Electrolytic Coloration Of Potassium Chloride Polycrystals And Mechanism Of Production And Transformation Of Color Centers

Hydroxyl-doped potassium chloride polycrystals were successfully colored electrolytically for the first time using a technique of electrolytic coloration, varied kinds of color centers were produced in the colored polycrystals. Systematical spectral measurement and analysis were carried out to the colored polycrystals. By means of measured current ~ time curves, the process and mechanism of the production of the color centers were explained further.Positions of absorption spectrum bands of OH- ions were observed in the absorption spectra of uncolored hydroxyl-doped potassium chloride polycrystals. In research, it was found that the doped OH- ions could be converted partially into U and UA color centers during preparation of polycrystals, the corresponding spectral bands were observed in the absorption spectra. In process of electrolysis, color centers were formed by the combination of OO2 ? ? Va+2- and color centers, the corresponding spectral bands were observed in K– M functions of colored hydroxyl-doped potassium chloride polycrystals. +VaA lot of V2, V3, O 2 ? ? Va+, Cu+, I-2 and F color centers were produced in hydroxyl-doped potassium chloride polycrystal after the electrolytic coloration with a pointed cathode. Because the hydroxyl-doped potassium chloride polycrystals contain a lot of OH- ions, the polycrystals cannot be colored electrolytically using the traditional electrolysis method. It is the unique anode matrix composed of the graphite grains to make the V color centers are produced firstly in the near of anode. Some V color centers were converted into F color centers under light illumination. Data of current and time were recorded in the process of electrolysis, with which current ~ time curves were plotted. After analysis, it is known that ionic motion and electron exchange between halogen ions and anode matrix composed each current zone together. Formation mechanism of current zones in current ~ time curves and closed relation between production of color center and formation of current zones were given. After varied experiments, in conclusion, a best effective coloration condition at temperature 450 oC, voltage DC 900 V and electrolysis time 90 min was found.A lot of V, Cu+, O 2 ? ? Va+, I-2 color center were produced in hydroxyl-doped potassium chloride polycrystals after electrolytic coloration with a pointed anode. Coloration mechanism of hydroxyl-doped potassium chloride polycrystals by electrolysis with a pointed anode was given, and by plotting current ~ time curves, process and mechanism of production of the color centers in colored hydroxyl - doped potassium chloride polycrystals were explained further.