Research On The Technologies And Experiment Of SEM-based Instrument Indentation/nanoscratch-Atomic Force Microscopy Imaging For Mechanical Properties Characterization Of Coating

In recent years,there emerged urgent needs for functional coating materials with microto nano-scale thickness in the fields of precision maching tools,MEMS and energy saving.The existing mechanical properties characterization methods for coating materials with micro-to nano-scale thickness includes Ex-situ instrumented indentation/nanoscratch test and Scanning Electron Microscope(SEM)In-situ instrumented indentation/nanoscratch test.However,Ex-situ instrumented indentation testing method is limited by the lacking acpability of observing the testing process in real-time,and SEM In-situ instrumented indentation/nanoscratch testing method is limited by the lacking of 3D imaging in residual imprints.To overcome the two limitations above and supported by The National Natural Science Foundation of China titled "Research of nanomanipulation machine driving mechanism and nano-scale automatic manipulation"(No.61774107)and The Natural Science Foundation of the Jiangsu Higher Education Institutions of China titled "Research on the in situ SEM mechanical properties characterization and three dimension profile measurement"(No.20KJA460008),a novel SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument is developed,which acts as the new mechanical properties characterization method for coating materials with micro-to nano-scale thickness.The dissertation focuses on the SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument design,key technology in SEM-based instrumented/nanoscratch,key technology in SEM-based nanoindentation instrument,and performance tests for SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument.Finally,the mechanical properties characterization experiments for coating material TiAlSiN are conducted using the SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument.In design of SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument,a novel SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument is proposed and described.The actuator,mechanical material and electrical material are chosen piezoelectric,aluminum alloy and wire wrapped with Teflon,respectively.The size and mass of SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument are 100 mm × 100 mm × 30 mm and 346.42 g.SEM installation accessories are designed to connect the SEM-based instrumented indentation/nanoscratchatomic force microscopy(AFM)imaging instrument to main controller that placed outside the HITACHI SU5000.Finally,"human-computer" friendly software is designed based on the manipulation architecture of SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument.In technology of SEM-based instrumented indentation/nanoscratch,a novel instrumented indentation/nanoscratch transducer is deigned and the thickness of flexure hinge in transducer is optimized,T=0.15 mm.The force sensitivity and displacement sensitivity of transducer are 139.18559 μV/mN and 200.712 μV/μm,respectively.The mass and force range of the transducer are 6.83 g and 1.5 N,respectively.A novel hybrid driven nanopositioner is designed and it has nanoscratch and stick-slip positioning functions.The hybrid driven nanopositioner is used as the hybrid functions of nanoscratch,wear and coarse positioning for SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument.In order to improve the load capability of stepping working mode of stick-slip positioning function in hybrid driven nanopositioner,a flexure hinge integrating parallelogram mechanism and C-shape mechanism is designed.The maximum nanoscratch displacement,maximum movement displacement and size of hybrid driven nanopositioner are 4.9 μm,20 mm and 30 mm × 17 mm × 8 mm,respectively.The resolution of stick-slip positioning is 10 nm,and the load capability of stepping working mode of stick-slip positioning is 2 Kg.In technology of SEM-based nanoindentation instrument,a SEM-based nanoindentation instrument is developed based on the instrumented indentation/nanoscratch transducer,and its size is 95 mm × 64 mm × 38 mm.Analogue temperature compensation technique is conducted for semiconductor strain gauge position sensor in the Z nanopositioner.Firstly,semiconductor strain gauges are glued on the surface of Z nanopositioner,secondly,putting the Z nanopositioner into the programmable constant temperature and humidity test chamber,and temperature coefficient of the resistances of the semiconductor strain gauge are measured.The compensation resistances are calculated.The displacement sensitivity of Z nanopositioner is measured by the calibration experiment of Z nanopositioner.Finally,the SEM-based nanoindentation system is installed into the SEM HITACHI SU5000,and "force-depth" curve of TiAlSiN is achieved.Compared with the existing SEM-based nanoindentation system with honeywell transducer,the SEM-based nanoindentation system in this paper is capable of multi-directions observation inside SEM.In performance test for SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument,the expeiments of Ex-situ instrumented indentation and Ex-situ nanoscratch and Ex-situ wear,the experiments of SEM-based In-situ nanoscratch and Ex-situ wear,the experiment of SEM-based In-situ wear-AFM imaging are conducted for coatimg material TiAlSiN.Comparing the three experiments,the advantage of the SEM-based instrumented indentation/nanoscratch-atomic force microscopy(AFM)imaging instrument for the mechanical properties characterization of coating materials with micro-to nano-scale thickness is proved.