| With the development of high speed,high precision,high efficiency and environmental protection,it is a significant task to improve the existing tools.The tool coating technology is a good tool to enhance cutting performance.By depositing one or more layers on the tool surface with compounds which have good hardness,wear resistance,oxidation resistance,can greatly enhance the use of tools life expectancy and processing efficiency.Tool coating is moving in the direction of diversification,compounding,nano scale and low temperature deposition,and PVD have become mainstream technology.Compared with the nano-multi-layer film,nano-composite tool coating has a wider range of applications and more practical.Based on the above background,Zr-B-O-N tool coating was prepared by high-power pulsed magnetron and pulsed DC magnetron co-sputtering technique.By analyzing the effect of oxygen content on the growth of coatings,microstructure evolution,mechanical properties,friction and wear properties,the anti-oxidation ability and the cutting performance of the coated tool,get the rule of the formation of Zr-B-O-N coating structure,the evolution law at high temperature,the change of mechanical property,tribological behavior and cutting performance law,and oxygen element on the structure and properties of Zr-B-O-N coating mechanism.The surface and cross-sectional morphology of the Zr-B-O-N coating were observed by scanning electron microscopy(SEM)and depth of field microscope.The composition of the Zr-B-O-N coating was analyzed by energy dispersive X-ray spectroscopy(EDX);the composition of the material was tested by X-ray diffraction(XRD);the hardness and elastic modulus were measured by nanometer indentation and microhardness meter;internal stress measured by the thin film stress meter;tribological properties measured by the friction and wear testing machine;wear rate measured by the surface profilometer calculated.The experimental results show that the Zr-B-O-N coating with nanocomposite structure is successfully prepared.The surface of the coating is smooth and compact.With the increase of oxygen content in the coating,the coating begins to transform from nanocomposite to nanocrystalline structure.The residual stress as a whole is small,and because of the existence of amorphous soft phase,it can play a good buffer.The hardness is higher and then decreased.When the oxygen flow ratio is 44.44%,the hardness is up to 24.12 GPa,but the wear rate is larger at this moment,on the contrary,when the oxygen flow rate reaches 66.67%,the lowest hardness and the lowest wear rate show that the hardness is not the only factor affecting the wear resistance of the coating.After heat treatment at 500 ℃,Zr-B–O –N coating with an oxygen flow ratio of 66.67%,the change of surface morphology of coating is the smallest,indicating that the more oxygen content of Zr-B-O-N coating is more excellent oxidation resistance,but at the same time cannot be ignored is the reaction of oxygen more will cause serious poisoning of the target.The coating should be prepared using a suitable oxygen flow ratio.In addition,the Zr-B-O-N coating cracked at 800 ℃.Therefore,the coating prepared in this paper is suitable for the cutting test below 800 ℃.After the process is clear,the Zr-B-O-N coating and the Zr-B-N coating were deposited on the HSS cutting tool with appropriate process parameters and make milling experiment on the Hanland XH715 D machining center.The results show that the service life of Zr-B-O-N tool coating is longer than that of Zr-B-N tool coating increased about 1.2 ~ 1.5 times,and Zr-B-N tool coating in the cutting process had a significant phenomenon of high temperature oxidation,the cutter surface produced a bond,and in the Zr-B-O-N tool coating was not found,so the addition of O elements can effectively improve the cutting performance of the coating. |
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