镀镍碳纳米管对Mo_2FeB_2基金属陶瓷组织与性能的影响

Effect of nickel-plated carbon nanotubes on the microstructure and properties of Mo_2FeB_2 based cermets

采用化学镀法对碳纳米管进行表面镀镍处理,再利用真空液相烧结法制备出以镀镍碳纳米管为增强体的Mo_2FeB_2基金属陶瓷复合材料,借助SEM、EDS、硬度计等研究了添加镀镍碳纳米管对Mo_2FeB_2基金属陶瓷微观组织及力学性能的影响。结果表明,添加适量镀镍碳纳米管可细化Mo_2FeB_2基金属陶瓷组织并控制其孔洞尺寸及数量,显著提高其硬度及断裂韧性。当镀镍碳纳米管添加量为0.5%时,所得试样的晶粒最为细小,晶粒尺寸大约为1.2μm,材料的力学性能最佳,其硬度和断裂韧性分别达到1228.4HV0.3及15.90MPa·m12,相应增韧机制为裂纹偏转、桥接增韧、撕裂棱增韧和微孔洞增韧。

CNTs were coated with Ni by means of electroless plating and nickel-plated CNTs reinforced Mo_2FeB_2 based cermets were prepared by vacuum liquid-phase sintering technology.Effects of nickelplated CNTs on the microstructure and mechanical properties of Mo_2FeB_2 based cermets were investigated by SEM,EDS and hardness tester.The results show that nickel-plated CNTs can effectively refine microstructure,control size and number of pores,increase hardness and fracture toughness of cermets.The sample with 0.5% nickel-plated CNTs has the smallest grain size（1.2μm）and the best mechanical properties.Its hardness and fracture toughness reach 1228.4 HV0.3 and 15.90 MPa·m12,respectively.Crack deflection,crack bridging,tearing edge and micro pores are the main toughening factors.