires, and insulator nanowires.Typically, as their size decreases, nanowires exhibit better mechanical properties than bulk materials, becoming stronger and tougher. Nanowires have the potential to play an important role in electronic, optoelectronic and nanoelectronic mechanical devices. It can also be used as an additive in composites, as a wiring in quantum devices, as a field emitter and as a biomolecular nanosensor.

8. Boron nitride

Boron nitride is a crystal composed of nitrogen atoms and boron atoms. Chemical composition is 43.6% boron and 56.4% nitrogen, with four different variants: hexagonal boron nitride (HBN), rhombohedral boron nitride (RBN), cubic boron nitride (CBN) and wurtzite nitrogen Boron (WBN).Cubic boron nitride is harder than diamond, and other types of boron nitride are slightly weaker than diamond. Boron nitride has high temperature resistance, corrosion resistance, good thermal conductivity, low thermal expansion coefficient, good thermal shock resistance, good chemical stability, good lubricity, and excellent electrical properties. It is used in cutting-edge electronics, metallurgy, chemical industry, aerospace, etc. It has an extremely wide range of uses in technology.

9. Emery

Silicon carbide is a carbide accidentally discovered in the laboratory by the American Acheson during the fused diamond experiment in 1891. At that time, he mistakenly thought it was a mixture of diamond, so it was named emery. Silicon carbide is very hard, with a Mohs hardness of 9.5, slightly lower than diamond (level 10). It has excellent thermal conductivity, is a semiconductor, and can resist oxidation at high temperatures.

10. Titanium alloy

Titanium alloy is an alloy based on titanium and added with other elements. There are hundreds of titanium alloys that have been developed in the world, and there are 20 to 30 of the most famous alloys. Titanium alloys have the characteristics of high strength, good corrosion resistance, and high heat resistance. They are widely used in industrial production, mainly for making aircraft engine compressor parts, followed by structural parts for rockets, missiles, and high-speed aircraft.