TTransport measurements show that the resistance of the graphene bilayer after irradiation with an electron beam increases significantly, and the linear dependence of the current on voltage in the bias voltage range from –1 to 1 V changes to nonlinear. This indicates the appearance of a barrier for carriers in the irradiated area. This result is explained within the framework of the theory of a chemically induced phase transition associated with the formation of sp3 bonds of carbon with hydrogen and oxygen. When a local area of the sample is irradiated with a focused electron beam, hydrogen is released from the destroyed polymer on one side, and oxygen is taken from the langasite substrate on the other side, forming strong bonds with graphene. As a result, a stable diamane nanostructure is formed in this region. The developed model of a diamane film located on a langasite substrate and functionalized with H and O atoms confirms experimental observations. The processes of nucleation of diamane from bigraphene on a metal substrate (platinum, nickel, copper) were modeled and compared, and the energy benefits of these processes were assessed. It was shown that nucleation on a nickel substrate occurs barrier-free due to the formation of metal-carbon chemical bonds, while the nucleation process on copper and platinum has an energy barrier, which allows us to conclude that platinum is preferably used as a source of hydrogen rather than an active substrate in such processes. A moment tensor potential has been prepared using machine learning to describe the nucleation of the sp3 phase in bigraphene with misoriented layers when hydrogen atoms are deposited on its surface. For experimental misorientation angles of layers, it is shown that at small angles, nucleation is energetically favorable, that is, a gradual increase in the area with interlayer bonds with the addition of hydrogen. At the same time, at large angles, chaotic addition of hydrogen with the formation of single interlayer bonds is more likely. For small misorientation angles, structures with the maximum possible size of diamond phases were constructed. It is shown that in this case the bigraphene film turns into a polycrystal with the dominant phase of hexagonal diamond (~50%) and cubic diamond (~30%). The size of diamond grains was also determined depending on the misorientation angle of the initial bigraphene: 0.095/sin(α) nm, 0.13/sin(α) nm and 0.06/sin(α) nm for grains with surfaces (0001), (10-10) and (111), respectively. Energetically favorable diamane structures with full surface coverage of H, -OH or peroxide functional groups have been determined. The thermodynamic stability range was then determined as a function of external pressure and chemical environment depending on the choice of precursor. In particular, it was found that the use of water as a source of oxygen requires the application of pressure to form stable oxidized diamane, which is in full agreement with experimental data.