EFFECTS OF Nd2O3 ON THE CRYSTALLIZATION AND PROPERTIES OF GLASS CERAMIC IN Li2O–K2O–Al2O3–SiO2–P2O5 SYSTEM

Abstract

Glass ceramics (GCs), which often contain a small amount of rare earth oxides to improve their performance, are ideal for dental restorative applications. The aim of this study was to investigate the various effects of Nd 2 O 3 content (0-1 wt%) on crystallization and properties of GC derived from Li 2 O-K 2 O-Al 2 O 3 -SiO 2 -P 2 O 5 system. The glass blocks were formed from the molten at 1450 °C. Based on the DTA results, the glass samples were experienced by two-stage heat-treatment (600 °C/ 90 min + 720 °C/ 30 min) to change to ingots. After that, the ingot samples were fired in a hot pressing furnace EP3000 at 930 °C for 30 min. The results of powder X-ray diffraction (XRD) indicated that the final GCs contained crystals such as lithium disilicate (Li 2 Si 2 O 5 or LS 2 ), lithium metasilicate (Li 2 SiO 3 or LS) and the traces of lithium phosphate (Li 3 PO 4 ). With increasing Nd 2 O 3 content, the relative amount of LS phase increased slightly while LS 2 phase decreased. However, the final GC containing 0.75 wt% Nd 2 O 3 had the highest bending strength at 293 MPa, the lowest chemical solubility and relative high Vicker hardness. These samples had a high degree of crystallization and the highest relative content of desired LS 2 phase.