锆镨黄固相合成过程中镨的赋存状态研究

Research on Occurrence State of Praseodymium in the Solid Phase Synthesis of Pr-doped Zircon Pigments

研究采用XRD、SEM和MLA等技术对不同煅烧温度和冷却条件下利用固态合成法合成的锆镨黄陶瓷色料进行了表征。研究结果表明,在合成温度为900℃和急冷条件下合成的锆镨黄色料晶粒较细,黄度值高。镨的赋存状态表明,锆镨黄的色度与ZrSiO_(4)含量和镨的赋存状态有明显关系,当煅烧温度为900℃时,合成的ZrSiO_(4)量达到最大,镨在ZrSiO_(4)中占有率达到最大,超过三分之二,其黄度值也达到最大。不同温度下合成的色料样品中氧化锆中镨含量远低于同时期合成的ZrSiO_(4)中镨含量,同时在这些样品均检测出Na_(2)Pr_(8)(SiO_(4))_(6)F_(2)等镨的硅酸盐化合物,而该类化合物大部分已单体晶簇形式存在,表明镨元素在合成初期并未扩散到氧化锆中,而主要以气态形式存在,因此锆镨黄的合成属于气-固反应。

Pr-doped zircon pigments by solid-phase synthesis were characterized by XRD,SEM and MLA under different calcination temperatures and cooling conditions.The results show that Pr-doped zircon pigments synthesized at 900℃has fine grains and high yellowness value.The occurrence state of praseodymium shows that the chromaticity of Pr-doped zircon pigments is obviously related to ZrSiO_(4)content and praseodymium occurrence state.When the calcination temperature is 900℃,the amount of synthesized ZrSiO_(4)reaches the maximum,the proportion of praseodymium in ZrSiO_(4)reaches the maximum,more than two thirds,and its yellowness value also reaches the maximum.The praseodymium content of zirconia in pigment samples synthesized at different temperatures is much lower than that of ZrSiO_(4)synthesized at the same time.Meanwhile,praseodymium silicate compounds such as Na_(2)Pr_(8)(SiO_(4))_(6)F_(2)are detected in these samples,and most of these compounds exist in the form of monomer crystal clusters,indicating that praseodymium does not diffuse into zirconia at the initial stage of synthesis,but mainly exists in gaseous form.Therefore,the synthesis of Pr-doped zircon pigments belongs to gas-solid reaction.