Mo涂层的立方氮化硼（cBN）与玻化陶瓷复合烧结体的研究

Study on Composite Materials Sintered by Mo Clad cBN and Vitrified Ceramics

本文用ＤＴＡ、ＸＲＤ、ＳＥＭ、ＥＰＭＡ等研究了Ｍｏ镀层与立方氮化硼（ＣＢＮ）晶体在６００～１０００℃温度范围的界面反应过程，以及界面成分、结构特征；讨论了Ｍｏ镀层在烧结时与ＳｉＯ２－Ｎａ２Ｏ－Ｂ２Ｏ３玻化结合剂的作用。结果表明，Ｍｏ镀层与ｃＢＮ晶体在７００℃以上形成ＭＯ２Ｎ，在８００℃以上形成Ｍｏ２Ｂ５和ＭｏＢ。这些在ｃＢＮ晶体表面外延生长的难熔化合物，使Ｍｏ镀层与ｃＢＮ牢固结合，并阻止了结合剂中碱性组分对ｃＢＮ的侵蚀，实现了ｃＢＮ与结合剂间的强力化学键合。

Interface composition, structure and bond properties between Mo clad cBN and vitrified ceramics are inverstigated by DTA, XRD, SEM and EPMA. Test results show that interface reaction between Mo-clading and cBN occur at above700℃,the epitaxial Mo2N and MoB+Mo2B5 are formed on the cBN surface above 700℃and 800℃separately.The bending strength of composite materials sintered at 900℃for 2h are increased from41.90MPa without clad cBN to 50.30MPa with Mo clad cBN, remaining cBN in sintered composite materials are increased from 67vol% without clad cBN to 100 vol % with Mo clad cBN,thus these Mo-clading and epitaxial compound films grown on surface of cBN improve the bond between thecBN grit and the bonder,prevent cBN grit from corrosion during sitering.