Hadian A.m., Abu Fanas S.h.,
Volume 2, Issue 4 (12-2005)
Abstract
Enhancing the properties of dental resin composites is of interest to researchers. The objective of the present investigation was to improve the strength and fracture toughness of dental composites via addition of silicon carbide whiskers and substitution of commonly used filler materials with stabilized zirconia ceramic powder. It was also intended to study the effect of powder- to- whisker ratio on mechanical properties of the resultant composites. The flexural strength and fracture toughness of composite samples with different whiskers loadings were measured. It was found that addition of whiskers to the composites enhances the mechanical properties of the composites. The strength and fracture toughness increased by increasing the amount of whiskers. The flexural strength of a composite having 60wt% whisker and 10wt% zirconia powder was about 210 MPa while that of the composite having only 60wt% ceramic powder was about 110 MPa. The microstructural examinations revealed that reinforcing mechanism was whiskers pull-out as well as crack deflection.
Zahra Zalnezhad, Morteza Sasani Ghamsari, Hamid Haratizadeh,
Volume 21, Issue 0 (3-2024)
Abstract
Silicon carbide (SiC) is one of the most important silicon-based compounds, owing to its favorable physical, chemical, and biological properties, and is widely employed in various fields such as electronics, chemical industries, and quantum computing. Several methods have been reported for synthesizing SiC nanoparticles, including chemical vapor deposition (CVD), hydrothermal synthesis, carbothermal reduction, and sol–gel processing. Among these, the sol–gel method has attracted significant attention due to its high yield, process controllability, biocompatibility, accessibility of precursors, and ability to produce nanoparticles. In this study, SiC nanosized powders were synthesized through the sol–gel route combined with carbothermal reduction, using tetraethyl orthosilicate (C2H5)4SiO4) and sucrose (C11H22O11) as the silicon and carbon sources, respectively. The silica/sucrose composite was subjected to carbothermal reduction under an argon atmosphere at a pressure of 10 mTorr in a vacuum furnace at 1350°C for 3 h. The structural properties of the synthesized SiC nanopowders were analyzed using X-ray diffraction (XRD), while their optical characteristics were investigated through FTIR, diffuse reflectance spectroscopy (DRS), and photoluminescence (PL). This work demonstrates a greener, lower-temperature route to phase-controlled SiC nanoparticles with optically active vacancy centers.
