【摘要】 三元硼化物因其具有高硬度、低密度、高耐磨性、高耐腐蚀性等特征被广泛应用在耐磨、耐腐蚀领域,但是其综合力学性能与WC-Co硬质合金相比仍有差距。本文研究添加第二相TiB₂颗粒对1 300℃烧结原位反应MoCoB-Co金属陶瓷微观组织及力学性能的影响。结果表明:添加TiB₂后原位合成的MoCoB和TiB₂晶粒构成MoCoB-Co金属陶瓷的双硬质相,MoCoB晶粒得到明显细化,MoCoB呈现等轴状与棒状两种形貌;随着TiB₂含量的增加,MoCoB/Co的含量比逐步增加,等轴状MoCoB的尺寸基本保持为1～2μm,棒状MoCoB在添加15%～20%质量分数的TiB₂时略有长大,短轴增加较明显。TiB₂作为第二硬质相增强基体,硬度明显提高,当TiB₂质量分数为15%时硬度为HRA 88.9,较未添加时提高约6%。更多还原

【Abstract】 Ternary borides have been widely used due to high hardness,low density,high wear resistance and high corrosion resistance.However,the ternary borides based cermets have lower mechanical properties when compared with WC-Co cemented carbide.The effects of TiB₂ particle additions on microstructure and mechanical properties of MoCoB-Co cermets sintered at 1 300 ℃ were investigated.The in-situ MoCoB and TiB₂ are the double hard phases of MoCoB-Co cermet.The MoCoB grains,which exhibitboth equiaxed and rod morphologies,are obviously refined.The ratio of MoCoB/Co gradually increases with the increase of TiB₂ content,but the grain size of equiaxed MoCoB remains 1～2 μm.When the content of TiB₂ is 15%～20%（mass fraction,the samebelow）,the rod MoCoB grows and the minoraxisincreases significantly.The hardness of the cermet is improved with TiB₂ addition.When the TiB₂ content is 15%,the hardness reaches HRA 88.9,which is about 6% higher than that without addition.更多还原