Formation of Sr 2 Si 5 N 8 :Eu 2+ and Its Transformation to SrSi 6 N 8 :Eu 2+ Controlled by Temperature and Gas Pressure

• Published in: Journal of the American Ceramic Society 2015-08, Vol.98 (8), p.2662-2669
• Main Authors: Wu, Shin‐Mou, Hung, Hao‐En, Hsieh, Chi‐Hsing, Lin, Yin‐Chih, Wang, Li‐Chun, Tsai, Yi‐Ting, Lin, Chun Che, Liu, Ru‐Shi
• Format: Article
• Language: English
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.13646

Firing temperature and gas pressure effect of synthesizing Sr 2 Si 5 N 8 :Eu 2+ were investigated. The emission intensity is positively correlated with the firing temperature under 0.1 and 0.5 MPa gas pressure. The Sr 2 Si 5 N 8 :Eu 2+ with the highest emission intensity was found at 1700°C and 1980°C under 0.1 and 0.5 MPa gas pressure, respectively. Although the maximum emission intensity of Sr 2 Si 5 N 8 :Eu 2+ obtained under 0.5 MPa gas pressure condition is higher than that under 0.1 MPa. The Sr 2 Si 5 N 8 :Eu 2+ synthesized under 0.5 MPa gas pressure in the temperature range from 1600°C to 1800°C have lower emission intensities than that synthesized under 0.1 MPa indicating that the melting of Sr 3 N 2 is an important step for the formation of Sr 2 Si 5 N 8 :Eu 2+ . Moreover, the Sr 2 Si 5 N 8 :Eu 2+ undergoes phase transition into SrSi 6 N 8 :Eu 2+ completely after elongating the heating duration to 6 h at 1980°C under 0.5 MPa gas pressure. The same feature was observed under 0.1 MPa gas pressure after firing 8 h at 1750°C. Different heating durations led to different degrees of phase transition.