Nanocomposites and nanomaterials

Transformation of the epoxy-polysiloxane nanocomposite structure under the action of high shear stresses
Havrylova V.S.1, Zhyltsova S.V.2, Pashchenko E.O.1, Babkina N.V.3, Hryhorenko T.I., Tkach V.M.1
1 V. Bakul Institute for Superhard Materials of the NAS of Ukraine, 2, Avtozavodskaya Str., Kyiv-04074, Ukraine
E-mail: vsgavrilova@gmail.com
2 Vasyl’ Stus Donetsk National University, vul. 600-richchia, 21, Vinnytsia-21021, Ukraine
3 Institute of Macromolecular Chemistry of the NAS of Ukraine, 48, Kharkivske Shosse, Kyiv-02160, Ukraine

According to data obtained by transmission and scanning electron microscopy, a significant change in the epoxy polymer structure occurs upon the addition of the polysiloxane particles (PSPs) and graphite. The initial epoxy polymer has a homogeneous single-phase structure. Addition of PSPs causes the formation of areas with pronounced layer morphology, and the addition of graphite leads to a further reduction in the grains of the epoxy matrix and the formation of a heterophase layer structure with a uniform phase distribution, which significantly improves the deformation-strength and adhesion properties of the composite.
Under the action of large shear stresses during plastic deformation, the structure of the coating of the indicated composite undergoes cardinal changes. Associated fine grains of 100–200 nm in size are formed. The boundaries between them are continuous well-defined. Thus, due to the plastic deformation of the coating, fragmentation of its grains takes place. The formation of such a structure contributes to the enhancement of the strength characteristics of the coating.
The use of this composite as an antifriction solid lubricant for cold plastic deformation of titanium alloys made it possible to carry out a multi-cycle deforming stretching of parts from the alloys VT1-0, VT22 and VT6 at contact pressures up to 3.2 GPa.