摘要
山东蓝宝石颜色深暗,与其主要致色元素有着直接关系。对其化学成分进行分析认为:Cr2O3是红色、橙黄色、黄色的主要致色因素。而w(TiO2)低,w(TFeO)高,尤其是Fe3+大于全铁的90%,TFeO/TiO2比值大是山东蓝宝石颜色深暗的主要原因。对其紫外-可见光-近红外吸收光谱进行分析,进一步得出Cr3+离子的d-d电子跃迁、成对Fe3+离子、单Fe3+离子的d-d电子跃迁、Fe2+-Ti4+之间的电荷转移、Fe2+-Fe3+之间的电荷转移等是山东蓝宝石致色的本质。代表绝大多数山东蓝宝石颜色的深蓝色蓝宝石,缺失紫外-可见光-近红外吸收光谱的575~711 nm吸收带,即缺少Fe2+-Ti4+之间的电荷转移。因此,针对性地选择w(TiO2)高的蓝宝石进行改善,或是设法加入TiO2、减少Fe3+含量、在还原条件下改变其TFeO/TiO2的比值,应是目前山东蓝宝石改色的关键。
The main color-causing elements are the major factors that make the dark color of sapphires in Shandong province. By the analysis of chemical compositions obtained from electron microprobe are as follows: Cr2O3 for red, orange and yellow; the low TiO2,high content of TFeO, especially Fe^3+〉90% of TFeO, and big ratio of TFeO/TiO2, are the main factors that make the dark color of the sapphires. By the study of ultraviolet visible-near infrared absorption spectrum sketch, it is further concluded that Cr^3+ d-d jump electron,Fe^3+ coupling effect, Fe^3+ d-d jump electron, charge transfer of Fe^2+-Ti^4+, and charge transfer of Fe^2+-Fe^3+ are the main factor for coloring of the sapphairs. The popular dark blue sapphires in Shandong province lack 575- 711nm absorption spectrum band of ultraviolet-visible-near infrared region,namely no Fe^2+-Ti^4+ charge transfer. Therefore, the most important for changing colors of the sapphires is to select sapphires with high TiO2 and lower the content of Fe^3+, add TiO2 and reduce the ratio of TFeO/TiO2 under reductive condition.
出处
《地质找矿论丛》
CAS
CSCD
2006年第2期115-119,共5页
Contributions to Geology and Mineral Resources Research
基金
国家教育部博士点基金(1999014513)资助