Influence of Al۲O۳ Additive on Mechanical Properties of Wollastonite Glass-Ceramics

In this paper, wollastonite glass-ceramics and composites of wollastonite glass– ceramics with ۲.۵, ۵, ۱۰ and ۲۰ weight percent alumina with an average size of ۲ microns and also wollastonite glass-ceramics with ۲.۵, ۵, and ۱۰ percent alumina with an average size of ۴۰ nanometers were produced without pressure by Sintering and their physical properties (e.g. bulky density, the percentage of linear shrinkage and relative density) were measured. Sinter operation in the temperature range of ۱۰۳۰-۱۱۷۰ °С was performed for ۳ hours. Existing phases in composites by X-ray Diffraction (XRD) and their structure were examined by Scanning Electron Microscopy (SEM) and while measuring mechanical properties of composites such as flexural strength, hardness and compared fracture toughness with base glass ceramic was performed. Results indicate that adding ۲.۵ percent micron-sized alumina to wollastonite glass-ceramics decreases the flexural strength from ۸.۰۱±۱۲۰ to ۱۰.۲۶±۵۰ MPa and its fracture toughness declines to ۰.۸±۰.۷۴, while by adding ۲.۵ percent nano-alumina to wollastonite glass – ceramics, the flexural strength increases from ۸.۰۱±۱۲۰ to ۲۰.۷±۱۳۳ MPa and its fracture toughness improves up to ۱.۴۰±۱۰.

Keywords:

Glass-Ceramic Composite , Nano-Alumina , Mechanical Properties , Sintering , Thermal properties , Wollastonite