Preparation and characterization of BAS reinforced with SiC platelets

BAS glass-ceramic powders were prepared by sol-gel processing. SiC platelets reinforced BAS glass-ceramic matrix composites with high density and uniform microstructure could be made using hot-pressing method. The related processing parameters were studied, including effects of additional seed on transformation from H to M of barium aluminosilicate. DTA method was used to determine exact time to press mixture powders during hot-pressing for the purpose of effective densification. Microstructure and mechanical properties of the composites were investigated by mean of SEM, XRD and TEM techniques as well as three points bending test and single edge notched beam measurement. The results show that the flexural strength and fracture toughness value of the BAS glass-ceramic matrix composites can be effectively improved by the addition of the SiC platelets. But the relative densities of composites are slightly decreased. The main toughening mechanism is crack deflection, platelets pull-out and bridging. The increased value of flexural strength is contributed to the load transition effect from matrix to SiC platelets.