[Study on microstructure of jadeite melt and its glass].

ABSTRACT

Comprehensive experimental as well as theoretical methods were applied to investigate the structure evolution of jadeite in the hot-melt process, especially on the variation of aluminium coordination number. In-situ high temperature Raman spectroscopic technique was used to record the characteristic Raman spectra of jadeite and its melt with the increasing temperature, consequently, density function theory and ab initio calculation methods were applied to analyze the related micro-structures and aluminium coordination number and simulate the Raman spectra. Results showed that aluminum in jadeite crystal is all six-fold and would transform into four-fold coordination at 1 293K while jadeite being melting. Aluminum is prominently in four-fold coordination in the melt, in which TO4 (T = Si, Al) connects to each other as the network of multiple rings. Five-fold coordinated aluminum emerges and it appears the trend of phase separation while the melt transformed into glass by the processing of fast cooling.