Nickel hydride

Nickel hydride describes an alloy made by combining nickel and hydrogen. Hydrogen's content in nickel hydride is up to 0.002% by weight.

Hydrogen acts as a hardening agent, preventing dislocations in the nickel atom crystal lattice from sliding past one another. Varying the amount of alloying hydrogen and the form of its presence in the nickel hydride (precipitated phase) controls qualities such as the hardness, ductility, and tensile strength of the resulting nickel hydride. Nickel hydride with increased hydrogen content can be made harder and stronger than nickel, but such nickel hydride is also less ductile than nickel. Loss of ductility occurs due to cracks maintaining sharp points due to suppression of elastic deformation by the hydrogen, and voids forming under tension due to decomposition of the hydride. Hydrogen embrittlement can be a problem in nickel in use in turbines at high temperatures.