Effect of Composition on Crystallization of YYb-Si-Al-O-N B-Phase Glasses

The effect of a partial or full replacement of yttrium by ytterbium on the crystallization of an oxynitride B-phase parent glass with composition (eo) 35YYb:45Si:20Al:83O:17N has been investigated by thermal analysis, X-ray diffractometry and analytical transmission electron microscopy. Single B-phase formation was extended to higher temperatures by low ytterbium:yttrium ratios, while a full replacement resulted in a two-phase B- and J-phase glass-ceramic. The B-phase crystals took up a substantial range of composition that was dependent on the substitution level, and yttriumytterbium was always clearly anti-correlated with silicon. Some aluminum was accommodated in the dendritic J-phase crystals, and their yttriumytterbium content varied between 64 and 79 cation%.