Effect of Boron Nitride Nanosheets Addition on Structure and Properties of Spark Plasma Sintering Sintered B4C Ceramics
Boron nitride nanosheets(BNNSs)were used as additives to prepare boron carbide(B4C)ceramics by spark plasma sintering(SPS)at 1 750 ℃.The effect of BNNSs on the microstructure and mechanical properties of B4C ceramics was studied in detail.Research has shown that the added BNNSs are uniformly distributed at the grain bound-aries of B4C,which improves the density of B4C and has a certain inhibitory effect on the growth of boron carbide grains.The mechanical properties of B4C ceramics increase with the addition of BNNSs.When the addition of BNNSs is 3％,the comprehensive performance of the composite ceramics reaches its best,with bending strength and fracture toughness of 654 MPa and 4.857 MPa·m1 2.respectively.Analysis suggests that the connection between BNNSs and B4C is a weak interfacial bonding.When the ceramic is subjected to force,the fracture mode changes from transgranular fracture to transgranular intergranular mixed fracture.
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