摘要 : This article presents the results of an experimental study of the influence of different factors on the structure and extent of the hydration boundary layers (BL) of oxidised synthetic diamond (OSD) and oxidised graphite (OG). The... 展开 This article presents the results of an experimental study of the influence of different factors on the structure and extent of the hydration boundary layers (BL) of oxidised synthetic diamond (OSD) and oxidised graphite (OG). The experimental technique allows changes in the hydrodynamically immobile BL thickness to be recorded by means of an electrokinetic method. It also provides independent information about the surface charge (#sigma#), #zeta# potential and sol stability over a wide range of pH and concentration of the inert electrolyte (KCl). To check the correctness and the reliability of the technique we studied the influence of the four different factors on the BL thickness: (1) hydrophilization of the graphite and diamond surface (by means of an increase in the degree of oxidation); (2) preliminary thermotreatment of the OSD micropowder in an inert gas flow or in a vacuum; (3) introduction into aqueous dispersions of OSD and OG of the non-ionogenic compounds, promoting the destruction of the BL structure; (4)influence of temperature on the electrophoretic mobility and the dispersion stability. On the basis of the influence of each of these factors on the BL, it is established that the sign of the #zeta# potential change correlates strictly with the direction of the shift in the slip-plane boundary, supporting the basic concept of the method. On the basis of the dependences obtained, #zeta#(C_(el)) for constant #sigma#(pH), and #zeta#(#sigma#) for constant ionic strength, we estimated the thickness h of the hydrodynamically immobile hydration layer on the surfaces of OSD and OG, applying the diffuse double electric layer theory. Using the different approaches we found that h varied in the range h = 1.0 -3.0 nm. The values obtained for h on average correspond to the BL thickness of 5-7 molecular water layers. These results are in quatitative agreement with experimental data on the stability of the disperisions under consideration and with the results of a calculation of the pair interaction potential curves for OSD and OG particles in the framework of the genealised DLVO theory taking into account the structural forces. 收起