International Journal of Applied Ceramic Technology · 2009 · 64 citations · 27 references
Natural SciencesMaterials EngineeringMaterials ScienceCeramic MaterialsCeramicsMechanical Behavior Of MaterialsCeramic CompositesCeramic Matrix CompositesComposite MaterialsPowder ProcessingPowder TechnologyStructural CeramicsCeramic Fracture BehaviorCeramic SynthesisFlexural StrengthFracture BehaviorHot Pressing Of Ceramic CompositesMaterial Fracture BehaviorMechanical Properties Of Ceramic CompositesSilicon Carbide (Sic) Materials
Phase pure hafnium diboride (HfB 2 ) powder was synthesized by borothermal reduction of hafnium dioxide using amorphous boron at relatively low temperature (1600°C) in vacuum. The synthesized HfB 2 powder had an average particle size of 1.37 μm with an equiaxed shape, and a low oxygen content of 0.79 wt%. Using the as‐synthesized HfB 2 powder and a commercial SiC, HfB 2 monolithic, and HfB 2 –20 vol%SiC composite were hot pressed at 2000°C to relative densities of 95.7% and 99.2%, respectively. With the addition of SiC, the grain size decreased and the fracture behavior changed from intergranular to a mixed mode, which resulted in a high flexural strength of 993±90 MPa for the composite. Fracture toughness of the composite was 6.29±0.65 MPa m 1/2 , which was significantly higher than that of the HfB 2 monolithic and the reported values in literature.
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