BN纳米片添加对放电等离子烧结B_(4)C陶瓷结构与性能的影响

Effect of Boron Nitride Nanosheets Addition on Structure and Properties of Spark Plasma Sintering Sintered B_(4)C Ceramics

以氮化硼纳米片(Boron Nitride Nanosheets,BNNSs)为添加剂,通过放电等离子烧结技术(Spark Plasma Sintering,SPS)在1750℃烧结制备了碳化硼(B_(4)C)陶瓷,重点研究了BNNSs对B_(4)C陶瓷微观结构与力学性能的影响。研究表明,添加的BNNSs均匀分布在B_(4)C晶粒晶界处,提高B_(4)C的致密度的同时,对碳化硼晶粒的生长有一定的抑制作用。B_(4)C陶瓷的力学性能随着BNNSs添加量的增加而提高,当BNNSs的质量分数为3%时,B_(4)C陶瓷的综合性能达到最佳,其抗弯强度和断裂韧性分别为654 MPa、4.857 MPa·m 1/2。分析认为,BNNSs与B_(4)C的连接为弱界面结合,当陶瓷受力时,断裂模式从穿晶断裂变为穿晶-沿晶混合断裂。

Boron nitride nanosheets(BNNSs)were used as additives to prepare boron carbide(B_(4)C)ceramics by spark plasma sintering(SPS)at 1750℃.The effect of BNNSs on the microstructure and mechanical properties of B_(4)C ceramics was studied in detail.Research has shown that the added BNNSs are uniformly distributed at the grain boundaries of B_(4)C,which improves the density of B_(4)C and has a certain inhibitory effect on the growth of boron carbide grains.The mechanical properties of B_(4)C 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·m^(1/2),respectively.Analysis suggests that the connection between BNNSs and B_(4)C is a weak interfacial bonding.When the ceramic is subjected to force,the fracture mode changes from transgranular fracture to transgranular intergranular mixed fracture.