Structural Role of CeO2 in the Modified Borate Glass-Ceramics

Abstract

A new type of cerium borate glass-ceramic is prepared and studied. The microstructure and crystallization behaviors of the glass samples were investigated by X-ray diffraction (XRD), electron diffraction (ED), and 31P NMR spectroscopy. The microstructures of samples contain 2 are amorphous in nature. More addition of CeO2 transforms the glass to glass-ceramics without thermal annealing. The morphological change of the microstructure of these materials was followed by transmission electron microscopy (TEM). The obtained results have revealed that the addition of more than 0.8 mol% CeO2 can promote nucleation and crystallization routes that are combined with the establishment of diverse crystalline phases. Glasses with lower contents of CeO2showed no tendency to crystallization. The crystals of CeO2 containing glasses were spheroid like morphology that was assigned to the three-dimensional fast growth of the well-formed structural species in the boro-apatite phase. In addition, the cerium free glass is characterized by particle-like morphology. Then the growth of spheroid species in three-dimension plays better compatibility and bioactivity behavior than that of the other types of morphology. This is may because the spherical shape has a higher surface area than that of the needle-like morphology. Accumulation and aggregation of small-sized spheres from cerium borate phases played the role of enhancing the hardness of the studied materials.