Effects of Nd Content on Structure and Chemical Durability of Zirconolite–Barium Borosilicate Glass‐Ceramics

Abstract

The effects of Nd2O3 content (0–12 wt %) on crystalline phases, microstructure, and chemical durability of barium borosilicate glass‐ceramics belonging to SiO2–B2O3–Na2O–BaO–CaO–TiO2–ZrO2–Nd2O3 system were studied. The results show that the glass‐ceramics with 2–6 wt% of Nd2O3 possess mainly zirconolite and titanite phases along with a small amount baddeleyite phase in the bulk. Calcium titanate appears when the Nd2O3 content increases to 8 wt%, and the amount of quadrate calcium titanate crystals increases with further increasing content of Nd2O3. For the glass‐ceramics with 6 wt% Nd2O3 (Nd‐6), Nd elements homogeneously distribute in zirconolite, titanite, and residual glass phases. There is a strong enrichment of Nd in calcium titanate crystals for the sample with 10 wt% Nd2O3. The viscosity of Nd‐6 glass is about 49 dPa·s at 1150°C. Moreover, Nd‐6 glass‐ceramics show the lower normalized leaching rates of B (LRB), Ca (LRCa), and Nd (LRNd) when compared to that of the sample with 8 wt% Nd2O3. After 42 days, LRB, LRCa, and LRNd of the Nd‐6 glass‐ceramics are about 6.8 × 10−3, 1.6 × 10−3, and 4.4 × 10−6 g·m−2·d−1, respectively.