The People’s Liberation Army’s Z-10 attack helicopter is now equipped with extra armor made with the lightweight, structurally rigid graphene semimetal, the latest addition to protect the chopper’s airframe without eating into its effective payload.

Footage aired by state broadcaster China Central Television earlier this month has piqued interest among military observers after showing a Z-10 with an extra armor module near its tandem cockpit landing at an unspecified airstrip.

Previous models of the Z-10 series did not have extra armor due to engine constraints and designers with the state-owned Aviation Industry Corp of China had to do away other additional protective gear so the helicopter could carry a sufficient payload.

The Z-10 is primarily designed for anti-tank warfare but has secondary air-to-air capability as well. In aerial warfare Z-10s often need to fly low to attack ground targets, making them vulnerable to anti-aircraft fire.

Chinese researchers at the Beijing Institute of Aeronautical Materials developed graphene materials that could be used to make armor for military vehicles and fighters as well as bulletproof vests for soldiers. It is a novel semimetal that could be about 200 times stronger than steel and weigh less than one gram per cubic meter.

Graphene is an allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice.

As the basic structural element of many other allotropes of carbon, such as graphite, diamond, charcoal, etc, graphene has many uncommon properties, such as being the strongest material ever tested, and it also conducts heat and electricity efficiently.

The bottom and sides of the Z-10 cockpit are protected by a composite graphene armor, and so are the engines and the fuel tank in the middle of the fuselage.

The PLA announced that all of its ground force aviation units had been equipped with the Z-10s since 2016.