陶瓷钴蓝色料与无铅熔剂反应机理的研究

Study on Reaction Mechanism of Ceramic Cobalt-Blue Colorants and Lead Free Flux

采用固相法合成了尖晶石型CoAl2O4和硅锌矿型(Co,Zn)2SiO4陶瓷钴蓝色料,并按一定配比与无铅熔剂混合后于不同温度焙烧,采用XRD、FTIR分析技术并结合颜料的呈色与透明度等性能,对钴蓝色料与熔剂的反应机理进行了研究。结果表明,随着焙烧温度的升高,焙烧颜料中色料晶相含量迅速减少,且硅锌矿型钴蓝色料晶相减少程度更大;在高温玻璃熔体强烈的熔蚀作用下,色料晶体结构遭到破坏,由晶体着色转为离子着色,形成大量的钴蓝玻璃致使釉上钴蓝颜料耐酸性变差。

Ceramic cobalt-blue colorants of CoAl2O4 spinel and (Co,Zn)2SiO4 willemite were synthesized by solid-state reactions and the as-prepared samples were mixed with lead free flux in a proper proportion and calcined at various temperatures. Interactions between cobalt blue colorants and lead free flux were investigated by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), combined with the observation of the color and transparency of the calcined samples. The results indicate that the number of crystalline phases of both colorants, esp. the number of (Co,Zn)2SiO4 willemite, decreased dramatically with the increasing of firing temperature. Due to the strong corrosion effects of high temperature glass melt, the ceramic cobalt-blue colorants were vitrified gradually, and the main coloring mechanism is ion instead of crystal. As a result, cobalt-blue glass was formed, which is the key reason of over-glazed cobalt-blue pigments exhibiting bad acid resistance.