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Material called as wurtzite boron nitride(w-ND) is the newly discovered hardest material on the earth.This material has been proved to be more harder than the diamond.
The new hardest material has the greater indentation strength than the diamond.But a much harder material than the wurtzite boron nitride has been found to be lonsdaleite (also called hexagonal diamond, since it’s made of carbon and is similar to diamond) which is 58 times harder than the diamond setting a new record.

“The new finding from our results is that large normal compressive pressures under indenters can transform certain materials (such as w-BN and lonsdaleite) into new superhard structures that are harder than diamond,” coauthor Changfeng Chen from the University of Nevada, Las Vegas, told PhysOrg.com. “This is a new mechanism that can be used to design new superhard materials.”


The scientists explain that the hardness of the materials are due to the change in the structure under compressional pressure.Normal compressive pressures under indenters cause the materials to undergo a structural phase transformation into stronger structures, conserving volume by flipping their atomic bonds. The scientists explain that w-BN and lonsdaleite have subtle differences in the directional arrangements of their bonds compared with diamond, which is responsible for their unique structural reaction.

• w-BN increases its strength by 78 percent compared with its strength before bond-flipping.
• w-BN reaches an indentation strength of 114 GPa (billions of pascals), well beyond diamond’s 97 GPa under the same indentation conditions.
• In lonsdaleite indentation strength of 152 GPa, which is 58 percent higher than the corresponding value of diamond is calculated.

“Lonsdaleite is even stronger than w-BN because lonsdaleite is made of carbon atoms and w-BN consists of boron and nitrogen atoms,” Chen explained. “The carbon-carbon bonds in lonsdaleite are stronger than boron-nitrogen bonds in w-BN. This is also why diamond (with a cubic structure) is stronger than cubic boron nitride (c-BN).”