Experimental and theoretical study on the effect of different rare-earth oxides on the high-temperature stability of SiO2 glass at 1973K

摘要

The effect of different rare-earth oxides additives (La2O3, Nd2O3, Y2O3, Sm2O3, Yb2O3 and Lu2O3) on the stability of SiO2 glass at 1973 K was systematically studied employing volatility test and first-principles calculations. Both experimental and theoretical results show that the introduction of rare-earth oxides plays an active role in developing the stability of SiO2 glass at 1973 K due to the presence of Re2Si2O7 (Re= La, Nd, Y, Sm, Yb, Lu) phase. SiO2 glass samples doped with rare-earth oxide owning smaller cationic radius show better stability at 1973 K. Re atoms in Re2Si2O7 can diffuse into SiO2, which tends to occupy the interstitial site of SiO2 network. The influence of various interstitial Re atoms on SiO2 network are different and the inLu-SiO2 structure is the most stable. Meanwhile, the diffusion of Re atoms enhances the interface bonding between SiO2 (0 1 0) and in ReSiO2 (1 1 2) and the inLu-SiO2 (1 1 2)/SiO2 (0 1 0) interface owns the highest binding energy, which is profitable to develop the thermal stability of SiO2 glass at 1973 K.