Page 12 - Microsoft Word - Дисертація_Винар_end
P. 12


                  In the case of cathodic polarization due to flooding, plasticization of contact areas

                  is observed, which is manifested in the exit to the surface of the sliding strips, and,

                  despite the inhibition of anodic dissolution, an increase in material losses.

                               It was found that the mechanisms of tribocorrosion of technically pure

                  metals (aluminum, copper, iron, nickel, niobium, zirconium, titanium) by hydrogen

                  depolarization  determine  the  properties  of  secondary  structures  that  are  formed

                  during frictional interaction under the influence of hydrogen. It was recorded for

                  the  first  time  that  during  the  absorption-desorption  of  hydrogen  in  the  surface

                  layers of armco-iron there is a crystallographic reorientation of subgrains, and also

                  the distribution of maximum internal stresses changes.

                               It  is  shown  that  the  combined  action  of  flooding  and  friction

                  accelerates the diffusion processes in the amorphous nickel-phosphorus structure

                  of  the  coating,  which  promotes  the  formation  in  the  surface  layers  of  the

                  reinforcing phase of Ni3P, which increases its wear resistance. It was found that
                  the negative effect of hydrogen factor in tribocorrosion is manifested to a greater

                  extent with  increasing  hardness of  heat-treated nickel electrochemical composite
                  coatings of the Ni – B system, which is associated with reduced cohesive strength

                  between structural components of the coating due to hydrogen.
                               Chromates, which are effective corrosion inhibitors, have been found

                  to accelerate tribocorrosion of D16T alloy due to the formation of brittle secondary

                  structures. Instead, zinc phosphates increase the resistance of aluminum alloy to

                  corrosion and mechanical wear due to the formation of wear-resistant secondary

                  structures formed by mechanical and electrochemical factors.

                               It  is  established  that  in  contrast  to  classical  tribology,  during

                  tribocorrosion  processes  the  coefficient  of  friction  decreases  with  wear

                  intensification, due to changes in surface properties under the action of hydrogen

                  and corrosion factors and the formation of secondary structures.
   7   8   9   10   11   12   13   14   15   16   17