ABSTRACT
The process starts with the preparation of polymer solutions, for instance, polyvinyl alcohol (PVA), and metal compounds, for instance, 3dmetal chlorides. Afterwards, the solutions with a certain concentration are mixed in the ratio “PVA-metal chloride” equals to 20:1-1:5. Then the prepared solutions are dried till they obtain gel-like colored films with further temperature elevation up to 100˚C. The color changes depending upon the metal. The films obtained are controlled spectrophotometrically, and also with the help of transmission optical microscopy and atomic force microscopy. When the film color changes to black, the films are heated in the furnace according to the following program: 100-200-300-400˚C. As a result, the dark porous semiproduct with many microcracks is formed, that is milled in spherical or jet mill. The nanopowder obtained is steamed and dispersed in hot water. After filtration, the powder is dried and tested by means of Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and electron microdiffraction.
