With heat treatment the chemical nickel layer is treated at high temperatures to obtain a certain compactness of the final layer, improving its adherence, and to increase the level of superficial hardness.

The metallic detail, as soon as it is treated, has a standard superficial hardness of about 500 HV100.

The situation of the crystal lattice, as soon as the layer is placed, is not stable and it is called α-nickel (compact hexagonal crystal shape). Thanks to the heat treatment it can transformed to β-nickel (face-centred cubic shape), which presents a more stable composition and a higher superficial hardness (about 1000 HV100).