Effect of Modifying Dopes on the Mechanical Properties of Epoxy Coatings Affected by Thermocycling

Instrumented indentation is used to study the surface mechanical properties (hardness, elastic modulus, and creep) of pure epoxy lacquer and a lacquer modified with TiO2, SiO2, and ZnO. Changes in the mechanical characteristics of the coated and thermocycled materials are evaluated. The dopes are shown to affect the mechanical characteristics manifesting themselves in the varying values of the elastic modulus and hardness. Cyclic thermal action decreases the values of the elastic modulus and hardness of the pure epoxy lacquer and the lacquers doped with SiO2 and ZnO, but it has an ambiguous effect on these values for the TiO2-doped lacquer. Obviously, it is mostly the polymer base that is responsible for the creep of the loaded coatings; therefore, the dopes have no significant effect on the behavior of the time dependence of creep, but they decrease its value.