Solid-phase reactions, self-propagating high-temperature synthesis, and martensitic transformations in thin films

Solid-state synthesis and phase transformations in Ni/Fe films: Structural and magnetic studies

“…Indeed, the Ni-Fe phase diagram in the invar region shows the only one phase transition at T 1 K ¼ 618 K. This transition is believed to be the eutectoid decomposition of ferromagnetic phase: g fer 2a-Fe+FeNi 3 [1,2]. Probably the eutectoid decomposition g fer -a-Fe+FeNi 3 is the reverse reaction for reaction (4) started at T 2 0 $720 K. According to the phase diagram there are no structural transformations in the invar region for the temperature above 618 K. However, the results of our previous works [68][69][70][71][72][73] justify the existence of two more the solid-state transformations at temperatures T 0 2 and T 0 3 , which correspond to reactions (4) and (5). The new Fe-Ni phase diagram [1,2] involves the monotectoid decomposition of paramagnetic FCC austenite into BCC ferrite and ferromagnetic FCC austenite at about 400 1C.…”

“…The g(Fe,Ni) phase arises as a product of a-Fe+NiFe-g(Fe,Ni) reaction with the temperature increasing above T 0 3 , and the g(Fe,Ni) phase decomposes to the NiFe and g par phases when the temperature decreases below T 0 3 : g(Fe,Ni)-NiFe+g par . The other possible assumption is the following: the g par phase initiation temperature T 0 3 coincides with the A S temperature of the reverse MT a 0 -g par , as it was observed at the solid-state synthesis in Ni/Ti [70], Au/Cd [71] and Al/Ni [72] films. As mentioned above, reactions (4) and (5) are reversible and, therefore, they are connected with the reversible structural solid-state transformations.…”

“…Recently, we have shown that the initiation temperature T i 0 for the film bilayer systems coincide with the structural phase transition temperature T K for the given binary system [68][69][70][71][72][73]. On the basis of the above mentioned assumption, we will consider possible phase transformations in a Ni-Fe system witch are connected with solid-state reactions (3), (4) and (5).…”

The γ-Fe formation in epitaxial Cu(001)/Fe(001) thin films by the solid-state synthesis: Structural and magnetic features

“…Also, it must be noted that the g-Fe formation starts after annealing at the temperature T 0 ¼ 850 1C which is consistent with an eutectoid temperature of the Fe-Cu system. Recently we have shown that intermixing of layers and the formation of compounds (solid-state synthesis) in thin-film systems and multilayers begin at a minimum temperature of a structural phase transformation in a given binary system [28][29][30][31][32][33]. In the Fe-Cu system, such a transformation is the eutectoid transformation with a temperature of 850 1C [34].…”

“…Scenarios and mechanisms of phase layering in the Fe-Cu systems still remain poorly determined. Our previous results showed that the mass transport and formation of compounds in bilayers and multilayers start at minimum temperature of a solid-state transformation in a given binary system [28][29][30][31][32][33]. In the Fe-Cu system, the only eutectoid transformation with a temperature of 850 1C takes place [34].…”