Development And Application Of Cutting Tool With The Incorporation Of Graphene Oxide Self-assembly Coated Si₃N₄ Powders

Al₂O₃-based ceramic composites are widely used as tool materials due to their high hardness,wear resistance,corrosion resistance and high temperature resistance.However,the poor toughness will reduce the scope of their application,so solving the problem of poor fracture toughness becomes the focus of the research of this ceramic composite.Studies have shown that the addition of graphene can significantly improve the fracture toughness of ceramic materials,but it also brings many adverse effects on the material.In order to solve the problems of agglomeration of graphene sheets,not tightly bound to the matrix material,and fixed orientation of graphene sheets.Graphene oxide（GO）coated Si₃N₄ composite powders（Si₃N₄@GO）were prepared by particle surface modification and electrostatic self-assembly technique.Adding Si₃N₄@GO composite powders with different proportions into the matrix material to prepare Al₂O₃/（Si₃N₄@GO）（ASG）and Al₂O₃/WB₂/（Si₃N₄@GO）（AWSG）composite ceramic tool materials by Hot-Pressing Sintering.Mechanical properties and microstructure of cuttingtoolmaterialswereanalyzed,andcuttingexperimentsof Al₂O₃/WB₂/（Si₃N₄@GO）ceramic cutting tool were performed.The experimental results show when GO content is 1vol%,the mechanical properties of Al₂O₃/（Si₃N₄@GO）ceramic tool materials are the best.The flexural strength,hardness and fracture toughness of the Al₂O₃/（Si₃N₄@GO）are 626 MPa,18.6GPa and 7.6 MPa·m^1/2 respectively.When GO content is 0.5 vol%,the mechanical properties of Al₂O₃/WB₂/（Si₃N₄@GO）ceramic tool materials are the best.The flexural strength,hardness and fracture toughness of the Al₂O₃/WB₂/（Si₃N₄@GO）are 740 MPa,18.7 GPa and 8.2 MPa·m^1/2,respectively.It was found that the rGO dispersed uniformly in the Al₂O₃/WB₂ matrix and bonded tightly to the matrix,and there was no fixed orientation in the matrix.The cutting speed,cutting depth and feed rate of AWSG were studied by cutting performance test and surface roughness.The results of cutting showed that the best cutting performance of AWSG tool was obtained when the cutting speed,cutting depth and feed rate were 200 m/min,0.1 mm and 0.102 mm/r,respectively.Meanwhile,the AWSG has a maximum cutting distance of 4800 m and a relatively low surface roughness can be obtained with different cutting parameters.The abrasion mechanism of the tools was analysed in this paper as well.The wear mechanism of AWSG was abrasive wear.