Research On Germanium Substrate-Assisted Focused Ion Beam Processing Of Nano-Polycrystalline Diamond Micro-Scale Tools

Nanocrystalline diamond(NPD)has better mechanical properties such as hardness,toughness and wear resistance than single crystal diamond,so it has a good application prospect in micro and nano scale high precision machining.Therefore,NPD processing into the corresponding tool,has a high application value.Among many processing methods,focused ion beam(FIB),as a micro and nano processing technology,has the advantages of high machining freedom and high machining precision,and is often used as a processing means of diamond micro-scale tools,such as surface micro-structure tools and micro-size tools.However,the FIB processing technology of micro-scale NPD tool is still in the stage of exploration.Therefore,based on FIB processing theory and material removal mechanism,imaging and machining system optimization of SEM/FIB dual-beam system,and forming process realization of micro-scale NPD tool,this paper carried out research on Germanium substrate assisted FIB processing technology for NPD micro-structure tool.The main contents are as follows:(1)The ion removal mechanism of NPD was thoroughly studied by using SRIM ion beam processing simulation software.The variation trend of ion sputtering yield under different incident ion number,ion acceleration voltage and ion incidence Angle was studied,and the damage range of ion processing area was analyzed.The results show that the maximum depth of machining damage is less than 0.05% of the hundredmicron size,and the effect is negligible.(2)Germanium substrate designed to assist FIB processing.The results show that NPD with Germanium substrate assisted processing and without Germanium substrate assisted processing can obtain clear machining morphology.In addition,it is found that the height difference at the bottom of the machined morphology decreases from 10 nm to 1 nm by comparing the NPD coated with conductive layer with and without Germanium substrate,and Germanium substrate shows excellent auxiliary machining ability.(3)The bionic microtexture of NPD tool was fabricated by Germanium substrate assisted FIB.Through cutting experiments,the effects of biomimetic micro-texture on cutting force,machining surface roughness and tool surface wear were analyzed,and the cutting performance of micro-texture tool was evaluated.It is found that the surface roughness of the biomimetic micro-texture tool is reduced by 22.8% compared with the micro-groove texture tool and the non-micro-texture tool,and the biomimetic microtexture has a significant effect on improving the tool performance.(4)Germanium substrate assisted FIB processing NPD micro tool.Firstly,the micro tool processing technology was developed,and the size of the micro tool was in line with the expectation and the blunt circle radius was 26 nm.Finally,the surface of the pure copper was cut flat,and the machining accuracy was guaranteed while the stable quality was obtained.This has important reference value for the development of the NPD micro tool in the cutting field.