SiC Partikul Boyutunun Yerinde Sentezleme Yontemi ile Uretilen HfB2 SiC Kompozitlerinin Mikroyapisal, Mekanik ve Oksidasyon Ozellikleri Uzerine Etkisi
In situ synthesis and densification of hafnium diboride silicon carbide (HfB2 SiC) ceramic composites were studied by the spark plasma sintering (SPS) method using HfO2, B, and SiC as starting powders. Influence of SiC particle size ~2 mm and ~10 mm) on mechanical properties and oxidation resistance of in situ composites were extensively investigated. According to the achieved results, the highest densification ~95 TD) was obtained with fine SiC particle reinforcement. The measured Vickers hardness and fracture toughness of the composites containing fine SiC were 14.3 GPa and 5.42 MPa.m, respectively. The fracture mode changed from transgranular cleavage to a mixed mode, and the crack deflection was believed to be the primary toughening mechanism. From oxidation test result, the composite with fine SiC particles exhibited more inhomogeneous oxide scales compared to that of coarse SiC containing composite.