Structural state of xerogels based on water glass modified by cobalt, nickel, and titanium

Results of the X-ray study of the atomic structure of xerogels based on water glass (WG) modified by nickel, cobalt, and titanium are presented. The original xerogel sample was obtained from a standard sodium water glass during dehydration to constant weight at 200 °C. An aqueous solution of alkali silicate was a standard sodium water glass (WG, state standard 13078, silicate modulus n = 2,9 ± 0,1, density p = 1,45 g/cm 3). The WG-Co, WG-Ni and WG-Ti compositions were obtained by the combination of the modifier and the aqueous solution of WG during further dehydration to constant weight at 200 °C. Experimental results were processed with the use of Warren - Finbak method: using pair function curves D(r) radii of coordination spheres and coordination numbers were calculated for all of the investigated samples. The obtained short-range order characteristics can be used to generate computer models of the studied xerogels with spatial arrangement of atoms. Analysis of the short-range order characteristics showed that the silicon-oxygen tetrahedra are saved in WG modified by Co, Ni and Ti. In these systems, the short-range order is similar to the atomic arrangement in crystalline phases of comparable composition, but the mutual orientation of the coordination polyhedra in space is different.