Investigation Of Coloration Mechanism On Sulfoselenide Cadmium Doped Canasite Glass-ceramics

The glass-ceramic decorative materials, which has excellent physical and chemical properties that can not be compared with the natural stone, is a new and advanced building decoration materials, attracting increasing attention and having a broad application prospects in the future.However, the glass-ceramic coloration mechanism is not clear at present. There are big differences in the coloration mechanism between glass-ceramic and ordinary glass, it is not applicable to use the coloration theory of ordinary glass to guide the production of the colored glass-ceramic, so it is of great significance to develop the new glass-ceramic coloration mechanism to guide the production of colored glass-ceramic, in the meantime, it will accelerate the research of the coloration mechanism of colored glass-ceramic. The R2O-CaO-SiO2 glass-ceramic having high values of flexural strength and fracture toughness, which can be produced by continuously rolling process, is the high-grade decorative materials.In this paper, R2O-CaO-SiO2 glass-ceramic was choose as the research object, our research is focused on the investigation of the coloration mechanism of R2O-CaO-SiO2 glass-ceramics doped with the colorants of CdS and Se.A series of the colored glass-ceramic with different CdS/Se ratio were prepared by traditional melt quenching technology, The influence of heat treatment, different CdS/Se ratio and melting atmosphere on crystallization properties and color of the colored R2O-CaO-SiO2 glass-ceramics was investigated by XRD, EDS, FE-SEM and UV-visible spectrophotometer.The results indicate that:1.The weak reducing atmosphere is more suitable melting condition for preparing sulfoselenide cadmium colored glass-ceramic, which is achieved by adding 1% Zn in the experiment, at the same time,4% ZnO was also added to inhibit the volatilization of CdS and Se.2.The main crystal phases in the R2O-CaO-SiO2 colored glass-ceramic were radial canasite (K2Na4Ca5Si12O30F4) and a-canasite (K3Na3Ca5[Si12O30]F3 (OH) 1H2O). 3.As the Se/CdS ratio increase, the glasses are almost colorless or pale color before heat treatment, but they change to orange or orange red after nuclearation and crystallization heat treatment, which is obviously different from the parent glass. However, the color of the glass-ceramics changes from yellow to orange and then to red after isothermal heat treatment (600～800℃), and the cut-off wavelength shifts to longer wavelength in the visible spectrum.4.When Se/CdS ratio is 0.55,the red glass-ceramic can be get under the heat treatment temperature of 800℃holding for 2 hours;When the Se/CdS ratio is constant, the color of the glass-ceramics changes from yellow to orange and to red with the heat treatment temperature increases;and when the heat treatment temperature is constant, the color of the glass-ceramics gradually deepened with the heat treatment time lengthened. The color of the glass-ceramic was more obviously affected by heat treatment temperature than the heat treatment time.5.The coloring agent elements Cd, S and Se evenly distributed in the glass-ceramic, which can be observed by FE-SEM surface scanning.